2nd year Bio Guess
Ch 15
Osmoregulation different environment,excretion plants,dialysis,liver,formation & concentrators urine,thermoregulation mammals.
Ch 16
Secondary growth,locomotion mammals,plant movements,Exoskeleton,skull,v.columm,sliding.F.model,role of calcium.
Ch 24
Evidences evolution,evolution prokaryote to eukaryote,darwinism,hard weinberg theorem factors
Ch 17
Plant hormones,receptors,nerve impulse,pituitary gland,thyroid gland,adrenal Gland,ovary,comparison nervous & chemical coordination,learning behaviour.
Ch 25
Food chain food web,succession,symbiosis
Ch 18
Sexual repoduction,male & female reproductive system.
Ch 20
Exp of hershey & chase / meselson stahl,replication process,translation.
Ch 19
Moristem,Growth correlation,Embryonic induction
Ch 22
Law of segregation,multiple alleles,RH blood Group,
Ch 21
Cell cycle,prophase I meiosis I
Ch 27
Wild life,fossile fuel,eutrophication,work on electricty,wild life and its effects
Showing posts with label Biology Fsc Notes. Show all posts
Showing posts with label Biology Fsc Notes. Show all posts
Monday, 14 May 2018
Monday, 2 January 2017
Thursday, 29 December 2016
Saturday, 23 July 2016
How Fat is Lost from Body
When you lose weight, where does it go? Turns out, most of it is exhaled.
In a new study, scientists explain the fate of fat in a human body, and through precise calculations, debunk some common misconceptions. Fat doesn't simply "turn into" energy or heat, and it doesn't break into smaller parts and get excreted, the researchers say.
In reality, the body stores the excess protein or carbs in a person's diet in form of fat, specifically, as triglyceride molecue, which consist of just three kinds of atoms: carbon, hydrogen and oxygen. For people to lose weight, their triglycerides must break up into building blocks, which happens in a process known as oxidation.
When a triglyceride is oxidized (or "burned up"), the process consumes many molecules of oxygen while producing carbon dioxide (CO2) and water (H2O) as waste products.
So, for example, to burn 10 kilograms (22 lbs.) of fat, a person needs to inhale 29 kg (64 lbs.) of oxygen. And the chemical process of burning that fat will produce 28 kg (62 lbs.) of carbon dioxide and 11 kg (24 lbs.) of water, the researchers calculated.
"None of this biochemistry is new, but for unknown reasons it seems nobody has thought of performing these calculations before," study authors Ruben Meerman and Andrew Brown of the University of New South Wales in Australia, said. "The quantities make perfect sense but we were surprised by the numbers that popped out."
The researchers showed that during weight loss, 84 percent of the fat that is lost turns into carbon dioxide and leaves the body through the lungs, whereas the remaining 16 percent becomes water, according to the study published today (Dec. 16) in a special Christmas issue of medical reports
"These results show that the lungs are the primary excretory organ for weight loss. The water formed may be excreted in the urine, feces, sweat, breath, tears or other bodily fluids, and is readily replenished," the researchers said.
The calculations also show the frightening power of, for example, a small muffin over an hour of exercise: At rest, a person who weighs 154 pounds (70 kg) exhales just 8.9 mg of carbon with each breath. Even after an entire day, if this person only sits, sleeps, and does light activities, he or she exhales about 200 grams of carbon, the researchers calculated.
A 100 g muffin can cover 20 percent of what was lost.
On the other hand, replacing one hour of rest with exercise such as jogging, removes an additional 40 g of carbon from the body, the researchers said.
Even if one traces the fates of all the atoms in the body, the secret to weight loss remains the same: In order to lose weight, one needs to either eat less carbon or excercise more to remove carbon from the body.
In a new study, scientists explain the fate of fat in a human body, and through precise calculations, debunk some common misconceptions. Fat doesn't simply "turn into" energy or heat, and it doesn't break into smaller parts and get excreted, the researchers say.
In reality, the body stores the excess protein or carbs in a person's diet in form of fat, specifically, as triglyceride molecue, which consist of just three kinds of atoms: carbon, hydrogen and oxygen. For people to lose weight, their triglycerides must break up into building blocks, which happens in a process known as oxidation.
When a triglyceride is oxidized (or "burned up"), the process consumes many molecules of oxygen while producing carbon dioxide (CO2) and water (H2O) as waste products.
So, for example, to burn 10 kilograms (22 lbs.) of fat, a person needs to inhale 29 kg (64 lbs.) of oxygen. And the chemical process of burning that fat will produce 28 kg (62 lbs.) of carbon dioxide and 11 kg (24 lbs.) of water, the researchers calculated.
"None of this biochemistry is new, but for unknown reasons it seems nobody has thought of performing these calculations before," study authors Ruben Meerman and Andrew Brown of the University of New South Wales in Australia, said. "The quantities make perfect sense but we were surprised by the numbers that popped out."
The researchers showed that during weight loss, 84 percent of the fat that is lost turns into carbon dioxide and leaves the body through the lungs, whereas the remaining 16 percent becomes water, according to the study published today (Dec. 16) in a special Christmas issue of medical reports
"These results show that the lungs are the primary excretory organ for weight loss. The water formed may be excreted in the urine, feces, sweat, breath, tears or other bodily fluids, and is readily replenished," the researchers said.
The calculations also show the frightening power of, for example, a small muffin over an hour of exercise: At rest, a person who weighs 154 pounds (70 kg) exhales just 8.9 mg of carbon with each breath. Even after an entire day, if this person only sits, sleeps, and does light activities, he or she exhales about 200 grams of carbon, the researchers calculated.
A 100 g muffin can cover 20 percent of what was lost.
On the other hand, replacing one hour of rest with exercise such as jogging, removes an additional 40 g of carbon from the body, the researchers said.
Even if one traces the fates of all the atoms in the body, the secret to weight loss remains the same: In order to lose weight, one needs to either eat less carbon or excercise more to remove carbon from the body.
Friday, 22 July 2016
FSc Notes Biology Part 2 Chapter 16 Support and Movements Short Questions
Q 1. What does growth ring indicates?
Ans. Since one growth ring is formed in one year, a count of the rings at the base of trunk indicates the age of trees at the time it was cut.
Q 2. What is the function of heart wood?
Ans. In most species the heartwood accumulates a variety of chemicals such as resins, oils, gums and tannins. These provide a resistance to decay and insect attack for example in red cedar and conifers.
Q 3. What are sleep movements?
Ans. Bean plants and some members of legume family lower their leaves in the evening and raise them in the morning. These are known as sleep movements.
Q 4. What is Nyctinasty?
Ans. The nyctinastic movements are shown by the organs in response to external stimuli leading to differential growth. These are due to turgor and growth changes.
Q 5. What is cartilage?
Ans. Cartilage is much softer than bone. It is a form of connective tissue. It covers ends of the bone at the joint, and also support the flexible portion of nose and external ears. No blood vessels penetrate into cartilage.
Q 6. In how many categories joints are classified? Name them.
Ans. Joints are classified on the basis of the amount of movements allowed by them, into three categories:
- Immovable joints
- Slightly movable joints
- Freely movable joints
Q 7. What is sciatica?
Ans. It is characterized by stabbing pain radiating over the course of sciatic nerve results due to injury of proximal sciatic nerve, which might follow a fall, a herniated disc or improper administration of an injection into the buttock.
Q 8. How many steps are involved in repairing of broken bones? Name them.
Ans. The repair process of a simple fracture takes place in four phases:
- Haematoma formation
- Callus formation
- Bony callus formation
- Remodelling
Q 9. Why heart muscles are known as cardiac muscles?
Ans. Cardiac muscles are actually the muscles of heart. They constitute most of the mass of the heart walls. These muscles are also striated and involuntary. Therefore, heart muscles are known as cardiac muscles.
Q 10. What are digitigrades?
Ans. The mammals which tend to walk on their digits only are called digitigrades. They run faster than plantigrade animals e.g., rabbit, rodents etc.
Q 11. What are cross bridges?
Ans. The heads of myosin are called cross bridges which make links with actin during muscles contraction.
Q 12. What do you understand from "Rigor Mortis"?
Ans. After death, the amount of ATP in the body falls, Under these circumstances the bridges cannot be broken and so they remain firmly bound. This results in the body becoming stiff, a condition known as Rigor Mortis.
Q 13. Define sacromere.
Ans. A sacromere is the region of a myofibril between two successive Z-lines and is the smallest contractile unit of muscle fibre.
Q 14. What are chondrocytes?
Ans. The living cells of cartilage are called chondrocytes. These cells secrete flexible, elastic, non-living matrix collagen that surrounds the chondrocytes.
Q 15. What is spondylosis?
Ans. It is the disease, which causes immobility and fusion of vertebral joint.
Q 16. What is hydro-skeleton or hydro-static skeleton?
Ans. Animals may have a fluid filled gastrovascular cavity or coelom which can act as hydro-skeleton or hydro-static skeleton. Hydro-static skeleton provides support and resistance to the contraction of muscles so that motility results.
Q 17. What is the hyaline cartilage?
Ans. It is the most abundant type of cartilage in human body. It is found at the movable joints.
Q 18. What provides support in plants and animals?
Ans. The collenchymatous cells in plants give support to the baby plants and sclerenchymatous cells to the adult plants. In animals muscles, cartilage and bones provide support.
Q 19. What is turgor pressure?
Ans. The living cells of epidermis, cortex and pith take in water by osmosis. An internal hydrostatic pressure called turgor pressure develops, which keeps them rigid, resistant to bending and maintain the turgidity.
Q 20. What is Bundle cap?
Ans. In the stem of some plants, for example, sunflower, the vascular bundles are strengthened by additional sclerenchyma fibers, which form bundle cap.
Q 21. What is tonoplast?
Ans. The membrane that bounds vacuole is called tonoplast which contains a number of active transport systems that pump ions into the vacuoles.
Q 22. What are fibers or tracheids?
Ans. These are long and cylindrical and they may exist in solid bundles in xylem or as bundle caps.
Q 23. What are sclereids?
Ans. These are shorter than fibers and are found in seed coats and nutshells and provide protection.
Q 24. What are vessels or trachea?
Ans. Long tubular structures, join end to end to form long water conducting pipe in xylem.
Q 25. Define secondary growth?
Ans. Growth due to lateral meristem or cambium is called secondary growth.
Or
An increase in plant growth due to the activity of vascular cambium is called secondary growth.
The result of secondary growth is most evident in woody, perennial plants like trees, shrubs and vine.
`
Q 26. Which meristems are involved in secondary growth?
Ans. Secondary growth occurs due to cell division in:
- Vascular cambium
- Cork cambium
Ans. As trees grow older only few annual growth rings are active in conduction at one time. The active portion is called sapwood. The inactive non-conducting wood is called heartwood.
Q 28. What is callus or wood tissue?
Ans. An important function of the cambium is to form callus or wood tissue on or over the wound. Soft parenchymatous tissues are rapidly formed on or below the damaged surface of stems and roots. The callus unites the branches during budding and grafting.
Q 29. What is difference between animal and plant movements?
Ans. Animals move in response to external stimuli by motion, similarly plants also show movements. Animals change their location in response to stimulus. Plants are fixed therefore they change their growth pattern.
Q 30. What are main types of movements in plants?
Ans. There are two types of movements:
Autonomic movements
Growth movements
Q 31. What are autonomic movements. Also give their main types.
Ans. Autonomic movements are spontaneous movements due to internal causes. Autonomic movements are of three types:
- Tactic movements
- Turgor movements
- Growth movements
Ans. These are the movements of an entire cell or organism i.e. locomotion due to external stimulus. The tactic movements may be positive if it is towards the stimulus or negative if it is away from the stimulus.
Q 33. What is phototactic movement?
Ans. It is a movement in response to stimulus of light. The best example of positive tactic movements is the passive movements of chloroplast due to cyclosis. This movement helps the chloroplast to absorb maximum light for CO2 fixation.
Q 34. What is chemotactic movement.
Ans. The movements in response to stimulus of chemicals is called chemotactic movements. The movements shown by sperms of liver-worts, mosses, ferns towards archegonia in response to stimulus of nucleic acid released by the ovum are such examples.
Q 35. What is turgor movements?
Ans. Turgor movements is due to differential changes in turgor and size of cells a result of gain or loss of water. Rapid movements of leaflets in " touch me not" plant and sleep movements of the plants fall under this category of movements.
Q 36. What are growth movements?
Ans. Growth movements are due to unequal growth on two sides of plants organs like stem, root, tendrils, buds etc.
Q 37. Define epinasty.
Ans. It is shown by leaves, petals etc. The upper surface of leaf in bud condition shows more growth as compared with the lower surface. This leads to opening of buds.
Q 38. Define hyponasty.
Ans. If growth in the lower surface of the leaf in bud condition is more than that of the upper surface than the bud will remain closed.
Q 39. Define nutation.
Ans. The growing tip of young stem moves in zig zag fashion due to alternate changes in growth on opposite side of the apex. This mode of growth is called nutation.
Q 40. What are tropic movements?
Ans. It is the movement in curvature of whole organ towards or away from stimuli such as light, gravity and touch.
Q 41. Define phototropism.
Ans. It is the movement of part of the plant in response to stimulus of light and is caused due to differential growth of a plant part like stem or root.
Q 42. Define thigmotropism.
Ans. It is the movement in response to stimulus of touch, for example climbing vines. When they come in contact with some solid object, the growth on the opposite side of contact increases and the tendril coils around the support.
Q 43. Define chemotropism.
Ans. The movement in response to some chemicals is called chemotropism. The hyphae of fungi are chemotropic.
Q 44. Define hydrotropism.
Ans. The movement of plant parts in response to stimulus of water is called hydrotropism. Roots show positive hydrotropism and shoots show negative hydrotropism.
Q 45. Define geotropism or gravitropism.
Ans. It is the response to gravity. Roots display positive geotropism and shoots show negative geotropism.
Q 46. What are nastic movements?
Ans. These are the non-directional movements of parts of plant in response to external stimuli.
Q 47. Define photonasty.
Ans. The principal stimulus is the photoperiod. Flowers, open and close due to light sensitivity.
Q 48. Define thermonasty.
Ans. It is due to temperature. The flowers of tulip close at night because of rapid growth in the lower side by upward and inward bending of the petals.
Q 49. Define haptonastic movements?
Ans. It occurs in response to contact e.g., the action of the Venus fly trap.
Q 50. What is skeleton?
Ans. The skeleton is tough and rigid framework of the body of animals which provides protection, shape and support to the body organs.
Q 51. What are different types of skeleton?
Ans. There are three main types of skeleton in animals:
- Hydrostatic Skeleton
- Exoskeleton
- Endoskeleton
Q 52. Define exoskeleton.
Ans. An exoskeleton is hardened outer surface to which internal muscles can be attached.
Q 53. What is the composition of of exoskeleton?
Ans. It is composed of two layers. The epicuticle is the outermost layer and is made up of waxy lipoprotein. The bulb of exoskeleton is below the epicuticle and is called procuticle which is composed of chitin, tough, leathery, polysaccharide and several kinds of proteins.
Q 54. What is moulting or ecdysis?
Ans. When arthropods have to grow they need to shed exoskeleton periodically and replace it with one of the larger size. This process is known as Ecdysis or moulting.
Q 55. What is endoskeleton?
Ans. The skeleton that lies internally to the muscles is called endoskeleton. It provides support, shape, protection and locomotion.
Q 56. What is the composition of endoskeleton?
Ans. The endoskeleton is primarily made up of two types of tissues.
- Bones
- Cartilage
Q 57. What do you know about compact bone?
Ans. Compact bone is dense and strong and provides an attachment site for muscle.
Q 58. What are the characteristics of spongy bone?
Ans. Spongy bone is light,rich in blood vessels, and highly porous. The cavities of spongy bone contain bone marrow where blood cells are formed.
Q 59. Name the cells associated with bone?
Ans. There are three types of cells associated with bone:
- Bone forming cells (Osteoblasts)
- Mature bone cells (Osteocytes)
- Bone dissolving cells (Osteoclasts)
Q 60. What is fibro cartilage?
Ans. It has matrix containing bundles of collagen fibres. It forms an external pinnae of ear and epiglottis.
Q 61. What is axial skeleton?
Ans. The skeleton that includes the skull, the vertebrae, and the ribs and the sternum is called axial skeleton.
Q 62. Name the bones of cranium.
Ans. Parietal and temporal are paired bones, whereas frontal, occipital, sphenoid and ethmoid are unpaired bones.
Q 63. Name the bones of facial region?
Ans. The paired facial bones are maxilla, zygomatic, nasal, lacrimal, palatine and inferior concha. The unpaired facial bones are mandible and vomer.
Q 64. What is vertebral column?
Ans. Vertebral column extends from skull to the pelvis to form backbone, which protects the spinal cord. It consists of 33 vertebrae. The vertebrae are named according to their location in the body, viz, cervical, thoracic, lumbar and pelvic.
Q 65. What is sacrum?
Ans. Sacrum is formed by the fusion of anterior five vertebrae present in the pelvic region.
Q 66. What is coccyx?
Ans. Coccyx is formed by the fusion of four posterior vertebrae present in the pelvic region.
Q 67. Why lower two pairs of ribs are called "floating ribs"?
Ans. The lower two pairs of ribs are called floating ribs because they do not attach with the sternum.
Q 68. What is appendicular skeleton?
Ans. The skeleton that consists of pectoral girdle and appendages(fore limbs) and pelvic girdle and appendages(hind limbs) is called appendicular skeleton.
Q 69. What does pectoral girdle comprise?
Ans. Pectoral girdle attaches the arms to the trunk. It comprises scapula, supra-scapula and clavicle. The clavicle connects scapula with sternum.
Q 70. Name different bones of fore limb.
Ans. The fore limb consists of humerus, radius, ulna, 8 carpals, 5 metacarpals and 14 phalanges.
Q 71. What are important features of pelvic girdle?
Ans. Pelvic girdle attaches the hind limb to the vertebral column. It consists of two coxal bones. Each is formed by the fusion of three bones ilium, ischium and pubis.
Q 72. Name different parts of hind limb.
Ans. The hind limb consists of one femur, 2 tibia + fibula, 8 tarsals, 5 metatarsals and 14 phalanges.
Q 73. What different classes of joints on the basis of structure?
Ans. Joints are also classified on the basis of structure:
- Fibrous Joints
- Cartilaginous Joints
- Synovial Joints
Q 74. What are hinge joints?
Ans. The joint that allows the movements in two directions is called hinge joint. These are at elbow and knee.
Q 75. What are ball & socket joints?
Ans. These joints allow movement in several directions. Such joints have at least two pairs of muscles present perpendicular to each other. Hip joint and shoulder joint are the examples of ball and socket joints.
Q 76. What is cleft palate?
Ans. Cleft palate is a condition in which palatine processes of maxilla and palatine fail to fuse.
Q 77. What is arthritis?
Ans. Arthritis covers over 100 different types of inflammatory or degenerative diseases that damage the joints. It results in pain, stiffness, of the joints. Friction is increased.
Q 78. What is osteoporosis?
Ans. Osteoporosis is a condition of brittle and fragile bones. In this case bone mass is reduced and chemical composition of the matrix remains normal. Osteoporosis mostly occurs in aged women, which have decreased oestrogen level.
Q 79. What is osteomalcia?
Ans. Osteomalcia (soft bone) includes a number of disorders in which the bone receive inadequate minerals. In this disease calcium salts are not deposited and hence bones soften and weaken. Weight bearing bones of legs and pelvis bend and deform.
Q 80. What is rickets?
Ans. Rickets is a disease in children with bowed legs and deformed pelvis. It is caused by deficiency of calcium in diet or vitamin D deficiency.
Q 81. What is disc-slip?
Ans. Severe or sudden physical trauma to spines fro example from bending forward while lifting a heavy object may result in herniation of one or more disc. The herniated or slipped disc usually involves rupture of annulus fibrosus followed by protrusion of the spongy nucleus pulposus.
Q 82. What is closed reduction?
Ans. In closed reduction the bone end is coaxed back to their normal position by physician's hand.
Q 83. What is open reduction?
Ans. In open reduction surgery is performed and the bone ends are secured together with pins or wires.
Q 84. What are muscles?
Ans. Many multicellular animals have evolved specialized cells muscles fro movement. They contain numerous filaments of special proteins, actin and myosin.
Q 85. Name different types of muscles in vertebrates.
Ans. The vertebrates possess three kinds of muscles:
- Smooth muscles
- Skeletal muscles
- Cardiac muscles
Q 86. What are smooth muscles?
Ans. Smooth muscles are long and spindle shaped with each containing a single nucleus. It has no striations. It is not under the voluntary control. These muscles are found in the blood vessels, digestive tract and many other organs.
Q 87. What are cardiac muscles?
Ans. These are muscles of the heart. Heart muscles is composed of chains of single cell, each with its own nucleus. The chain of cells is organized into fibres that are branched and interconnected. The cardiac muscles are striated an involuntary.
Q 88. What are skeletal muscles?
Ans. The muscles that are attached with the skeleton and associated with the movement of bones are called skeletal muscles. The skeletal muscles are voluntary and striated.
Q 89. What are tendons?
Ans. Generally each end of entire skeleton muscle is attached to bone by a bundle of collagen, non-elastic fibres known as tendons.
Q 90. What is muscle fibre?
Ans. Each muscle consists of muscle bundles, which are further composed of fibres or cells. Each muscle fibre is long cylindrical cell with multiple oval nuclei arranged just beneath its sarcolemma. Their diameter is 10-100 micro meter.
Q 91. What is sarcolemma and sarcoplasm?
Ans. The cell membrane of muscle cell is called sarcolemma while its cytoplasm is called sarcoplasm.
Q 92. What are myofibrils?
Ans. When viewed in high magnification, each muscles fibre is seen to contain a large number of myofibrils, 1-2 mm in diameter, that run in parallel fashion and extend the entire length of the cell.
Q 93. What are dark and light bands in sarcoplasm?
Ans. The dark bands are called A band because they are anisotropic that is they can polarize visible light. The light bands are called I band are isotropic or non-polarizing.
Q 94. What are H-zone and M-line in A band of sarcomere?
Ans. Each A band has a lighter stripe in its midsection called H-zone (H stands for hele means bright). The H-zone is bisected by dark line called M-line.
Q 95. What is T-system?
Ans. The sarcolemma of muscle fibre cell penetrates deep into the cell to form hollow elongated tube, the transverse tubule or T-tubule. The thousands of T-tubules of each muscle cell are collectively called T-system.
Q 96. What are triads?
Ans. The T-tubule and terminal portion of the adjacent envelope of sarcoplasmic reticulum form triads at regular interval along the length of the myofibril.
Q 97. What is sliding filament model?
Ans. According to this model the thin filament slide past the thick one's so that actin and myosin filaments overlap to greater degree.
Q 98. What is a motor unit?
Ans. All the fibres innervated by a single motor neuron are a Motor Unit and contract simultaneously in response to the action potential fired by the motor neurons.
Q 99. What is other sources of energy for muscle contraction in addition to glucose?
Ans. When more energy is required due to high metabolism, it is provided by another energy storing substances called creatine phosphate.
Q 100. What is muscle fatigue?
Ans. Muscle fatigue is a state of physiological inability to contract. Muscle fatigue results from relative deficit of ATP. Excess accumulation of lactic acid and ionic imbalances also contribute to muscle fatigue.
Q 101. What is tetany?
Ans. Tetany is the disease caused by low calcium in the blood. It increases the excitability of neurons in loss of sensations. Muscle twitches and convulsion occur.
Q 102. What is cramp?
Ans. It is also known as tetanic contraction of entire muscle. It lasts for just few seconds or several hours, causing the muscles to become stretched and painful. It is most common in thigh and hip muscles.
Q 103. What are different parts of skeletal muscle?
Ans. Skeletal muscles has three parts:
- Origin
- Insertion
- Belly
Q 104. What are ligaments and tendons?
Ans. Ligaments attach bone to bone and are slightly elastic and tendons attach muscles to bones and are non-elastic.
Q 105. What are antagonistic arrangement?
Ans. At joint the muscles work against each other by contraction. This relationship is called antagonistic arrangement.
Q 106. What are brachialis & brachioradialis?
Ans. These muscles lie below the biceps brachii. The brachialis is inserted in the ulna, while brachioradialis is inserted in the radius. When these muscles contract the lift ulna and radius and bend the arm at the elbow.
Q 107. What are organs of locomotion in euglena, paramecium and amoeba?
Ans. Euglena moves with the help of flagellum. Paramecium moves with the help of cilia. Amoeba moves by means of pseudopodia.
Q 108. What is effective stroke?
Ans. Five out of nine double fibrils contract or slide simultaneously, cilia bend or shorten. It is called effective stroke.
Q 109. What is recovery stroke?
Ans. The four out of nine double fibril contract and cilia become straight. It is called recovery stroke.
Q 110. What is the type of locomotion in jellyfish and earthworm.
Ans. Jelly fish moves by jet propulsion. Earthworm shows accordion-like movement, in which setae and muscles both are involved.
Q 111. What is mode of locomotion in cockroach?
Ans. The mode of locomotion in cockroach is swift walking but it also takes to flight by its wings.
Q 112. How locomotion occurs in snail and mussels?
Ans. Snails and mussels are mollusks, which crawl or move very slowly by foot.
Q 113. What are tube feet?
Ans. Tube feet are organs of locomotion in starfish.
Q 114. What is swim bladder?
Ans. Buoyancy in the water is maintained by a specialized structure in bony fish called swim bladder.
Q 115. How wriggling occurs in amphibians?
Ans. Amphibians wriggle along the belly on the ground, with the help of segmentally arranged muscles as it swims on land with legs hardly touching the ground when moving deliberately.
Q 116. What is bipedal locomotion?
Ans. Bipedal means that animals walked on hind limbs. Bipedal locomotion freed the front appendages, which become adapted for prey capture or flight in some animals.
Q 117. What is passive flight?
Ans. When birds glide, the wings act as aerofoil. An aerofoil is any smooth surface which moves through the air at an angle to the air stream. The air flows over the wing in such a way that the bird is given lift.
Q 118. What is active flight?
Ans. When little or no support can be gained from the upward air currents, the same effect can be achieved by flapping the wings and is called active flight.
Q 119. What is plantigrade?
Ans. In this mode of locomotion the mammals used to walk on their soles with palm, wrist, and digits all lending to rest more or less on ground, such as monkeys, apes, man and bear etc.
Q 120. What is unguligrade?
Ans. The mammals walk on the tips of toes modified into hoof such as deer, goat. It is the swiftest type of locomotion.
Q 121. What is the cause of muscle cramp?
Ans. It is caused by:
- Low blood sugar
- Electrolytic dapletion
- Dehydration
- Irritability of spinal cord and neurons.
FSc Notes Biology Part 2 Chapter 24 Evolution Short Questions
Q 1. What are the sources of hydrogen for reducing CO2 in first photosynthetic organism?
Ans. The first photosynthetic organism probably used hydrogen sulphide as a source of hydrogen for reducing carbon dioxide to sugars.
Q 2. Which idea is known as endosymbiont hypothesis?
Ans. The eukaryotic cell might have evolved when a large anaerobic amoeboid prokaryotic ingested small aerobic bacteria and stabilized them instead of digesting them. This is known as endosymbiont hypothesis.
Q 3. What was the second idea of Lamarck called?
Ans. The second idea of Lamarck adopted, was called the inheritance of acquired characteristics. In this concept of heredity, the modifications an organism acquires during its lifetime can be passed along to its offspring e.g., the long neck of the giraffe.
Q 4. What is the important turning point for evolutionary theory?
Ans. The origin of species convinced most biologists that species are products of evolution. An important turning point for evolutionary theory was the birth of population genetics, which emphasizes the extensive genetic variation within populations and recognizes the importance of quantitative characters.
Q 5. How natural selection occurs?
Ans. Natural selection occurs through an interaction between the environment and the variability inherent in any population.
Q 6. What was the statement or theorem of Hardy-Weinberg?
Ans. It states that the frequencies of alleles and genotypes in a population's gene pool remain constant over the generation unless acted upon by agents other than sexual recombination.
Q 7. Which mating is called non-random mating?
Ans. Individuals with certain genotypes sometimes mate with one another more commonly than would be expected on a random basis. This is called non-random mating.
Q 8. On what evidence Darwin's theory of evolution was mainly based.
Ans. Darwin's theory of evolution was mainly was mainly based on evidence from the geographical distribution of species and from the fossil record.
Q 9. Who was Darwin's predecessor who developed a comprehensive model that attempted to explain how life evolves?
Ans. Jean Baptiste Lamarck (1744-1829).
Q 10. What is spirochete?
Ans. A helical bacterium which is flexible and has periplasmic flagella is called spirochete.
Q 11. Define bio-geography.
Ans. The study of geographical distribution of life on earth. Bio-geographers attempt to explain the factors that influence where species of plants and animals live on earth.
Q 12. What are fossils?
Ans. Any remain, impressions or traces of organisms of a formal geological age.
Q 13. Define embryology.
Ans. Study of animal development from fertilized egg to formation of all major organs.
Q 14. What is molecular biology?
Ans. The study of biochemical structures and function of organisms at molecular level.
Q 15. What does evolution refer?
Ans. Evolution refers to the processes that have transformed life on earth from its earliest forms to the vast diversity that is observed today.
Q 16. What is the concept of special creation?
Ans. According to the theory of special creation all living things came into existence in their present forms especially and specifically created by nature. Among the scientists who believed in divine creation was Carolus Linnaeus.
Q 17. What is the concept of Evolution.
Ans. The idea that organisms might evolve through time, with one type of organism giving rise to another type of organism is called evolution.
Q 18. What Darwin said about Finches of Galapagos?
Ans. Among the birds Darwin collected 13 types of finches that, although quite similar, seemed to be different species. Some were unique to individual islands, while other species were distributed on two or more islands that were close together.
Q 19. What did Lamarck said about the use and disuse of organs?
Ans. Lamarck argued that those parts of the body used extensively to cope with the environment become larger and stronger, while those that are not used deteriorate.
Q 20. What was Darwin's idea of Origin of Species?
Ans. A new species would arise from an ancestral form by the gradual accumulation for adaptations to different environment, separated from original habitat by geographical barriers. Over many generations, the two population could become dissimilar enough to be designated separate species.
Q 21. What was the contribution of Wallace in the development of theory of natural selection?
Ans. Alfred Wallace developed a theory of natural selection essentially identical to Darwin's. Wallace's paper, along with extracts from Darwin's unpublished 1844 essay, were presented to the Linnaean society of London on July 1, 1858.
Q 22. Define the theory of natural selection.
Ans. Nature will select the organism whose inherited characteristics fit them best to their environment and eliminate others.
Q 23. What is Neodarwinism?
Ans. According to neodarwinism the new species evolve due to extensive genetic variation within populations and natural selection.
Q 24. What does indicate that prokaryotes are ancestors of all life?
Ans. Evidence from biochemistry, molecular biology, and cell biology places prokaryotes as the ancestors of all life, and predicts that bacteria should precede all eukaryotic life in the fossil record.
Q 25. What are homologous structures?
Ans. Similarity in characteristics resulting from common ancestry is known as homology, and such anatomical signs of evolution are called homologous structures. For example: the forelegs(cat etc.), wings(bat), flippers(whale), and arms(man).
Q 26. What are vestigial organs?
Ans. Vestigial organs are historical remnants of structures that had important functions in ancestors but are no longer essential. For instance: vermiform appendix in carnivores and man.
Q 27. Name some vestigial structures in man.
Ans. Ear muscles, nictitating membrane, vermiform appendix and coccyx in man are vestigial structures.
Q 28. Differentiate between homologous and analogous organs.
Ans. Homologous organs are functionally different but structurally alike e.g., forelimbs of man, bat, horse, whale, etc., are example of divergent evolution. Analogous organs are functionally alike but structurally different e.g., wings of bat, birds and insects are examples of convergent evolution.
Q 29. Differentiate between natural selection and artificial selection.
Ans. Natural selection occurs through an interaction between the environment and the variability inherent in any population, while the selective breeding of domesticated plants and animals by man is called artificial selection.
Q 30. What is population?
Ans. Population is a group of inter-breeding individuals belonging to a particular species and sharing a common geographic area or a population is a localized group of individuals belongings to the same species.
Q 31. Define species.
Ans. A species is a group of individuals that have the potential to interbreed in nature.
Q 32. What is gene pool?
Ans. The total aggregate of genes in a population at one time is called the population's gene pool. It consists of all alleles at all gene loci in all individuals of the population.
Q 33. Define the Hardy-Weinberg theorem.
Ans. It states that the frequencies of alleles and genotypes in a population's gene pool remain constant over the generation unless acted upon by agents other than sexual recombination.
Q 34. What is Hardy-Weinberg equation used for?
Ans. A general formula, called the Hardy-Weinberg equation is used for calculating the frequencies of alleles and genotypes in populations at equilibrium.
Q 35. What factors affect the gene frequency?
Ans. Factors that affect that gene frequency:
- Mutation
- Migration
- Genetic drift
- Non-random mating
- Selection
Q 36. Differentiate between endangered and threatened species.
Ans. A species which is in imminent danger of extinction throughout its range is called endangered species. A threatened species is likely to become endangered in the near future.
Q 37. What are hydrothermal vents?
Ans. Hydrothermal vents are hot springs deep in the oceans, in underwater where life may have begun.
Q 38. Name any five species, declared extinct in Pakistan.
Ans. Cheetah, Tiger, Asian lion, Indian rhino, Crocodile, Cheer pheasant.
FSc Notes Biology Part 2 Chapter 26 Some Major Ecosystems Short Questions
Q 1. Can you differentiate between altitude and latitude?
Ans. The angular distance on a meridian(circle passing through poles) north or south of the equator, expressed in degrees and minutes is called latitude. While height in relation to equator is called altitude.
Q 2. How many regions open water area is divided into?
Ans. The open water area is divided into two regions:
- The upper Limnetic zone
- The lower Profundal zone.
Q 3. What is hydrospheric or aquatic ecosystem?
Ans. Hydrospheric ecosystem is a system in water where living and non-living components exchange material and transfer of energy also takes place within water.
Q 4. What are plankton?
Ans. Living among the anchored plants are microscopic organism called plankton. These can be divided into two groups:
- Phytoplankton: Greek meaning "drifting plants". They include photosynthetic protista, bacteria and algae.
- Zooplankton: Greek meaning "drifting animals". Such as protozoa and tiny crustaceans.
Q 5. What types of organisms are present in profundal zone of lake?
Ans. Decomposers and detritus feeders such as snails and certain insect larvae, bacteria, fungi and fishes are present in it.
Q 6. Name the sub-divisions of forest ecosystem.
Ans. Forest ecosystem is further sub-divided into:
- Tropical Rain Forests
- Temperate Deciduous Forest
- Coniferous Alpine and Boreal Forest.
Q 7. What type of animals are present in temperate decicuous forest.
Ans. Some very common animals are Macaca mulatta (Rhesus Monkey), Solenorotos tibitanus (black bear), Felis bengalensis (leopard cat), deer, and wolves with various types of micro-organisms to convert the litter into organic matter such as bacteria, fungi and earthworm.
Q 8. What is the location of coniferous alpine and boreal forests?
Ans. In Pakistan these forest are in upper Kaghan, Dir and Chilas, Malam Jaba in Swat valley. In world they stretch across Eurasia (Europe + Asia) and North America, Canada just south of the Tundra.
Q 9. Name some grasslands of Pakistan.
Ans. Grassland ecosystems are found in Gilgit, Kashmir, Waziristan, lower Chitral and North Kallat.
Q 10. What is layering in ecosystem?
Ans. Layering is the characteristics of grassland. Tall grasses from the first layer, mid high grasses from the second layer and third layer is formed by short grasses and forbs and warfare species with mosses and lichens.
Q 11. Define productivity of an ecosystem.
Ans. Productivity can be defined as the rate of production of new biomass during the period under consideration. Productivity is generally expressed in terms of grams or kilo-calories per sq. meter or hector per sq. meter per year.
Q 12.Name three zones in lake ecosystem.
Ans. Three zones in lake ecosystem are as under:
- Littoral zone: Shallow water area.
- Limnetic zone: Open water area with light penetration.
- Profundal zone: Deep, dark water area without light penetration.
Q 13. How many biomes are present in the world, name only five of them.
Ans. 10 biomes are present in the world e.g., Tropical rain forest, Tropical deciduous forest, Tropical scrub forest, Savanna, Temperate grassland, Temperate deciduous forest, Desert, Taiga, Tundra and Chaparral.
Q 14. Give the names of some major ecosystem on land in Pakistan.
Ans. Major ecosystems in Pakistan:
- Temperate Deciduous forest
- Coniferous Alpine and Boreal Forests
- Grass land Ecosystem
- Desert Ecosystem
- Tundra Ecosystem
Q 15. What are the four major requirements for life?
Ans. Major requirement for life are:
- Light
- Nutrient
- Water
- Temperature
- Air
Q 16. Differentiate between weather and climate.
Ans. Weather refers to short term fluctuations in temperature, humidity, cloud cover, wind and precipitation over periods of hours or days. Climate in contrast refers to overall patterns of weather that prevail from year to year even century to century in a particular region,
Q 17. What are the characteristics of littoral zone?
Ans. In this zone the water is shallow, and plants find abundant light, anchorage and adequate nutrients from the bottom sediments.
Q 18. What is the location temperate deciduous forests in Pakistan and rest of the world.
Ans. In Pakistan temperate moist conditions are present in Neelam valley and Shogran. These forests originally covered India, Southeast Asia, Eastern North America, Europe, China, Australia, Japan, North and South America.
Q 19. What is the range of rainfall and temperature in temperate deciduous forest?
Ans. The average rainfall is between 750-1500 mm. Moderate temperature ranges from 4 degree Celsius to 30 degree Celsius.
Q 20. Name the plants of temperate deciduous forest?
Ans. Some dominant trees are: Taxus baccata, Pinus wallichiana, Berberis lyceum usually with height 8 to 30 meters.
Q 21. What is taiga?
Ans. Northern coniferous forests are also called taiga.
Q 22. Differentiate between alpine and boreal forests.
Ans. Coniferous forests located at high altitude are called alpine while coniferous forests located at high latitude are called boreal forests.
Q 23. What do you know about the animal life of coniferous alpine and boreal forests?
Ans. Large mammals, bison, wolf, black bear, deer, Marco polo sheep and smaller animals such as small Kashmir flying squirrel, snowshoe hare, wolverine, crossbills are present.
Q 24. Name the plants of coniferous alpine and boreal forests?
Ans. Plants like Pinus wallichiana, Pinus roxburgii, Abies pindrow, Picea smithiana, Cederous deodara are present.
Q 25. What are prairies?
Ans. Grasslands present in temperate climates are called Prairies,such as Prairies of North America, pampas of Argentina. These grasslands do not have woody plants so they are known as prairies.
Q 26. What is Savanna?
Ans. The grasslands in tropic climates have woody trees and are called Savanna.
Q 27. What is the annual rain fall in grasslands?
Ans. Annual rainfall is about 250 to 750 mm. The grasslands usually face severe rains, which in tropical and subtropical grasslands, reaches about 1500 mm.
Q 28. Name some predators of grassland.
Ans. The predators are reptiles, amphibians and mammals, such as Lizards, toads and turtles prey on insects. Foxes and wolves among mammals are very common.
Q 29. What is the productivity of grassland ecosystem?
Ans. In temperate grasslands the rate of primary production is about 700-1500 g/cm2 annually. In sub humid tropical grasslands it is more than 4000 g/cm2.
Q 30. What is the location of deserts in Pakistan?
Ans. In Pakistan the desert ecosystems are found in western Punjab where it is known as Thal. In southern Punjab, areas like Fort Abbas. Bahawal Nagar, Yazman Bahawal Pur, Khan pur and Rahim yar khan also have deserts. In Sindh this desert ecosystem is called Thar.
Q 31. What is desertification?
Ans. While human activities are reducing the extent of many biomes, they are causing the spread of deserts, a process called desertification.
Q 32. What is tundra?
Ans. It is used to describe types of vegetation in treeless high latitudes between taiga and polar ice caps, and at high altitude across the mountain above timberline such as mountain of Karokaram and Koh Hindukush in Pakistan.
Q 33. What types of plant life is found in tundra?
Ans. The ground is carpeted with small perennial flowers and dwarf willows no more than a few centimeters tall often with large lichen called rein deer moss.
Q 34. What type of animal life if present in tundra?
Ans. The standing pools provide superb mosquito habitat. The mosquitoes and other insects provide food fore numerous birds. The tundra vegetation supports lemmings, which are eaten by wolves, snowy owls, arctic foxes and even grizzly bears.
FSc Notes Biology Part 2 Chapter 17 Coordination and Control Short Questions
Q 1. Define coordination?
Ans. All the aspects such as organization, regulation, integration and control in the constitution and work of the complex multicellular animals come under the fold of the term coordination.
Q 2. Why Chlorosis arises?
Ans. Chlorosis usually arises from short supplies of mineral nutrients in the soil.
Q 3. In higher animals how coordination is brought about?
Ans. It is brought about in higher animals by nervous coordination and chemical coordination.
Q 4. What are photoreceptors?
Ans. Photoreceptors are electromagnetic receptors. These respond to stimuli of light for example in eyes, rods and cones.
Q 5. What is Neuroglia?
Ans. The chief structural and functional unit of the nervous system is neurons, but there are other cells, in higher animals, and in humans called Neuroglia, which make up as much as half of the nervous system.
Q 6. What are cranial nerves?
Ans. In human, there are 12 pairs of nerves, which arises from the brain, or lead to the brain these are called cerebral or cranial nerves.
Q 7. What is the effect of nicotine on coordination?
Ans. Nicotine affects postsynaptic membrane in CNS and PNS. It minimizes the action of acetylcholine on nicotine receptors, so it is stimulant of nerve impulse. It increases the heart beat rate, blood pressure and digestive tract mobility, Nicotine may induce vomiting and diarrhea and even may cause water retention relation by kidneys.
Q 8. What ethologists think about animal’s response?
Ans. The early ethologists (Uexkull 1935, Lorenz 1935) thought that animals sometimes respond instinctively to specific though often complex stimuli such stimuli came to be called “sign stimuli”.
Q 9. Define learning behavior?
Ans. Thrope defined learning as that process which manifests itself by adaptive changes in individual behavior as a result of experience.
Q 10. Who has demonstrated and studied operant conditioning or conditioned reflex type II?
Ans. This type of learning has been demonstrated and studied by Thorndike and B.F Skinner a Harvard psychologist.
Q 11. How neuron fibres and cell bodies can be exited?
Ans. The neuron fibres and cell bodies can be excited by small electric shocks, mechanical, chemical, light and temperature stimuli.
Q 12. How plants respond to the stimuli?
Ans. Plants respond by.
- Regulating their growth and development in appropriate ways.
- Controlling their body functions through plant hormones or growth hormones.
Q 13. Which type of plants are said to etiolated?
Ans. If plants are grown without light, they become extremely long and they fail to form chlorophyll. They are said to be etiolated.
Q 14. What is Chlorosis?
Ans. Many plants take on a yellowish hue when they fails to form chlorophyll in sufficient amounts. This condition is known as Chlorosis.
Q 15. What are Calluses?
Ans. If plants are wounded, they often develop masses of amorphous (formless or shapeless) material with very poor differentiation known as calluses.
Q 16. What are galls?
Ans. Galls are growths on a plant that are induced by parasites and usually, highly organized growth galls are tumors induced by the bacteria. They are usually less differentiated the other types of galls.
Q 17. Define biorhythms or biological rhythms?
Ans. In living things he behavioral activities occur at regulars intervals which are called biorhythms or biological rhythms.
Q 18. What are diurnal rhythms?
Ans. Biorhythms may occur showing periodicity of about 24-hours. These are called circadian which means about one day, so they are also called diurnal rhythms.
Q 19. What is Circaannual?
Ans. If the biorhythms are less than or about 365 days, these rhythms in activity are called Circaannual.
Q 20. What are plant hormones?
Ans. The special substances produced by the plants which influence the growth and plants responses to various stimuli are called plant hormones.
Q 21. Name different plant hormones?
Ans. Auxins, giberrellins, cytokinins, abscisic acid and ethane.
Q 22. Give two functions of giberrellins?
Ans. Functions of giberrellins
- Promote cell enlargement in presence of Auxins.
- Promote leaf growth and fruit growth.
Q 23. What is use of GA3?
Ans. GA3 is used in the brewing industry to stimulate amylase production in barely and this promotes malting.
Q 24. Give two functions of Cytokinins?
Ans. Functions of cytokinins
- Promote stern growth by cell division in apical meristerm and cambium.
- Promote bud initiation.
Q 25. What is commercial application?
Ans. Cytokinins delay the aging of fresh leaf crops, such as cabbage and lettuce (delay of senescence) as well as keeping flowers fresh. They can also be used to break dormancy of some seeds.
Q 26. Give two functions of Abscisic acid?
Ans. Functions of Abscisic acid
- Inhibits stern growth notably during physiological stress, e.g., drought, water-logging.
- Promotes bud dormancy.
Q 27. What is commercial application of abscisic acid?
Ans. Abscisic acid can be sprayed on tree crops to regulate fruit drops the end of the season. This removes the need for picking over a large time-span.
Q 28. What is commercial application of ethane?
Ans. Ethane induces flowering in pineapple. It stimulates ripening of tomatoes and citrus fruit. It stimulates flow of latex in rubber plants.
Q 29. What is nervous coordination?
Ans. This type of coordination involves specialized cells or neurons linked together directly or via the central nervous system, to form network that connect the cell or organs which receive stimuli (receptors) and those which carry out actions or responses (effectors).
Q 30. What are elements of nervous system?
Ans. The elements of nervous system which help in co-ordination are.
- Receptors
- Neurons
- Effectors.
Q 31. What are Receptors?
Ans. Receptors detect changes in the external and internal environment of the animal. The receptor may be a cell, or neuron ending or a receptor organ.
Q 32. What are chemoreceptors?
Ans. The receptors which are stimulated by the chemicals are called chemoreceptors. These are for smell, taste and for blood CO2 oxygen, blood glucose, amino acids and fatty acids.
Q 33. What are Mechanoreceptors?
Ans. The receptors which detect stimuli of touch, pressure and hearing and equilibrium are called mechanoreceptors.
Q 34. What are thermo-receptors?
Ans. The receptors which respond to cold and warmth are called thermo-receptors.
Q 35. What are nociceptors?
Ans. These are undifferentiated nerve endings which produce the sensation of pain.
Q 36. What is modality of sensation?
Ans. Each type of principle type of sensation that we can experience e.g., pain, touch, sight, sound and so forth is called a modality of sensation.
Q 37. What are Meissner's corpuscles?
Ans. These are encapsulated nerve endings which is lie in papillae which extend into the ridges of the fingertips. The corpuscle consists of spiral and much twisted endings, each of which ends in a knob. These are touch receptors.
Q 38. What are Pacinian corpuscles?
Ans. Pacinian corpuscles are situated quite deep in the body. These are encapsulated neuron endings and receive deep pressure stimulus. Those located in the limbs probably form a basis for vibration sense.
Q 39. What is Dendron or are dendrites?
Ans. The cytoplasmic process which carries impulse towards cell body is called Dendron, if it is a single fibre but if smaller fibres they are called dendrites.
Q 40. What are Axons?
Ans. The processes conducting impulses away from cell body are termed axons. These may be more than a meter long in some neurons.
Q 41. What are Nissl's granules?
Ans. Nissl's granules are groups of ribosomes associated with rough endoplasmic reticulum and protein synthesis and Golgi apparatus and are present in the cell body.
Q 42. What is Cell body or soma?
Ans. The cell body or soma is the main nutritional part of the nerve cell and is conserved with the biosynthesis of materials necessary for the growth and maintenance of the neuron.
Q 43. Name different types of neurons?
Ans. There are three functional types of neurons in mammals i.e., the sensory, associative (intermediate / relay) and motor neurons.
Q 44. What are Sensory Neurons?
Ans. These are the neurons which carry nerve impulses from receptors to brain or spinal cord. They have a single, elongated Dendron and shorter axon.
Q 45. What are Motor Neurons?
Ans. These are the neurons which carry nerve impulses from brain and spinal cord to the effectors in all parts of the body. They have a long axon and number of small dendrites.
Q 46. What are Associative Neurons?
Ans. These are the neurons which occur exclusively in the spinal cord and brain. They serve as intermediate links between numerous sensory and motor neurons.
Q 47. What are Effectors?
Ans. These are the structures which respond when they are stimulated by impulse coming via motor neuron. The principal effectors are glands, which respond by secreting; and muscles which respond by contracting.
Q 48. What is reflex arc?
Ans. Reflex arc is the path way of passage of impulse during a reflex action. Reflex action is a type of involuntary action. The direction of stimulus is form receptors to sensory neurons to associative neuron and then through motor neuron to the effectors.
Q 49. Define nerve impulse?
Ans. Nerve impulse is a wave of electrochemical changes, which travel along the length of the neuron involving chemical reactions and movement of ions across the cell-membrane.
Q 50. Define electrical potential and membrane potential?
Ans. Electrical potential is a measure of the capacity to do electrical work. The electrical potential that exists, across a cell membrane is known as membrane potential.
Q 51. What is resting membrane potential?
Ans. A typical neuron at rest is more positive electrically outside than inside the cell membrane. This net difference in characteristics between the inner and outer surface of a non-conducing neuron is called the resting membrane potential.
Q 52. What is active membrane potential?
Ans. After initiation of nerve impulse the resting membrane potential disappears for a brief instant and is replaced by a new potential called active membrane potential which is in the form of impulse.
Q 53. What is salutatory impulse?
Ans. It may be added that in myelinated neurons the impulse jumps from node to node (node or Ranvier). This is called salutatory impulse.
Q 54. What is synapse?
Ans. There is no cytoplasmic connection between the two neurons and microscopic gaps are left between them .Each of these contact points is known as synapse.
Q 55. How does nerve impulse pass from one neuron to other through the synapse?
Ans. A nerve impulse is passed from one neuron to the other through the synapse with the help of chemical messenger, called neurotransmitters.
Q 56. What are neurotransmitters? Give their various types?
Ans. Neurotransmitters are chemicals which are released at the axon ending of the neurons, at synapse. Acetylcholine, adrenaline, nor epinephrine, serotonin and dopamine are some neurotransmitters.
Q 57. What is Acetylcholine?
Ans. Acetylcholine is the main neurotransmitter for synapses that lie outside the central nervous system.
Q 58. What are different designs of nervous systems in the animal kingdom?
Ans. Designs of nervous system in animal kingdom
- Diffused nervous system It is found in Cnidarians (Hydra, jelly fish and their relatives).
- Centralized nervous system It is found to varying degrees in more complex organisms, from Platyhelminthes to choradates including humans.
Q 59. What are the main parts of nervous system of man?
Ans. Main parts of nervous system of man
- Central Nervous System.
- Peripheral Nervous System.
Q 60. Name the two parts of central nervous system?
Ans. Parts of Central Nervous System
- Brain
- Spinal Cord.
Q 61. What is Cranium?
Ans. Cranium is part of skull which protects the brain and neural arches of vertebrae.
Q 62. What are Meninges?
Ans. Beneath the cranium, the brain and spinal cord are protected by triple layer of Meninges.
Q 63. What is Cerebrospinal fluid (CSF)?
Ans. Between the layers of Meninges, the cerebrospinal fluid (CSF), is present which bathes the neurons of brain and spinal cord and cushions against the bumps and jolts.
Q 64. Name different parts of brain?
Ans. The brain can be divided into forebrain, mid brain and hind brain.
Q 65. Name various parts of forebrain?
Ans. Forebrain is divided into three functional parts.
- The thalamus
- The limbic system
- The cerebrum.
Q 66. What is the function of Thalamus?
Ans. Thalamus carries sensory information to the limbic system and cerebrum. The information includes sensory input from auditory and visual pathways from the skin and from within the body.
Q 67. How does limbic system work?
Ans. Limbic system work together to produce our most basic and primitive emotions, drives, the behaviors, including fear, rage, tranquility (calmness, peace of mind), hunger, thirst, pleasure and sexual responses.
Q 68. What are various parts of limbic system?
Ans. The limbic system consists of hypothalamus, the amygdala, and hippocampus, as well as nearby regions of cerebrum.
Q 69. What is role of Hypothalamus?
Ans. The hypothalamus acts as a major co-ordinating centre controlling body temperature, hunger, the menstrual cycle, water balance and the sleep-wake cycle.
Q 70. What is role of Amygdala?
Ans. In the amygdala, the cluster of neurons produces sensation of pleasure, punishment or sexual arousal when stimulated. It is also involved in the feelings of fear and rage.
Q 71. What is the function of Hippocampus?
Ans. Hippocampus plays an important role in the formation of long term memory, and thus is required for learning.
Q 72. What are cerebral hemispheres?
Ans. Cerebrum is the largest part of the brain and is divided into two halves, called cerebral hemispheres. The left cerebral hemisphere controls the right side of the body, and right cerebral hemisphere controls the left side of the body.
Q 73. What is corpus callosum?
Ans. The two cerebral hemispheres communicated with each other by means of a large band of axons, called corpus callosum.
Q 74. What is cerebral cortex?
Ans. It is the outer region of the cerebrum. It forms folds called convolutions, which greatly increase its surface area.
Q 75. What is reticular formation?
Ans. Midbrain contains reticular formation, which is a relay centre connecting hindbrain with the forebrain. It is very important in screening the input information, before they reach higher brain centers.
Q 76. Name different parts of Hindbrain?
Ans. Hindbrain includes the medulla, pons and cerebellum.
Q 77. What is the function of Medulla?
Ans. Medulla controls several automatic functions, such as breathing, heart rate, blood pressure and swallowing.
Q 78. What is the role of Pons?
Ans. Certain neurons in pons, located above the medulla, appear to influence transitions between sleep and wakefulness, and the rate and pattern of breathing.
Q 79. What is the role of cerebellum?
Ans. The cerebellum is important in co-ordinating movements of the body. The cerebellum guides, smooth and accurate motions and body position. The cerebellum is also involved in the learning and memory storage of behaviors.
Q 80. What is spinal cord?
Ans. Medulla oblongata narrows down into an oval shaped hollow cylinder, the spinal cord, running through the vertebral column. It is made up of a very large number of neurons, the cell-fibres and bodies of which are arranged in a definite pattern.
Q 81. What is grey matter?
Ans. In cross section, the spinal cord shows an inner butterfly shaped grey matter, containing a central canal. It consists of cell bodies and non-myelinated nerve fibres or tracts.
Q 82. What is white matter?
Ans. The outer portion of spinal cord is composed of white matter. It s made up of myelinated nerve fibres or tracts.
Q 83. What is the composition of peripheral nervous system (PNS)?
Ans. It comprises sensory neurons and motor neurons, which may form ganglia and the nerves.
Q 84. Ganglia are the concentrations of cell bodies of neurons?
Ans. Ganglia are the concentrations of cell bodies of neurons.
Q 85. What are Nerves?
Ans. The nerves are the bundles of axons or dendrites, bounded by connective tissue. They may be sensory, mixed or motor nerves depending upon the direction of impulse they conduct.
Q 86. What is chemical coordination?
Ans. The coordination brought about by the chemicals is called Chemical coordination.
Q 87. What are spinal nerves?
Ans. From the spinal cord 31 pairs of spinal nerves arise or lead to spinal cord. All these nerves are mixed i.e., having fibres sensory and motor neurons.
Q 88. What is Somatic nervous system?
Ans. Motor neurons form somatic nervous system, which controls voluntary movements, which are under the conscious control of the boyd, involving skeletal muscles.
Q 89. Name different parts of autonomic nervous system?
Ans. The autonomic nervous system is further divided into sympathetic nervous system and parasympathetic nervous system.
Q 90. What is the role of Sympathetic nervous system?
Ans. This system is important during emergency situations and is associated with "fight or flight". This system accelerates the heart beat and dilates and inhabits the digestive tract.
Q 91. What is Parasympathetic nervous system?
Ans. A few cranial nerves including the vagus nerve together with fibres from the bottom portion of spinal cord, form the parasympathetic nervous system. It promotes all the internal responses i.e., contracts of the pupils, promotes digestion of food, retards heart beat.
Q 92. Name a few nervous disorders.
Ans. Parkinson's disease, Addison's disease, Epilepsy and Alzheimer's disease.
Q 93. What is Parkinson's disease (paralysis agitans)?
Ans. It is a nervous disorder, characterized by involuntary tremors, diminishing motor power and rigidity. The mental faculties are not affected. The disease is believed to be caused by cell death in a brain area that produces dopamine.
Q 94. What is Epilepsy?
Ans. It is one of the convulsive disorders of nerves which are characterized by abrupt transient symptoms of motor, sensory psychic or autonomic nature, frequently associated with changes in consciousness. The onset of epilepsy is usually before age 30.
Q 95. What is Alzheimer's disease?
Ans. Alzheimer's disease was first described by Alois Alzheimer in 1907. It characterized by the decline in brain function. It tends to run in families. There is also evidence that high levels of aluminum may contribute to the onset of disease.
Q 96. What are hormones?
Ans. The endocrine or ductless glands are with a few exceptions, discrete groups of cells, which make specific chemicals compounds called hormones Endocrine system consists of some 20 endocrine glands / tissues lying in different parts of the body.
Q 97. Give two characteristics of Hormones?
Ans. Characteristics of Hormones
- They are poured directly into the blood stream.
- They are transported to respective target tissues by the blood.
Q 98. What is Hypothalamus?
Ans. It is parts of the fore brain. It is here that many of the sensory stimuli of nervous system are converted into hormonal responses.
Q 99. What is Pituitary Gland?
Ans. In man the pituitary gland or hypophysis cerebri is an ovoid structure about 0.5 gm in the adult and is connected to brain through a short stalk (the infundibulum). It has three lobes viz, anterior, median and posterior.
Q 100. Why pituitary gland is called Master gland?
Ans. The anterior lobe of pituitary is often referred toas the master gland, because in addition to producing primary hormones it produces the trophic hormones which control the secretion of hormones in many of the other endocrine glands.
Q 101. Name different hormones released by anterior lobe of pituitary gland?
Ans. Anterior lobe of pituitary secretes the following hormones:
- Somtotrophin.
- Thyroid stimulating hormone.
- Adenocorticotrophic hormone.
- Gonadotrophic hormones. i) FSH and LH/ICSH. ii) Prolactin.
Q 102. Name the hormones released by median lobe of pituitary gland?
Ans. Median lobe secretes the following hormones:
- Melanophore stimulating hormone.
Q 103. Name the hormones released by posterior lobe of pituitary gland?
Ans. Hormones released by Posterior lobe of pituitary gland
- Anti-diuretic hormone (ADH: also called vasorpressin).
- Oxytocin.
Q 104. Give one function of thyroxine and tri-iodothyronine?
Ans. Thyroxine and tri-iodothyronine act on the basal metabolic rate by stimulating the breakdown of glucose and release of heat and generation of ATP.
Q 105. What is the effect of over-secretion of thyroxine?
Ans. Excess thyroxine produced a condition called Graves' disease, with exophthalmic goiter and increase in the basla metabolic rate. This can lead to cardiac failure if prolonged.
Q 106. What is cretinism?
Ans. In infants, the deficiency of thyroxine causes a dwarfed condition called cretinism. The individual are small, have coarse scanty hair, thick yellowish scaly skin and mentally retarded.
Q 107. What is myxedema?
Ans. Deficiency of thyroxine in adults, perhaps due to iodine shortage in diet, produces a swelling o the neck (goiter) and may lead to laying down of excess fat and weight is increased. The condition is known as myxedema.
Q 108. What is calcitonin?
Ans. It is hormone released by thyroid gland in response to high Ca2+ concentration in the blood. Excess or deficiency leads to a disturbance of calcium metabolism with its associated effects on nerve, skeleton, muscle, blood etc.
Q 109. What is action of glucagon?
Ans. Glucagon causes an increase in blood glucose levels. It does this mainly by promoting breakdown of glycogen to glucose in the liver and muscles. It also increases the rate of breakdown of fats.
Q 110. Name the hormones released by adrenal gland?
Ans. The medulla produces the hormones adrenaline and nor-adrenaline. The adrenal cortex secretes aldosterone and androgenic hormones.
Q 111. What is the function of aldosterone?
Ans. Aldosterone is a mineralcortioid which conserves the level of Na+ ions in the body by preventing their loss from the kidney tubules.
Q 112. What is the function of Cortisol?
Ans. Cortisol brings about an increase in blood glucose level mainly by its production from protein and by antagonizing the action of insulin.
Q 113. What is the function of Corticosterone?
Ans. Corticosterone is bot a glucorticoid and mineralocorticioid, it increases blood glucose levels and regulates mineral ion balance.
Q 114. What is Cushing's disease?
Ans. In chushing's disease too much cortical hormone is produced. Symptoms are an excessive protein breakdown resulting muscular and bone weakness. The high blood sugar disturbs the metabolism as in diabetes.
Q 115. What are Androgens?
Ans. Androgens cause development of the secondary male characters. Very small amounts of androgens are secreted in both male and female adrenal glands.
Q 116. What is gastrin?
Ans. Gastrin is the hormones produced by mucosa of the pyloric region of the stomach. It stimulates the secretin of gastric juice, It is produced under the influence of protein food in the stomach after it is partially digested.
Q 117. What is Secretin?
Ans. It is produced from the duodenum when acid food touches its lining. It affects the pancreas to produce and release pancreatic juice and also affects the rate of bile production, in the liver.
Q 118. Where oestrognes and progesterone are produced?
Ans. Oestrognes are secreted by ripening follicles whose development has been initiated by FSH from the pituitary.
Progesterone is produced by the ruptured follicle in response to LH from the pituitary.
Q 119. What are seminiferous tubules and interstitial cells?
Ans. The testes consists of many coiled seminiferious tubules where the spermatozoa develop and, between the tubules, regions of interstitial cells which produced gonadal hormones called Testosterone and 17 B-hydroxytestosterone.
Q 120. Define feedback mechanism?
Ans. It is a type of interaction in which a controlling mechanism itself controlled by the products of reactions it i controlling.
Q 121. What is behaviour?
Ans. Behaviour is defined as a change in response to stimulus. In other words animal behaviour is the sum of every thing that animals do, i.e flying, walking, sitting, sleeping, eating, mating, rearing young ones, etc.
Q 122. what is the Innate Behaviour?
Ans. It is a collection of responses that are predetermined by the inheritance of specific nerve or cytoplasmic pathways in multicelluar or unicellular (acellular) organisms. All plant behvaiour is innate.
Q 123. What are Kineses?
Ans. It is a behaviour in which an organism changes the speed of random movements which help them to survive in the environment e.g., this type of behaviour enables pillpugs to reach the moist area which is required for their life.
Q 124. What are Taxes?
Ans. A taxis (plural: taxes) is a directed movement either towards (positive taxis) or away from (negative taxis) a stimulus.
Q 125. What are instincts?
Ans. According to Darwin, instincts are complex reflexes made up of units compatible with the mechanisms of inheritance, and thus a product of natural selection, that had evolved together with the other aspects of life.
Q 126. Define Learning?
Ans. Learning depends on the experiences in one's own life. Or Thrope defined learning as that process which manifests itself by adaptive changes in individual behaviour as a result of experience.
Q 127. What is innate releasing mechanism (IRM)?
Ans. The selective responses to stimuli suggested that there must be some built-in mechanism by which sign stimuli were recognized. This mechanism came to be called the innate releasing mechanism.
Q 128. What is Imprinting?
Ans. Brief exposure of a organism to the stimulus with long lasting effect is called imprinting. It is best known in birds such as geese, ducks and chickens.
Q 129. Define Habituation?
Ans. Habituation is the simplest form of learning and involves modification of behaviour through a diminution (reduction) of response to repeated stimuli.
Q 130. Define conditioning or conditioned reflex type I?
Ans. Conditioning or conditioned reflex type I involves the pairing of an irrelevant stimulus within a natural primary stimulus that elicits an automatic response.
Q 131. Define Operant conditioning or conditioned reflex type II?
Ans. Under natural conditions the achievement of a particular goal is the reward that directs random activities into a hevaoural pattern, Trial and error repetitions, step by step, lead to final achievement.
Q 132. What is Latent learning?
Ans. Thrope defined latent learning as the association of indifferent stimuli or situations without patent (clear or observable) reward.
Q 133. What is insight learning?
Ans. Insight learning is an extreme case of behavioural modification involving the application of insight (nearby or within reach) or reasoning to a novel (new or unusal) situation.
Q 119. What are seminiferous tubules and interstitial cells?
Ans. The testes consists of many coiled seminiferious tubules where the spermatozoa develop and, between the tubules, regions of interstitial cells which produced gonadal hormones called Testosterone and 17 B-hydroxytestosterone.
Q 120. Define feedback mechanism?
Ans. It is a type of interaction in which a controlling mechanism itself controlled by the products of reactions it i controlling.
Q 121. What is behaviour?
Ans. Behaviour is defined as a change in response to stimulus. In other words animal behaviour is the sum of every thing that animals do, i.e flying, walking, sitting, sleeping, eating, mating, rearing young ones, etc.
Q 122. what is the Innate Behaviour?
Ans. It is a collection of responses that are predetermined by the inheritance of specific nerve or cytoplasmic pathways in multicelluar or unicellular (acellular) organisms. All plant behvaiour is innate.
Q 123. What are Kineses?
Ans. It is a behaviour in which an organism changes the speed of random movements which help them to survive in the environment e.g., this type of behaviour enables pillpugs to reach the moist area which is required for their life.
Q 124. What are Taxes?
Ans. A taxis (plural: taxes) is a directed movement either towards (positive taxis) or away from (negative taxis) a stimulus.
Q 125. What are instincts?
Ans. According to Darwin, instincts are complex reflexes made up of units compatible with the mechanisms of inheritance, and thus a product of natural selection, that had evolved together with the other aspects of life.
Q 126. Define Learning?
Ans. Learning depends on the experiences in one's own life. Or Thrope defined learning as that process which manifests itself by adaptive changes in individual behaviour as a result of experience.
Q 127. What is innate releasing mechanism (IRM)?
Ans. The selective responses to stimuli suggested that there must be some built-in mechanism by which sign stimuli were recognized. This mechanism came to be called the innate releasing mechanism.
Q 128. What is Imprinting?
Ans. Brief exposure of a organism to the stimulus with long lasting effect is called imprinting. It is best known in birds such as geese, ducks and chickens.
Q 129. Define Habituation?
Ans. Habituation is the simplest form of learning and involves modification of behaviour through a diminution (reduction) of response to repeated stimuli.
Q 130. Define conditioning or conditioned reflex type I?
Ans. Conditioning or conditioned reflex type I involves the pairing of an irrelevant stimulus within a natural primary stimulus that elicits an automatic response.
Q 131. Define Operant conditioning or conditioned reflex type II?
Ans. Under natural conditions the achievement of a particular goal is the reward that directs random activities into a hevaoural pattern, Trial and error repetitions, step by step, lead to final achievement.
Q 132. What is Latent learning?
Ans. Thrope defined latent learning as the association of indifferent stimuli or situations without patent (clear or observable) reward.
Q 133. What is insight learning?
Ans. Insight learning is an extreme case of behavioural modification involving the application of insight (nearby or within reach) or reasoning to a novel (new or unusal) situation.
FSc Notes Biology Part 2 Chapter 19 Growth and Development Short Questions
Q 1. What are growing points?
Ans. In higher plants, growth is limited o certain regions known as growing points e.g., shoot apex and root tip.
Q 2. What is secondary growth?
Ans. The growth of secondary tissues i.e., secondary xylem and phloem, by the intercalary or vascular cambium leading to increase in thickness is called secondary growth.
Q 3. Name the factors by which rate of growth is influenced?
Ans. The growth rate is influenced by number of factors both external and internal. External factor are temperature, light, oxygen, carbon dioxide, etc. While internal factors are hormones, water, vitamins etc.
Q 4. What is correlation?
Ans. The development of a plant is usually correlated with its growth and different organs grow at different rates in different directions and the development of different parts takes place, such reciprocal relationship is known as correlation.
Q 5. What is embryology?
Ans. Embryology is the study of growth and differentiation undergone by an organism in the course of its development from a single fertilized egg into highly complex and an independent living being like his parents.
Q 6. What is discoidal cleavage?
Ans. In bird's egg the process of cell division is confined to the small disc of protoplasm lying on the surface of the yolk at the animal pole. This type of cleavage is referred to as discoidal cleavage.
Q 7. What is the role of cytokinins in apical dominance?
Ans. Cytokinins play important role in apical dominance and in many cases if cytokinins is applied directly on the inhibited bud, it allows lateral buds to be released from apical dominance.
Q 8. Which process is defined as negative physiological changes?
Ans. Aging can be defined as negative physiological changes in our body.
Q 9. Due to what factors normal process of development is disturbed?
Ans. The normal process of development is disturbed by abnormalities inherited from parents, abnormalities due to chromosomes or genes, environmental factors or metabolic defects.
Q 10. Define embryonic induction?
Ans. The influence of notochordal cells on he ectodermal cells to become nervous system was called embryonic induction by Spemann.
Q 11. Differentiate between growth and development?
Ans. Growth is the permanent and irreversible increase in size that occurs as an organism matures. While the progressive changes which are undergone before an organism become adult, constitute embryonic development.
Q 12. What is meristem?
Ans. Meristems are young tissues or population of cells that retain the potential to divide.
Q 13. What is open growth?
Ans. A plant has a growth pattern called open growth because throughout life, the plant adds new organs, such as branches, leaves and roots, enlarging from the tips of roots and shoots.
Q 14. What is Apical Meristem?
Ans. The apical meristems are found at the tips of roots and shoot and are primarily concerned with the extension of plant body. These are perpetual growth zones found at the apices of roots and stems. They play important role in primary growth.
Q 15. What are Intercalary Meristems?
Ans. These are the parts of apical meristem which get separated from apex by permanent tissues. They are situated at the bases of internodes in many plants. they play important role in the production of leaves and flower. These are of temporary nature.
Q 16. What are Lateral meristems?
Ans. Lateral Meristems are cylinders of dividing cells present in dicots and gymnosperms. Vascular and cork cambium are the examples of lateral meristems. They play an important role in he increases in diameter of stem and root and are involved in secondary growth.
Q 17. Define differentiation?
Ans. Differentiation is the formation of specialized tissues.
Q 18. What was the work of Thimann and Skoog?
Ans. Thimann and Skoog in 1934 performed experiments and showed that apical dominance was caused by auxin diffusing from the apical bud.
Q 19. Differentiate between inhabitory and compensatory effects?
Ans. Auxin released from apical bud inhibited the growth of lateral shoots or buds and it is called inhibitory effect. While the removal of apex releases the lateral buds from apical dominance. It is called compensatory effect.
Q 20. What is the temperature for incubation for chick egg?
Ans. In incubating eggs artificially, the incubators are usually regulated at temperature between 36-38 degree centigrade. At this temperature, the chick completes development and is hatched on the twenty first day.
Q 21. Define Cleavage?
Ans. The egg undergoes a series of mitotic divisions, called cleavage.
Q 22. What is Morula?
Ans. Cleavage results in the formation of a rounded closely packed mass of blastomeres. This is morula.
Q 23. What is Blastula?
Ans. The morula stage is short lived and soon changes into blastula and is characterized by the presence of a segmentation cavity or blastocoele.
Q 24. what is blastoderm?
Ans. The discoidal cap of cells above the blastocoele is called blastoderm.
Q 25. What is zone of junction in developing chick embryo?
Ans. The marginal area of the blastoderm in which the cells remain undetached from the yolk and closely adherent (supporting) to it, is called the zone of junction.
Q 26. Define Gastrulation?
Ans. It is characterized by the movement and rearrangement of cells in the embryo.
Q 27.Which two layers are formed from blastoderm during gastrulation?
Ans. During gastrulation the blastoderm splits into two layers: an upper layer of cells called epiblast, and a lower layer of cells called hypoblast.
Q 28. What is area pellucida?
Ans. The central cells of blastoderm can be separated from the yolk, under these central cells a pool of fluid develops, raising them off the yolk and giving the area a translucent appearance - the area pellucida.
Q 29. What is area opaca?
Ans. The peripheral part of the blastoderm where the cells lie unseparated from the yolk is termed as area opaca.
Q 30. What is Primitive streak?
Ans. In the chick the mesodermal cells migrate medially and caudally from both sides create a mid line thickening called primitive streak. The primitive streak represents the dorsal and both lateral lips of blastopore.
Q 31. What is primitive node?
Ans. The anterior end of the primitive streak is occupied by an aggregation - the primitive node or notochordal cells while res of cells are mesodermal cells.
Q 32. What is Hensen's node?
Ans. At the cephalic end of primitive streak, closely packed cells form a local thickening known as Hensen's node.
Q 33. What is Germ wall?
Ans. In sections of embryo incubated from 18-20 hours, it is seen that ectoderm has spread and become organized into a coherent layer of cells merging peripherally with the yolk and the marginal area where the expanding germ layers merge with the under lying yolk is known as germ wall.
Q 34. What is gastrocoele?
Ans. The cavity of the gastrula is called gastrocoele.
Q 35. How many layers, the lateral plate mesoderm is split-ted into?
Ans. The lateral plate mesoderm is split-ted into two sheet like layers viz Somatic mesoderm and Splanchnic mesoderm with a space between them.
Q 36. What is coelom?
Ans. The cavity formed between somatic and splanchnic mesoderm is coelom.
Q 37. What is Neurula?
Ans. The whole process of formation of nervous system is called neurulation.
Q 38. How neural plate is formed?
Ans. On the dorsal surface of gastrula, over the notohchord, presumptive neural ectoderm is present in the form of a band. As gastrula elongates, the band thickens to form a neural plate.
Q 39. What is Neurula?
Ans. In 24 hour chick embryos, the folding of neural plate is clearly visible. The embryo is now termed as neurula.
Q 40. How neural tube is formed in chick embryo?
Ans. The neural plate sinks and the neural folds grow toward one anther and meat in the mid-dorsal line, fuse and convert the neural groove into neural tube.
Q 41. What are neuropores?
Ans. At each end of neural tube, a small opening called anterior and posterior neuropores are also seen, which close later on.
Q 42. What is neurocoel?
Ans. With the formation of neural tube, there is formation of central nervous system and the cavity enclosed is known as neurocoel.
Q 43. What was work of Dietrich?
Ans. In 1892, Hans Dietrich, took sea urchin egg at two-cell stage, shook it apart and separated it into two cells. Later on, it was seen that both half embryos developed into normal larvae.
Q 44. What is Acetabularia?
Ans. It is multicellular alga. It consists of rhizoid, which is attached to the grounds, from which arises a long talk with an umbrella shaped cap at its top. Two species of Acetabularia have been identified; Acetabularia mediterranea and A. crenulata.
Q 45. What is primary induction?
Ans. Spemann designated the dorsal lip area the primary organizer because it was the only tissue capable of inducing development of secondary embryo in the host. This was called primary induction.
Q 46. Define regeneration?
Ans. The ability to regain or recover the lost or injured part of the body is called regeneration.
Q 47. What are neoblasts?
Ans. In flatworms, and Planaria the unspecialized cells, called, neoblasts, are always present in the body of adult and are mobilized and migrate to the site of amputation (cut off), where they differentiate into specialized cell types.
Q 48. Define abnormal development?
Ans. Sometimes, under unfavourable conditions, some parts of the body do not develop normally and this is called abnormal development.
Q 49. Define Teratology?
Ans. Teratology is the branch of biology, which deals with these abnormal development and causes for such developments.
Q 50. How normal process of development is disturbed?
Ans. How normal process of development is disturbed:
- abnormalities Inherited from parents,
- abnormalities due to chromosomes or genes,
- environmental factors,
- metabolic defects.
Q 51. What are Teratogens?
Ans. Environmental factors causing or contributing to abnormal development are grouped together as teratogens e.g., ionizing radiations such as X rays.
Q 52. What is Microcephaly?
Ans. It is a defect in which the Individuals are born with small skull.
Q 53. What is Cleft palate?
Ans. It is an abnormality in which individuals have their upper lips folded or the individual has harelip.
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