NEET AIPMT Biology Chapter Wise Solutions – Structural Organisation in Animals
Contents
NEET AIPMT Biology Chapter Wise SolutionsPhysicsChemistry
1. The body cells in cockroach discharge their nitrogenous waste in the haemolymph mainly in the form of (AJPMT 2015)
(a) urea
(b) calcium carbonate
(c) ammonia
(d) potassium urate.
2. The function of the gap junction is to (AIPMT 2015)
(a) separate two cells from each other
(b) stop substance from leaking across a tissue
(c) performing cementing to keep neighbouring cells together
(d) facilitate communication between adjoining cells by connecting the cytoplasm for rapid transfer of ions, small molecules and some large molecules.
3. The terga, sterna and pleura of cockroach body are joined by (AIPMT 2015, Cancelled)
(a) arthrodial membrane
(b) cartilage
(c) cementing glue
(d) muscular tissue.
4. Choose the correctly matched pair. (AIPMT 2014)
(a) Tendon – Specialized connective tissue.
(b) Adipose tissue – Dense connective tissue.
(c) Areolar tissue – Loose connective tissue.
(d) Cartilage – Loose connective tissue.
5. Choose the correctly matched pair. (AIPMT 2014)
(a) Inner lining of – Ciliated epithelium salivary ducts
(b) Moist surface – Glandular epithelium of buccal cavity
(c) Tubular parts of – Cuboidal epithelium nephrons
(d) Inner surface of – Squamous epithelium bronchioles
6. What external changes are visible after the last moult of a cockroach nymph? (NEET 2013)
(a) Both fore wings and hind wings develop
(b) Labium develops
(c) Mandibles become harder
(d) Anal cerci develop.
7. Select the correct option with respect to cockroaches. (Karnataka NEET 2013)
(a) Malpighian tubules convert nitrogenous wastes into urea.
(b) Males bear short anal styles not present in females.
(c) Nervous system comprises of a dorsal nerve cord and ten pairs of ganglia.
(d) The forewings are tegmina which are used in flight.
8. Identify the tissue shown in the diagram and match with its characteristics and its locatio (Karnataka NEET 2013)
(a) Smooth muscles, show branching, found in the wall of the heart.
(b) Cardiac muscles, unbranched muscles, found in the walls of the heart.
(c) Striated muscles, tapering at both-ends, attached with the bones of the ribs.
(d) Skeletal muscles show striations and are closely attached with the bones of the limbs.
9. Compared to those of humans, the erythrocytes in frog are (Prelims 2012)
(a) without nucleus but with haemoglobin
(b) nucleated and with haemoglobin
(c) very much smaller and fewer
(d) nucleated and without haemoglobin.
10. Select the correct statement from the ones given below with respect to Periplaneta americana, (Prelims 2012)
(a) Nervous system located dorsally, consists of segmentally arranged ganglia joined by a pair of longitudinal connectives.
(b) Males bear a pair of short thread like anal styles.
(c) There are 16 very long Malpighian tubules present at the junctions of midgut and hindgut.
(d) Grinding of food is carried out only by the mouth parts.
11. Given below is the diagrammatic sketch of a certain type of connective tissue. Identify the parts labelled A, B, C and D, and select the right option about them (Mains 2012)
12. The supportive skeletal structures in the human external ears and in the nose tip are examples of (Mains 2012)
(a) ligament
(b) areolar tissue
(c) bone
(d) cartilage.
13. The four sketches (A, B, C and D) given below, represent four different types of animal tissues. Which one of these is correctly identified in the options given, along with its correct location and function?
14. The ciliated columnar epithelial cells in humans are known to occur in (Prelims 2011)
(a) Eustachian tube and stomach lining
(b) bronchioles and Fallopian tube
(c) bile duct and oesophagus
(d) Fallopian tube and urethra.
15. One very special feature in the earthworm (Pheretima) is that (Prelims 2011)
(a) fertilization of eggs occurs inside the body
(b) the typhlosole greatly increases the effective absorption area of the digested food in the intestine
(c) the S-shaped setae embedded in the integument are the defensive weapons used against the enemies
(d) it has a long dorsal tubular heart.
16. Which of the following happens in the common i cockroach? (Prelims 2011)
(a) Malpighian tubules are excretory organs projecting out from the colon
(b) Oxygen is transported by haemoglobin in blood
(c) Nitrogenous excretory product is urea
(d) The food is ground by mandibles and gizzard.
17. Frogs differ from humans in possessing (Mains 2011)
(a) paired cerebral hemispheres
(b) hepatic portal system
(c) nucleated red blood cells
(d) thyroid as well as parathyroid.
18. The cells lining the blood vessels belong to the category of (Mains 2011, Prelims 2010)
(a) smooth muscle tissue
(b) squamous epithelium
(c) columnar epithelium
(d) connective tissue.
19. Which one of the following structures in Pheretima is correctly matched with its function? (Mains 2011)
(a) clitellum – secretes cocoon
(b) gizzard – absorbs digested food
(c) setae – defence against predators
(d) typhlosole – storage of extra nutrients.
20. Which one of the following pairs of structures is correctly matched with their corrected description? (Mains 2010)
21. Which one of the following correctly describes the location of some body parts in the earthworm Pheretima? (Prelims 2009)
(a) four pairs of spermathecae in 4-7 segments
(b) one pair of ovaries attached at intersegmental septum of 14th and 15th segments
(c) two pairs of testes in 10th and 11th segments
(d) two pairs of accessory glands in 16-18 segments
22. Which one of the following is correct pairing of a body part and the kind of muscle tissue that moves it? (2009)
(a) biceps of upper arm – smooth muscle fibe
(b) abdominal wall – smooth muscle
(c) iris – involuntary smooth muscle
(d) heart wall – involuntary unstriated muscle
23. The epithelial tissue present on the inner surface of bronchioles and Fallopian tubes is (2009)
(a) glandular
(b) ciliated
(c) squamous
(d) cuboidal
24. The cell junctions called tight, adhering and gap junctions are found in (2009)
(a) connective tissue
(b) epithelial tissue
(c) neural tissue
(d) muscular tissue
25. The kind of tissue that forms the supportive structure in our pinna (external ears) is also found in (2009)
(a) nails
(b) ear ossicles
(c) tip of the nose
(d) vertebrae
26. Earthworms have no skeleton but during burrowing, the anterior end becomes turgid and acts as a hydraulic skeleton. It is due to (Prelims 2008)
(a) gut peristalsis
(b) setae
(c) coelomic fluid
(d) blood.
27. Which one ofthe following is the true description about an animal concerned? (Prelims 2008)
(a) rat – left kidney is slightly higher in position than the right one
(b) cockroach – 10 pairs of spiracles (2 pairs on thorax and 8 pairs on abdomen)
(c) earthworm – the alimentary canal consists of a sequence of pharynx, oesophagus, stomach, gizzard and intestine
(d) frog – body divisible into three regions – head, neck and trunk.
28. Which one of the following pairs of structures distinguishes a nerve cell from other types of cell? (2007)
(a) vacuoles and fibres
(b) flagellum and medullary sheath
(c) nucleus and mitochondria
(d) perikaryon and dendrites.
29. In which one of the following preparations are 37 you likely to come across cell junctions most frequently? (2007)
(a) thrombocytes
(b) tendon
(c) hyaline cartilage
(d) ciliated epithelium.
30. Areolar connective tissue joins
(a) bones with bones
(b) fat body with muscles
(c) integument with muscles
(d) bones with muscles
31. Mast cells secrete (2006)
(a) haemoglobin
(b) hippurin
(c) myoglobin
(d) histamine
32. Earthworms are (2006)
(a) ammonotelic when plenty of water is available
(b) ureotelic when plenty of water is available
(c) uricotelic when plenty of water is available
(d) uricotelic under conditions of water scarcity
33. Four healthy people in their twenties got involved in injuries resulting in damage and death of few cells of the following. Which of the cells are least likely to be replaced by new cells? (2005)
(a) liver cells
(b) neurons
(c) malpighian layer of the skin
(d) osteocytes.
34. Mast cells of connective tissue contain (2004)
(a) vasopressin and relaxin
(b) heparin and histamine
(c) heparin and calcitonin
(d) serotonin and melanin.
35. Which one of the following contains the largest quantity of extracellular material ? (2003)
(a) striated muscle
(b) areolar tissue
(c) stratified epithelium
(d) myelinated nerve fibres
36. Collagen is (2002)
(a) fibrous protein
(b) globular protein
(c) lipid
(d) carbohydrate.
37. Melanin protects from (2002)
(a) U.V. rays
(b) visible rays
(c) infrared rays
(d) X-rays.
38. During an injury nasal septum gets damaged and for its recovery which cartilage is preferred? (2001)
(a) elastic cartilage
(b) hyalin cartilage
(c) calcified cartilage
(d) fibrous cartilage.
39. Which cells do not form layer and remains structurally separate? (2001)
(a) epithelial cells
(b) muscle cells
(c) nerve cells
(d) gland cells.
40. Proteoglycan in cartilages which is a part of polysaccharide is (2000)
(a) chondroitin
(b) ossein
(c) casein
(d) cartilagin.
41. Characteristic of simple epithelium is that they (2000)
(a) are arranged indiscriminately
(b) make a definite layer
(c) continue to divide and help in organ function
(d) none of the above.
42. Which pair is correct? (2000)
(a) sweat = temperature regulation
(b) saliva = sense of food taste
(c) sebum = sexual attraction
(d) humerus = hind leg.
43. Primary function of enteronephric nephridia of Pheretima is (2000)
(a) osmoregulation
(b) excretion of nitrogenous wastes
(c) respiration
(d) locomotion.
44. Ligament is a/an (1999)
(a) inelastic white fibrous tissue
(b) modified white fibrous tissue
(c) modified yellow elastic fibrous tissue
(d) none of the above.
45. Tendon is made up of (1999)
(a) yellow fibrous connective tissue
(b) modified white fibrous tissue
(c) areolar tissue
(d) adipose tissue.
46. In mammals, histamine is secreted by (1998)
(a) lymphocytes
(b) mast cells
(c) fibroblasts
(d) histiocytes.
47. Protein present in cartilage is (1997)
(a) cartilagin
(b) ossein
(c) chondrin
(d) none of these.
48. Basement membrane is made up of (1997)
(a) no cell product of epithelial cell
(b) epidermal cell only
(c) endodermal cell
(d) both (b) and (c).
49. Stratum germinativum is an example of which kind of epithelium? (1997)
(a) columnar
(b) squamous
(c) cuboidal
(d) ciliated.
50. The roof of the cranium of frog is formed by (1997)
(a) frontoparietal
(b) orbitosphenoid
(c) parasphenoid
(d) ali sphenoid.
51. In frog, the surface of attachment of tongue is (1997)
(a) pterygoid
(b) hyoid apparatus
(c) parasphenoid
(d) palatine.
52. In frog, “fenestra ovalis” is (1997)
(a) the communication between the pharynx and the tympanic cavity
(b) the external opening of the tympanic cavity which is covered by the tympanic membrane
(c) the air filled cavity of the middle ear
(d) the opening in the auditory capsule which separates the middle ear from the internal ear.
53. The kidney of an adult frog is (1997)
(a) metanephros
(b) opisthonephros
(c) pronephros
(d) mesonephros.
54. An epithelial tissue which has thin flat cells, arranged edge to edge so as to appear like closely packed tiles, is found to be present at (1994)
(a) outer surface of ovary
(b) inner lining of fallopian tube
(c) inner lining of stomach
(d) inner lining of cheeks.
55. Hair present in the skin are (1993)
(a) epidermal in origin and made of dead cells
(b) epidermal in origin and made of living cells
(c) dermal in origin and made of living cells
(d) dermal in origin and made of dead cells.
56. The layer of actively dividing cells of skin is termed as (1993)
(a) Stratum compactum
(b) Stratum comeum
(c) Stratum malpighii/stratum germinativum
(d) Stratum lucidum.
57. Formation of cartilage bones involves (1993)
(a) deposition of bony matter by osteoblasts and resorption by chondroclasts
(b) deposition of bony matter by osteoclasts
(c) deposition of bony matter by osteoclasts only
(d) deposition of bony matter by osteoblasts only.
58. Mucus helps frog in forming (1993)
(a) thick skin
(b) dry skin
(c) smooth skin
(d) moist skin.
59. Characteristics of smooth muscle fibres are (1992)
(a) spindle-shaped, unbranched, nonstriated, uninucleate and involuntary
(b) spindle-shaped, unbranched, unstriped, multinucleate and involuntary
(c) cylindrical, unbranched, unstriped, multinucleate and involuntary
(d) cylindrical, unbranched, striated, multinucleate and voluntary.
60. Male and female cockroaches can be distinguished externally through (1991)
(a) anal styles in male
(b) anal cerci in female
(c) anal style and antennae in females
(d) both B and C.
61. Earthworm possesses hearts (1991)
(a) 6 pairs
(b) 4 pairs
(c) 2 pairs
(d) 1.
62. Blood of Pheretima is (1990)
(a) blue with haemocyanin in corpuscles
(b) blue with haemocyanin in plasma
(c) red with haemoglobin in corpuscles
(d) red with haemoglobin in plasma.
63. Pheretima posthuma is highly useful as (1990)
(a) their burrows make the soil loose
(b) they make the soil porous, leave their castings and take organic debris in the soil
(c) they are used as fish meal
(d) they kill the birds due to biomagnification of
chlorinated hydrocarbons.
64. Haversian canals occur in (1989)
(a) humerus
(b) pubis
(c) scapula
(d) clavicle.
65. Histamine secreting cells are found in (1989)
(a) connective tissues
(b) lungs
(c) muscular tissue
(d) nervous tissue.
66. Mineral found in red pigment of vertebrate blood is (1989)
(a) magnesium
(b) iron
(c) calcium
(d) copper.
67. Photoreceptors of earthworm occur on (1989)
(a) clitellum
(b) many eyes
(c) dorsal surface
(d) lateral sides.
Explanations
1. (d)
In cockroach, Malpighian tubules extract metabolic wastes like potassium and sodium urate, water and carbon dioxide from the blood. In the Malpighian ‘ tubules bicarbonates of potassium and sodium, water and I uric acid are formed. A large amount of water and bicarbonates of potassium and sodium are reabsorbed by the cells of Malpighian tubules and then transferred to the blood (haemolymph). Uric acid is carried to the alimentary canal of the insect and is finally passed out through anus.
2. (d)
Most cells in animal tissues (with the exception of a few terminally differentiated cells such as skeletal muscle cells and blood cells) are in communication with their adjoining cells via gap junctions. At the place where gap junction is present, membranes of two adjacent cells are separated by a uniform narrow gap of about 2-4 nm. 1 The gap is spanned by channel forming proteins called connexins, which allow inorganic ions, and other small water soluble molecules to pass directly from cytoplasm of one cell to cytoplasm of other cell.
3. (a)
Arthrodial membrane is a tough, flexible cuticle that joins the skeletal elements of cockroach and other arthropods. It connects terga, pleura and sterna of cockrocah body.
4. (c)
Areolar tissue is the most widely distributed loose connective tissue in the body. Tendon is a type of dense connective tissue, adipose tissue is a fat¬storing loose connective tissue and cartilage is a specialised connective tissue.
5. (c)
Inner lining of – Simple cuboidal epithelium salivary ducts
Moist surface of – Non-keratinized stratified buccal cavity squamous epithelium.
Inner surface – Ciliated columnar epithelium, of bronchioles
6. (a)
Cockroach undergoes paurometabolous development. The nymph moults about 6-7 times to reach the adult form. The next to last nymphal stage has wing pads but only adult cockroaches have wings.
7. (b)
Malpighian tubules are the main excretory structures in cockroach. They extract nitrogenous wastes and water from haemolymph and reabsorb certain salts resulting in precipitation of uric acid. So, cockroach is uricotelic. Males have paired anal styles on 9th abdominal stemite which are absent in females.
8. (d)
Locomotion (performed by limbs) in humans depends on the movements of muscle fibres. Skeletal muscles are attached to the bones by tendons and help in the movement of the parts of skeleton. These muscles are under the control of conscious mind and are called voluntary muscles. Under the microscope, these muscles show transverse stripes and hence are designated as striated muscles.
9. (b)
Human erythrocytes are enucleated, discoidal while in frogs erythrocytes are large, oval and biconvex nucleated cells. Erythrocytes are the carriers of haemoglobin.
10. (b)
The posterior segment of cockroaches bear appendages named as anal cerci. These are found in both male and female. But male cockroach can be distinguished by female ones by the presence of an extra pair of accessory appendages named as anal styles. It assists during copulation.
11. (a)
12. (d)
Cartilage is a semi-rigid supportive or skeletal connective tissue in which matrix is solid and made of mucoprotein or proteoglycan called chondrin. It is of four types -hyaline, fibrous, calcified and elastic. Yellow elastic fibrocartilage is found in pinna and external auditory canal of the ear, Eustachian tubes, epiglottis and tip of the nose. Its matrix contains numerous yellow fibres which fornetwork by uniting with one another. Due to the presence of yellow fibres, the cartilage becomes more flexible. Hence, it provides flexibility to these organs.
13. (a)
Intestine is lined by glandular epithelium which is secretory in function. The glands found in intestine are exocrine and may be unicellular or multicellular. When unicellular glands secrete mucus, they are Called mucus cells or goblet cells and are common in the columnar epithelium of intestine. When unicellular glands secrete a clear watery fluid, they are called serous cells which are also present in intestinal glands. On the other hand, multicellular glands consist of a duct and secretory portion, both formed of epithelial cells. They are further of two types: tubular and saccular. In tubular glands secretory portion is tube like for example, Crypts of Lieberkuhn (a type of simple straight tubular glands found in intestine) and Brunner’s gland (a type of simple branched tubular glands found in intestine),
14. (b)
The ciliated columnar epithelial cells in humans are present in the nasal passages, oviducts (Fallopian tubes) terminal bronchioles, ventricles of the brain and central canal of the spinal cord of the embryo. Columnar ciliated , epithelium consists of columnar cells, which bear cilia on the free surface.
15. (b)
In Pheretima, next to stomach is the intestine. It is a long, wide and thin walled tube extending from 15th segment to the last. Second or middle part of the intestine f lies between 27th segment upto 23-25 segments in front of anus. This is characterised by the presence of a highly glandular and vascular longitudinal ridge, arising as a , median in-growth of the dorsal aspect of the intestinal cavity. This is called the typhlosole. The typhlosole greatly increases the effective absorption area of the digested food in the intestine.
16. (d)
Mouth part of cockroach contain two mandibles, which bears teeth. When both the mandibles work simultaneously in a horizontal plane, the food matter is cut and masticated into fine and smaller pieces. Gizzard is a part of alimentary canal. It bears six muscular folds which are covered by chitinous conical plates, the teeth, used for grinding the food.
17. (e)
Human erythrocytes are enucleated, discoidal while in frogs erythrocytes are large, oval and biconvex nucleated cells. Erythrocytes are the carriers of haemoglobin.
18. (b)
‘Simple squamous epithelium is composed of large flat cells whose edges fit closely together like the tiles in a floor, hence it is also called pavement epithelium. The nuclei of the cells are flattened and often lie at the centre of the cells and cause bulgings of cells surface. The epithelium lines the blood vessels, lymph vessels, heart, terminal bronchioles, alveoli of the lungs, walls of the Bowman’s capsules, descending limbs of loop of Henle. In the blood vessels and heart it is called endothelium.
19. (a)
In a mature earthworm, segments 14-16 are covered by a prominent dark band of glandular tissues called clitellum which secretes cocoon where fertilization and development takes place. In alimentary canal, muscular gizzard (8-9 segments) helps in grinding the soil particles and decaying leaves etc. The characteristic feature of the intestine between 26-35 segments is the presence of internal median fold of dorsal wall called typhlosole. This increases the effective area of absorption in the intestine. In each body segment, except the first, last and clitellum, there are rows of S-shaped setae, embedded in the epidermal pits in the middle of each segment. Setae can be extended or retracted. Their principal role is in locomotion.
20. (b)
Cartilage is avascular, as the blood vessels innervate only perichondrium through which nutrition diffuses into cartilage cells. Cornea is also avascular.
21. (c)
In Pheretima two pairs of testis sac are situated in the tenth and eleventh segments. Each testis sac of the tenth segment encloses a testis and a seminal funnel. Each testis sac of the eleventh segment encloses a testis, a seminal vesicle and a seminal funnel.
22. (c)
Smooth muscles are called as involuntary muscles as action of these muscles is controlled by autonomic nervous system i.e. not under the control of animal’s will. Iris of eyes consist of smooth involuntary muscles. Abdominal wall also have smooth muscles. Biceps of upper arm is made of skeletal muscles while heart wall consists of cardiac muscles.
23. (b)
The ciliated columnar epithelial cells in humans are present in the nasal passages, oviducts (Fallopian tubes) terminal bronchioles, ventricles of the brain and central canal of the spinal cord of the embryo. Columnar ciliated , epithelium consists of columnar cells, which bear cilia on the free surface.
24. (b)
Epithelial tissues consist of variously shaped cells closely arranged in one or more layers. The cells are held together by intercellular junctions like tight, adhering and gap junctions.
25. (c)
Yellow elastic fibrocartilage, a type of skeletal tissue, is found in the pinna, Eustachian tubes, epiglottis and tip of the nose. It is a type of cartilage and due to presence of yellow fibres, it becomes more flexible.
26. (c)
Hydraulic skeleton is the system of support found in soft bodied invertebrates, which relies on the incompressibility of fluids contained within the body cavity. In earthworms the coelomic fluid is underpressure within the coelom and therefore provides support for internal organs. Due to hydraulic skeleton, during burrowing, the anterior end becomes turgid and aids in relaxation of longitudinal muscles.
27. (b)
There are 10 pairs of spiracles in cockroach. Two pairs are thoracic in which first pair is known as mesothoracic, lying infront of the mesothorax between the bases of first and second pair of legs and are the largest. The second pair is called metathoracic. Abdominal spiracles are eight pairs. The first pair is dorsal in position and lies on the lateral margins of the first abdominal tergum. The remaining are situated on the sides of their corresponding segments on the pleura between the terga and sterna. Spiracles are meant for intake of fresh air and release of foul air.
28. (d)
Neuron (nerve cell) is one of the basic functional units of the nervous system. Neuron is a cell specialized to transmit electrical nerve impulse and so carry information from one part of the body to another. Each neuron has an enlarged portion, the cell body (perikaryon), containing the nucleus; from the body extend several processes (dendrites) through which impulses enter from their branches. A longer process, the nerve fibre, extends outward and carries impulses away from the cell body. This is normally unbranched except at the nerve ending. The point of contact of one neuron with another is known as a synapse.
29. (d)
From the given four options cell junctions come across most frequently in the preparation of ciliated epithelium. A cell junction is a structure within a tissue of a multicellular organism. Cell junctions are especially abundant in epithelial tissues. They consist of protein complexes and provide contact between neighbouring cells, between a cell and the extracellular matrix, or they built up the paracellular barrier of epithelia and control the paracellular transport. Ciliated epithelium is a region of epithelium consisting of columnar or cuboidal cells bearing hairlike appendages that are capable of beating rapidly. Ciliated epithelium performs the function of moving particles or fluid over the epithelial surface in such structures as the trachea, bronchial tubes, and nasal cavities. It often occurs in the vicinity of mucus-secreting goblet cells. The other three (thrombocytes, tendon and hyaline cartilage) belongs to connective tissue. Connective tissue is widely distributed and has many functions including support, packing, defence and repair. Thrombocytes or platelets aid the formation of blood clots by releasing various protein substances. Tendon attaches a muscle to a bone and hyaline cartilage consists largely of glycosaminoglycan, giving a shiny glass like appearance and gives flexibility and support at the joints.
30. (c)
Areolar tissue is a loose connective tissue comprised of a semifluid ground substance containing several kinds of loosely arranged fibres. Its function is to attach the skin to the underlying tissues, to fill the spaces between various organs and thus holds them in place, and surrounds and supports the blood vessels. Tendons connect muscles with bone while ligaments connect bone with bone.
31. (d)
Mast cells are granulated wandering cells that are found in connective tissue. Their granules contain histamine which is a vasodilator. It causes running nose, sneezing and itching; and narrows the airways in the lungs. Haemoglobin and myoglobin are the pigments present in the blood and muscles respectively.
32. (a)
Earthworm has excretory organ called nephridia. Ammonia is the chief excretory waste when water is available and hence it is ammonotelic in water and terrestrial earthworm is ureotelic.
33. (b)
Neurons are least likely to be replaced by new cells as they have least regeneration power. Osteocytes are the bone forming cells. Liver cells and Malpighian layer of the skin have regeneration power.
34. (b)
Mast cells are the large cells with densely granular cytoplasm that is found in connective tissues. Their granules contain histamine which is a vasodilator, heparin which is an anticoagulant and serotonin which acts as a mediator of inflammation and allergic reactions. Vasopressin is a hormone secreted by posterior pituitary gland. Calcitonin is a hormone secreted by thyroid gland. Melanin is a pigment produced by specialized epidermal cells called melanocytes. Relaxin is a hormone produced by the corpus luteum and placenta during the terminal stages of pregnancy.
35. (b)
In areolar tissue, there is more intercellular space, so largest quantity of extracellular material is present in this tissue. It contains all cell types and fibres of connective tissue. There is a thin layer of extracellular fluid in stratified epithelium whereas striated muscle is attached with tendons and there is very less amount of extracellular fluid in myelinated nerve fibre.
36. (a)
Collagen is an insoluble fibrous ptotein found extensively in the connective tissue of skin, tendons and bone. Collagen accounts for over 30% of the total body protein of mammals. Globular proteins have compact rounded molecules and are usually water soluble. Lipid is a diverse group of organic compounds, that are insoluble in water but soluble in organic solvents. Carbohydrates are compounds of carbon, hydrogen and oxygen.
37. (a)
Melanin is produced by specialized epidermal cells called melanophores (or melanocytes). Their dispersion in these cells is controlled by melanocyte – stimulating hormone and melatonin. Melanin, a pigment present in skin, protects it from harmful effects of UV rays. People living in tropics have more melanin in their skin which is an adaptation to protect themselves from harmful UV rays. Melanin cannot protect from infrared rays and X-rays.
38. (b)
Nasal septum consists of hyaline cartilage. It is bluish-green and translucent in appearance. It has fewer very fine white fibres in the matrix. This type of cartilage gives flexibility and support at the joints. Elastic, calcified and fibrous cartilages occur in other parts of body.
39. (c)
Nerve cells are the highly excitable cells, specialized for impulse conduction. They originate from neural plate of embryonic ectoderm and serve as structural and functional units of nervous tissue.
40. (a)
Proteoglycans consist of polysaccharide attached with a protein chondroitin. It is present in cartilage as well as in extracellular material. Ossein is a protein present in matrix ofbone. Casein is a milk protein.
41. (b)
Simple epithelium consists of a single layer of cells resting on a basement membrane. This makes a definite layer.
42. (a)
Sweat is secreted by sweat glands of skin and helps in regulating body temperature. Saliva is secreted by salivary glands and helps in digestion (carbohydrate digestion). Sebum is the waxy secretion secreted by sebaceous glands. Sebum is a fatty mildly antiseptic material that protects, lubricates, and waterproofs the skin and hair and helps prevent desiccation. Humerus is the long bone of the upper arm. It articulates with the scapula at the glenoid cavity and with the ulna and radius at the elbow.
43. (a)
Pharyngeal nephridia and septal nephridia are enteronephric as they discharge excretory matter into the gut. Discharge of waste matter via gut is an adaptation to conserve water by its reabsorption in the gut. Integumentary nephridra are exonephric, as they discharge waste matter to the exterior.
44. (c)
Ligament occurs in the form of cords in a modified yellow elastic fibrous tissue and connects bone with a bone. Modified white fibrous tissue is present in the tendons.
45. (b)
White fibrous tissue has two forms : cords and sheets. The white fibres run parallel to form cords, called tendons. Tendon attaches a muscle to a bone. It consists of collagen fibres and are therefore inelastic. They ensure that the force exerted by muscular contraction is transmitted to the relevant part of the body to be moved. Yellow elastic tissue also has two forms : cords and sheets. Here, cords are called ligaments. Adipose tissue is a fat storing loose connective tissue. Areolar tissue is the most widely distributed connective tissue in the body.
46. (b)
Mast cells are found in the matrix of areolar connective tissue and secrete histamine (vasodilator), serotonin (vasoconstrictor) and heparin (anticoagulant). These take part in allergic reactions and also help in a body defence. Fibroblasts and histiocytes are also found in the matrix of areolar tissue. Fibroblasts secrete ground substance while histiocytes engulf the microbes, foreign particles and damaged cells. Lymphocytes are the type of leucocytes present in blood and secrete antibodies.
47. (c)
Chondrin is a protein present in the matrix of cartilage. It forms a constituent of a compound called chondrin sulphate. Chondrin sulphate consists of proteoglycans, that is protein chains bonded to long chains of disaccharide hyaluronic acid. Matrix of bone is made up of a protein called ossein.
48. (a)
Basement membrane (basal lamina) is a thin sheet of fibrous proteins that underlies and supports the cells of an epithelium, separating this from underlying tissue. Basement membranes are components of the extracellular matrix (= the viscous watery fluid that surrounds cells in animal tissue) and help to regulate passage of materials between epithelial cells and adjacent blood vessels. Each consists of a framework of collagen fibrils within which are glycosaminoglycans (mucopolysacc harides) and laminins, which are proteins that bind the basement membrane to neighbouring cells via cell adhesion molecules. .
49. (a)
Stratum germinativum (also stratum basale or basal cell layer) is the layer of keratinocytes that lies at the base of the epidermis immediately above the dermis. It consists of a single layer of tall, simple columnar epithelial cells lying on a basement membrane. These cells undergo rapid cell division, mitosis to replenish the regular loss of skin by shedding from the surface. About 25% of the cells are melanocytes, which produce melanin which provides pigmentation for skin and hair.
50. (a)
Fronto-parietals are a pair of long, broad, flattened and membranous bones. They are united along the mid-dorsal line and form the whole roof of cranium. In larval frog, each fronto-parietal occurs into separate frontal and parietal parts, but in adult frog, they become fused to form a single frontoparietal. The entire floor of cranium is covered and strengthened by a large parasphenoid bone.
51. (b)
In adult frog, gills disappear and their skeletal framework is also reduced to form hyoid apparatus. It lies below tongue in the floor of mouth and provides surface of attachment to the tongue. Pterygoid contributes to the postero-ventral margin of orbit of its side. Palatine connects the anterior side of cranium with the middle of maxilla. Parasphenoid forms floor of the cranium.
52. (c)
The bony partition between tympanic cavity (cavity of middle ear) and auditory capsule (internal ear) is perforated by a small window-like oval aperture, the fenestra ovalis, which remains closed by a membrane and a cartilaginous nodule, the stapedial plate.
53. (d)
Mesonephros kidney is present in both adult as well as embryo of frog. A mesonephros develops from the middle part of intermediate mesoderm, posterior to each pronephros soon after its degeneration.
54. (d)
An epithelial tissue which has thin flat cells, arranged edge to edge so as to appear like closely packed tiles is known as pseudostratified epithelium. It covers moist surfaces where there is little wear and tear by friction such as inner lining of cheeks.
55. (a)
Each hair is present in a tubular pit called hair follicle which is made up by sinking of epidermis. Living cells are present only at the base of hair i.e. in hair papilla, rest of the hair is dead and is divisible into outer cuticle, middle cortex and inner medulla.
56. (c)
Stratum malpighii/stratum germinativum is the innermost layer of the skin consisting of one celled thick columnar epithelial cells. It lies on the basement layer. Its cells are active and continuously produce new cells by mitotic division that is why called germinative layer.
57. (a)
Bone is an unusual tissue in that it is continually being reconstructed. The osteoblasts secrete bone matrix, whereas the large, much branched, motile, lysosome-rich, multinucleate cells, called osteoclasts, destroy bone matrix. The twin process of resorption and resconstruction enables a particular bone to remodel its structure to meet any change in the mechanical requirements of the animal during its development.
58. (d)
Mucus helps frog in forming moist skin as skin is its respiratory organ.
59. (a)
The smooth muscle consists of long, narrow unbranched spindle-shaped fibres. Each fibre contains a single oval nucleus in its thick middle part. The cross- striations are absent so that the fibres look smooth, hence the name nonstriated. Its contraction is not under the control of the animal, therefore, also called involuntary muscle.
60. (a)
In male cockroach, 9th sternum bears a pair of short, unjointed thread-like anal styles which are absent in female. Anal cerci and antennae are present in both male and female cockroaches.
61. (b)
In each of the segments 7, 9, 12 and 13 is found a pair of large, thick, muscular and rhythmically contractile vertical vessels, called hearts. They pump blood from dorsal to ventral vessel, while flow in opposite direction is prevented by internal valves. Hearts of 7th and 9th segments connect dorsal and ventral vessels only and are called lateral hearts. Those of 12th and 13th segments connect both dorsal and supra- oesophageal vessels with ventral vessel, and are designated as latero-oesophageal hearts.
62. (d)
Circulatory or blood vascular system of earthworm is a closed system consisting of blood vessels and capillaries which ramify to all parts of the body. Blood is composed of a fluid plasma and colourless corpuscles, physiologically comparable to the leucocytes of the vertebrates. The red respiratory pigment, haemoglobin (or erythrocruorin) occurs dissolved in plasma. It gives a red colour to blood and aids in the transportation of oxygen for respiration.
63. (b)
Pheretima posthuma is highly useful and beneficial in agriculture. Its habit of burrowing and swallowing earth makes it porous and increases the soil fertility in many ways. Their burrows permit penetration of air and moisture in porous soil and their excretory wastes and other secretions also enrich soil by adding nitrogenous matters to the soil. Pheretima posthuma is not used as fish meal. Whereas a small white earthworm (Enchytraeus albidus) is often grown in soil and used to feed aquarium fish.
64. (a)
Small bones are solid. Long bones, such as the humerus and femur, have a cavity, the marrow cavity, at the centre. The substance of the bone is distinguishable into 3 regions : periosteum, matrix and endosteum. The matrix of bone along with the bone forming cells (osteoblasts) is arranged in concentric layers (lamellae) round the small canals which run parallel to the long axis (shaft) of the bone. These canals, called Haversian canals, are interconnected with one another via Volkmann’s canals and contain a blood vessel, a nerve and a lymph vessel. Bone cells remain alive and once they have completely surrounded by the hard bone matrix, they are called osteocytes. The osteocytes are embedded in fluid-filled cavities within the concentric lamellae. These cavities are known as lacunae and occur at regular intervals in these concentric layers of bone tissue. The lacunae are connected to one another and to the Haversian canals by a system of interconnecting canals known as canaliculi. Each Haversian canal, its concentric lamellae, lacunae with osteocytes and canaliculi forms a long cylinder and is called a Haversian system. Separate Haversian systems are joined to each other by means of interstitial lamellae.
65. (a)
Mast cells are the large cells with densely granular cytoplasm that is found in connective tissues. Their granules contain histamine which is a vasodilator, heparin which is an anticoagulant and serotonin which acts as a mediator of inflammation and allergic reactions. Vasopressin is a hormone secreted by posterior pituitary gland. Calcitonin is a hormone secreted by thyroid gland. Melanin is a pigment produced by specialized epidermal cells called melanocytes. Relaxin is a hormone produced by the corpus luteum and placenta during the terminal stages of pregnancy.
66. (b)
Red pigment of vertebrate blood is haemoglobin. Haemoglobin is a conjugated protein. It consists of a basic protein globin joined to a nonprotein group heme, hence the name haemoglobin. Heme is an iron-porphyrin ring. A mammalian haemoglobin molecule is a complex of 4 heme molecules joined with 4 globin molecules.
67. (c)
Photo-receptors restricted only to dorsal surface, are more numerous on prostomium and peristomium of earthworm and gradually reduce in number towards posterior end of body. They are totally absent in clitellum. Each photoreceptor consists of a single ovoid cell, with a nucleus and clear cytoplasm containing a network of neurofibrillae and a small transparent L-shaped lens or optic organelle or phaosome, made up of a hyaline substance. Photoreceptors enable worms to judge the intensity and duration of light.
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