Brain Grain · braingrain.in
Zoology — Practice Paper · Set 1
Class: 11Samacheer KalviMax Marks: 93
Name: ____________________Reg No: ____________
Part I — Multiple Choice Questions 15 × 1 = 15
Choose the correct answer. (Answer all questions.)
1.Which of the following is a crustacean? a. Prawn b. Snail c. Sea anemone d. Hydra[1]
2.When a cockroach tries to enter into the ear of a sleeping person, which one of the following process will start? a) Unconditioned reflex b) Neuro muscular fatigue c) Stimulation of negative feedback mechanism d) conditioned reflex[1]
3.What is the amount of CO 2 released from lungs in a day? a) 20l b) 19l c) 18l d) 119l[1]
4.In which segments the spermatheca are situated a. 6-7 segments, 7-8 segments 8-9 segments b. 6-7 segments, 8-9 segments 9-10 segments c. 8-9 segments, 9-10 segments 10-11 segments d. 7-8 segments, 8-9 segments 9-10 segments[1]
5.Which of the following pairings is correct a) Sensory nerve – afferent b) Motor nerve – afferent c) Sensory nerve – ventral d) Motor nerve – dorsal[1]
6.Where is castle intrinsic factor secreted? a) Intestine b) Digestive passage c) Stomach d) Large intestine[1]
7.The technology of composting and bioremediation of soils and other activities by application of earthworm is called? …………………(a) Vermitech(b) Vermicast(c) Vermicompost(d) Vermiculture[1]
8.Find out the wrong pair of cockroaches. a. Spiracles – Stigmata b. Ostia – Colourless coelomic fluid c. Ostia – Digestive system cockroach d. Supra oesophageal ganglion – Brain[1]
9.The name of the joint present between the atlas and axis is a) synovial joint b) pivot joint c) saddle joint d) hinge joint[1]
10.Name the white blood cells present in lymph? a. Lymphocytes b. Monocytes c. Neutrophils d. Basophils[1]
11.The pigment present in the muscle fiber to store oxygen is a) myoglobin b) troponin c) myosin d) actin[1]
12.Which is the correct sequence? a) Gullet → Glottis → Epiglottis b) Epiglottis → Glottis → Gullet c) Glottis → Gullet → Epiglottis d) Gullet → Epiglottis → Glottis[1]
13.Which of the following option shows the correct matching of disorders and causes. A) Addison’s disease -(i) Hypo secretion of thyroid B) Cushing’s syndrome – (ii) Hypersecretion of parathyroid hormone C) Softening of bone – (iii) Hypo secretion of glucocorticoids D) Gull’s disease (in adults) – (iv) Excess secretion of cortisol Codes: a) A – (ii); B – (i); C – (iii); D – (iv) b) A – (iii); B – (iv); C – (ii); D – (i) c) A – (iii); B – (ii); C – (i); D – (iv) d) A – (iv); B – (iii); C – (iv); D – (ii)[1]
14.The cluster of nerve tissue in the cell body of neurons are called as a) Gyri b) Sulci c) Vermis d) Nerve ganglion.[1]
15.A person is having problems with calcium and phosphorous metabolism in his body. Which one of the following glands may not be functioning. a) Parathyroid c) Pancreas b) Parotid d) Thyroid[1]
Part II — Short Answer Questions 14 × 2 = 28
Answer briefly. (Answer all questions.)
16.Name any two trees on which lac insect grows?[2]
17.What is meant by corpus callosum?[2]
18.What is a blind spot?[2]
19.What is hematocrit?[2]
20.Give notes on synovial joints.[2]
21.What is meant by vermicompost?[2]
22.Based on the water resources where are aquatic organisms cultured? Give examples.[2]
23.What are the three types of aquaculture on the basis of the source?[2]
24.What are the regions of nervous system?[2]
25.What is a brain stem? What are its parts?[2]
26.Why there is a short life span for hormone-like insulin?[2]
27.Why men are finding difficult to urinate in their old age?[2]
28.What is Gastric rugae?[2]
29.What are poultry diseases?[2]
Part III — Long Answer Questions 10 × 5 = 50
Answer in detail. (Answer all questions.)
30.What are the rules to be followed in the nomenclature of organisms?[5]
31.Write an essay on respiratory disorders.[5]
32.Give an account of the peripheral nervous system.[5]
33.What is the function of the antidiuretic hormone? Where is it produced and What stimuli increases or decreases its secretion?[5]
34.What is indigestion?[5]
35.Describe the structure of trachea with a diagram.[5]
36.a) What is micturition? b) How is central nervous system regulates urination?[5]
37.a) Name the cell that secretes the enzyme renin. b) Where is granular cell present? c) What is the role of renin in Osmoregulation.[5]
38.What might be the effect on a person whose diet has less iron content?[5]
39.Nephrons are the functional and structural unit of kidney’s. What is the relationship between glomerulus, Henle’s loop and urine formation?[5]
🔑 Show Answer Key — Set 1
- 1. a. Prawn
- 2. a) Unconditioned reflex
- 3. c) 18l
- 4. a. 6-7 segments, 7-8 segments 8-9 segments
- 5. a) Sensory nerve – afferent
- 6. c) Stomach
- 7. (a) Vermitech
- 8. c. Ostia – Digestive system cockroach
- 9. b) pivot joint
- 10. a. Lymphocytes
- 11. a) myoglobin
- 12. a) Gullet → Glottis → Epiglottis
- 13. The correct answer is b) A – (iii); B – (iv); C – (ii); D – (i). Addison's disease is caused by hyposecretion of glucocorticoids (primarily cortisol) from the adrenal cortex, resulting in weakness, hypotension, and hyperpigmentation. Cushing's syndrome is caused by excess secretion of cortisol from the adrenal cortex, leading to obesity, hypertension, and muscle weakness. Softening of bones, a condition called osteomalacia in adults and rickets in children, is caused by hyposecretion of parathyroid hormone, which leads to inadequate calcium absorption and demineralization of bones. Gull's disease, also known as myxedema, is a condition in adults caused by hyposecretion of thyroid hormones (hypothyroidism), resulting in decreased metabolic rate, weight gain, and mental sluggishness. These correct matchings demonstrate the relationship between hormonal imbalances and their corresponding pathological conditions.
- 14. d) Nerve ganglion.
- 15. a) Parathyroid
- 16. Acacia catechu Acacia nilotica
- 17. The corpus callosum is a large bundle of nerve fibres that connects the left and right cerebral hemispheres of the brain. It is the largest white matter structure in the brain and contains approximately 200 million axons. The corpus callosum enables interhemispheric communication, allowing the two hemispheres to share information and coordinate their activities. This connection is essential for integrated brain function, allowing sensory information processed in one hemisphere to be communicated to the other and enabling coordinated motor responses and unified cognitive processing.
- 18. The blind spot is a region on the retina where the optic nerve and retinal blood vessels enter the eye, located slightly below the posterior pole of the eyeball. This area is devoid of photoreceptors, meaning it contains no rod or cone cells and therefore cannot detect light. As a result, any image that falls on the blind spot cannot be seen. Despite this anatomical gap, we do not perceive a blind spot in our normal vision because the brain fills in the missing information based on the surrounding visual field and the input from the other eye.
- 19. Hematocrit, also known as packed cell volume, is the ratio or percentage of red blood cells to the total volume of blood plasma. It is expressed as a percentage and represents the proportion of blood volume occupied by red blood cells. Hematocrit values are clinically important indicators of oxygen-carrying capacity and overall blood health. Normal hematocrit ranges vary by sex and age, with typical values around 40-45 percent in males and 35-40 percent in females. Abnormally high hematocrit may indicate dehydration or polycythemia, while abnormally low hematocrit may indicate anemia or blood loss.
- 20. Synovial joints are freely movable joints in which the articulating bones are separated by a joint cavity filled with synovial fluid. This fluid acts as a lubricant, reducing friction between the bones and allowing smooth movement. Synovial joints are surrounded by a fibrous capsule and have articular cartilage covering the bone surfaces. Examples include the shoulder, elbow, hip, and knee joints. The presence of synovial fluid and the structure of these joints enable a wide range of movements such as flexion, extension, abduction, and rotation, making them the most mobile type of joint in the human body.
- 21. Vermicompost is a finished product composed primarily of vermicast along with partially decomposed organic matter, plant growth-promoting substances, and other organic materials. It is the end product of the vermiculture process and contains a rich concentration of nutrients, beneficial microorganisms, plant growth promoters, and organic matter essential for plant development. Vermicompost is a complete organic fertilizer that improves soil structure, water retention, and nutrient availability, making it highly valuable for sustainable agriculture and horticulture applications.
- 22. Freshwater culture Brackish water culture, Marine culture, Cultured organism, Fishes, Prawns, Crabs and oysters.
- 23. Aquaculture, the farming of aquatic organisms, can be classified into three main types based on the salinity of the water used. Freshwater aquaculture involves the cultivation of species in environments such as rivers, lakes, ponds, and reservoirs, where the water has a very low salt content. Brackish water aquaculture is practiced in areas where freshwater mixes with saltwater, such as estuaries, deltas, and coastal lagoons, supporting species that can tolerate a range of salinities. Marine water aquaculture, also known as mariculture, takes place in the open sea or coastal marine environments with high salinity, cultivating organisms adapted to saltwater conditions.
- 24. The nervous system in many complex animals, including humans, is broadly divided into three main regions based on their anatomical location and functional roles. These are the Central Nervous System (CNS), the Peripheral Nervous System (PNS), and the Autonomous Nervous System (ANS). The Central Nervous System comprises the brain and spinal cord, serving as the primary control center for processing information and coordinating responses. The Peripheral Nervous System consists of all the nerves that extend outside the CNS, connecting it to the rest of the body, including muscles, organs, and sensory receptors. The Autonomous Nervous System is a specialized part of the PNS that regulates involuntary bodily functions such as heart rate, digestion, respiration, and glandular secretions, operating largely without conscious control.
- 25. The brain stem is the part of the brain that lies between the spinal cord and the diencephalon, forming the lower and posterior portion of the brain. It serves as a vital connection between the brain and spinal cord and contains important centers for regulating basic life functions. The brain stem consists of three main parts: the midbrain, which is located superiorly and contains the cerebral peduncles; the pons, which lies in the middle and serves as a bridge between different brain regions; and the medulla oblongata, which is located inferiorly and controls vital functions such as respiration, heart rate, and blood pressure.
- 26. Insulin has a short lifespan in the bloodstream because it is a peptide hormone that works through a second messenger system involving cyclic AMP (cAMP). Peptide hormones like insulin cannot directly enter cells due to their hydrophilic nature and must bind to cell surface receptors. This binding activates intracellular signaling cascades through second messengers, which produce rapid but temporary effects. Additionally, peptide hormones are susceptible to enzymatic degradation by proteases in the blood and tissues, which quickly breaks them down and terminates their action. This short duration of action allows for precise and rapid control of blood glucose levels in response to changing metabolic demands.
- 27. In old age, men often experience difficulty in urination because the prostate gland, which surrounds the urethra, tends to enlarge with advancing age in a condition called benign prostatic hyperplasia (BPH). As the prostate enlarges, it compresses and narrows the urethra, restricting the normal flow of urine from the bladder. This results in symptoms such as weak urine stream, difficulty initiating urination, incomplete emptying of the bladder, and increased frequency of urination, particularly at night. The enlarged prostate may also obstruct the flow of urine, leading to urinary retention and potential complications if left untreated.
- 28. Gastric rugae are deep folds or wrinkles present in the inner wall of the stomach. These folds are formed by the mucosa and submucosa layers of the stomach wall. When the stomach is empty, these rugae are prominent and give the stomach wall a wrinkled appearance. As food enters the stomach, these folds gradually unfold and flatten to accommodate large meals, allowing the stomach to expand and increase its capacity. This elastic property of gastric rugae enables the stomach to hold and process varying amounts of food efficiently.
- 29. Poultry diseases are infectious and non-infectious conditions that affect domesticated birds raised for meat and egg production. Common poultry diseases include Ranikhet disease, also known as Newcastle disease, which is a highly contagious viral infection that causes severe respiratory and neurological symptoms in affected birds. Coccidiosis is a parasitic disease caused by Coccidia protozoa that primarily affects the intestinal tract of poultry, leading to diarrhea, reduced feed efficiency, and poor growth. Fowl pox is a viral disease that causes characteristic lesions and scabs on the skin and mucous membranes of infected birds. These diseases can cause significant economic losses in poultry farming through reduced productivity, increased mortality rates, and treatment costs, making disease prevention and management crucial for successful poultry production.
- 30. The scientific name should be italicized in printed form and the generic name and specific name should be underlined separately if it is handwritten. * The first alphabet of the generic name should be of uppercase. * The specific name (species) should be in lower case letters. * The name or abbreviated name of the scientist who first published the scientific name may be written after the specific (species) name along with the year of publication, e.g. Felis Leo Linn., 1958. * If the specific (species) name is framed after any person’s name, the name of the species shall end with i, ii or ae. e.g. Ground – dwelling lizard Cyrtodactylus varadgiri.
- 31. The respiratory system is affected by environmental occupational personal and social factors. Following are some of the respiratory disorders: Asthma: It is characterized by narrowing and inflammation of bronchi and bronchioles and difficulty in breathing. Causes: Allergens like dust drugs pollen grains, certain food items like fish. Emphysema: It is chronic breathlessness. It is caused by gradual breakdown of the thin wall of the alveoli decreasing the total surface area of a gaseous exchange. Causes: The widening of the alveoli is called Emphysema. Cigarette smoking reduces the respiratory surface of the alveolar walls. Bronchitis: It is the inflammation of the bronchi. Causes: Pollution smoke ciagratte smoking. Symptoms: Cough shortness of breath sputum in the lungs. Pneumonia: It is the inflammation of the lungs. Causes: Bacteria and virus Symptoms * Sputum production Nasal congestion, Shortness of breath sore throat. * Tuberculosis Causes * Tuberculosis is caused by mycobacterium tubercular. * Infection mainly occurs in the lungs and bones. Symptoms Collection of fluid between the lungs and the chest wall is the main complication of this
- 32. All nervous tissue outside the central nervous system is the peripheral neural system. It includes nerves ganglia enteric plexuses and sensory receptors. Ganglia are Sinai masses of nervous tissue. The neurons of these plexuses help in regulating the digestive system. The specialised structure that helps to respond to changes in the environment are called sensory receptor. This triggers nerve impulses along the afferent fibres to CNS. PNS comprises 12 pairs of cranial nerves and 31 pairs of the spinal nerve. The neural retina layer consists of cones and rods. The yellow flat spot at the centre of the posterior region of the retina is called macula lutea. A small depression present in the centre of the
- 33. ADH which is also called vasopressin or Antidiuretic hormone is secreted from the neurohypophysis. Fluid loss or if blood pressure increases the osmoreceptors of the hypothalamus is stimulated and hence neurohypophysis is stimulated and secretes ADH. When the fluid level and pressure are maintained due to the negative feedback mechanism ADH secretion stops.
- 34. It is a digestive disorder in which the food is not properly digested leading to a feeling of fullness of the stomach. It may be due to in adequate enzyme secretion anxiety food poisoning overeating and spicy food.
- 35. The trachea is semiflexible tube supported by cartilaginous rings. It starts from the pharynx and ends in the lungs there it divides into right and left primary bronchi. With in the lungs the bronchi divided repeatedly into secondary and tertiary bronchi. That further divides into terminal bronchioles and respiratory bronchioles. Bronchi have ‘c’ shaped curved cartilage plates. This plate helps in preventing collapsing as the air pressure changes during breathing. There is no cartilaginous stingray the brarichioles, The rigidity of the bronchioles prevents them from collapsing.
- 36. Micturition is the process of release or expulsion of urine from the urinary bladder to the outside of the body. It is also called urination. The urine formed by the nephrons is transported through the collecting ducts and ureters to the urinary bladder where it is stored until the bladder receives appropriate signals from the central nervous system to expel the urine. The regulation of urination by the central nervous system involves a reflex arc mechanism. When the urinary bladder becomes filled with urine, the stretch receptors present in the bladder wall are stimulated by the distension of the bladder. These stretch receptors send sensory signals to the sacral spinal cord through sensory neurons. The sensory information is processed in the spinal cord, and motor signals are sent back to the bladder through parasympathetic neurons. At the same time, the internal sphincter, which is made of smooth muscle, opens involuntarily in response to these signals. The external sphincter, which is made of skeletal muscle and is under voluntary control, relaxes when the individual consciously decides to urinate. Once both sphincters open, the detrusor muscle of the bladder contracts, and the urine is expelled out through the urethra. In infants, micturition is purely a reflex action, but in adults, it can be voluntarily controlled through higher brain centers.
- 37. a) Renin is secreted by granular cells. b) Granular cells are present in the afferent arteriole. c) The role of renin * A fall in glomerular blood flow blood pressure and filtration rate can activate granular cells of juxtaglomerular cells to release renin. * Renin converts the plasma protein angiotensinogen into angiotensis I and angiotensin II. * Angiotensis II stimulates Na + reabsorption in the proximal convoluted tubule by vasoconstriction of the blood vessels and increases the glomerular blood pressure. * Angiotensis II stimulates adrenal cortex to secrete aldosterone that causes reabsorption of Na +,K + excretion and absorption of water. * This increases the glomerular blood pressure and glomerular filtration rate. * Hence renin regulates osmoregulation.
- 38. The number of red blood cells decreases. Due to the depletion of haemoglobin he finds it difficult to breath. Due to the deficiency of iron anaemia may develop. Due to the deficiency of iron, the oxygen-carrying capacity of haemoglobin reduces.
- 39. Reptiles have reduced glomerulus or lack glomerulus and Henle’s loop and produce hypotonic urine (dilute) Mammalian kidneys produce concentrated urine due to the presence of long Henle’s loop. Aglomerular kidneys of marine fishes produce little urine that is iso osmotic to the body fluid. Amphibians and fresh water fishlack Henle’s loop hence produce dilute urine.
Brain Grain · braingrain.in
Zoology — Practice Paper · Set 2
Class: 11Samacheer KalviMax Marks: 93
Name: ____________________Reg No: ____________
Part I — Multiple Choice Questions 15 × 1 = 15
Choose the correct answer. (Answer all questions.)
1.The marine oysters are composed of a) Calcium carbonate b) Sodium carbonate c) Potassium carbonate d) Magnesium carbonate[1]
2.Which colour is perceived through chloropsin is sensitive to the medium wavelength of 530 mm a) Red cones b) Green cones c) Blue cones d) Red cells.[1]
3.The muscles of urinary bladder is called by this name? a) sphincter muscle b) Detrusor muscle c) constricting muscle d) Peristaltic muscle[1]
4.The urinary bladder is made up this muscle ………………………. a) Detrusor muscle b) Striated muscle c) Sphincter muscle d) None of the above[1]
5.Which of the following is the last phase of the process of digestion?(a) ingestion(b) assimilation(c) eqestion(d) digestion[1]
6.Find out the incorrect pair. a) Starch – Amylase b) Protein – Pepsin c) Casein – Trypsin d) Lipid – Lipase[1]
7.………………. is the part of the fore-brain. a) Cerebrum – Mesencephalon b) Cerebrum – Prosencephalon c) Cerebrum – Diencephalon d) Cerebrum – Parietal lobe.[1]
8.Buccopharyngeal respiration in frog a. is increased when nostrils are closed b. Stops when there is pulmonary respiration c. is increased when it is catching fly d. stops when mouth is opened.[1]
9.Find the correct match. 1. John ray -a. Five kingdom concept 2. Linnaeus -b. Cladogram 3. Ernest Haeckel -c. Binomial nomenclature 4. R.H. Whittaker – d. Methodus Plantarum a. 1 -d,2-c,3-b,4-a b. 1-a,2-b,3-c,4-d c. 1 – c, 2 – a, 3 – b, 4 – d d. 1 – d, 2 – c, 3 – a, 4 – b[1]
10.Find the excretory structure of prawn? a) Malpighian tubules b) Green glands c) Rennette cells d) Peyer gland[1]
11.A person is unable to sleep normally. He may not get proper secretion of?(a) Thyroxine(b) Vasopressin(c) Melatonin(d) Oxytocin[1]
12.Muscles are derived from a) ectoderm b) mesoderm c) endoderm d) neuroectoderm[1]
13.The Tidal Volume of a normal person is a) 800 mL b) 1000-1200 mL c) 500 mL d) 1100-1200 mL[1]
14.Which of the following is not the function of the liver? a. Production of insulin b. Detoxification c. Storage of glycogen d. Production of bile[1]
15.Which of the following best describes the process of gas exchange in the lungs? a) Air moves in and out of the alveoli during breathing. b) Carbon dioxide diffuses from deoxygenated blood in capillaries into the alveolar air c) Oxygen and carbon dioxide diffuse down their concentration gradients between blood and alveolar air d) Oxygen diffuses from alveolar air into deoxygenated blood.[1]
Part II — Short Answer Questions 14 × 2 = 28
Answer briefly. (Answer all questions.)
16.Define Thecodont?[2]
17.What is meant by myofibrils?[2]
18.Sarojini’s father has congestion of the lungs. His doctor advised him to take bed rest and prescribed him an inhaler. What disease is he suffering from? List the symptoms of the disease.[2]
19.Match and find the correct pair. 1)Patella – a) 14 2) Tarsus – b) 5 3) Metatarsus – c) 7 bones 4) Phalanges – d) kneecap[2]
20.Name the first two bones of the vertebral column.[2]
21.What is sporadic goiter?[2]
22.What is flagellar movement?[2]
23.Why do we need a digestive system?[2]
24.What are Osmo confirmers?[2]
25.What are involuntary muscles?[2]
26.Where are pearl oysters seen? a) Kanyakumari coastal region a Bay of Kutch b) Rameshwaram coastal area and Bay of Mannar c) Nagapatinum coastal area and Thoothukudi d) Visahapatinum coastal area and Chennai[2]
27.Choose the wrong statement among the following: a. In earthworm, a pair of male genital pore is present. b. Setae help in the locomotion of earthworms. c. Muscular layer in the body wall of an earthworm is made up of circular muscles and longitudinal muscles d. Typhlosole is part of the intestine of earthworms.[2]
28.What are the nitrogenous waste formed due to the degeneration of amino acid?[2]
29.Why thymus is considered as a lymphoid organ?[2]
Part III — Long Answer Questions 10 × 5 = 50
Answer in detail. (Answer all questions.)
30.What is a wormery or worm bin?[5]
31.Describe white blood cells.[5]
32.a) Name the hormones secreted by the neuro hypophysis? b) Give a brief account of its functions?[5]
33.How can we estimate the efficiency of kidney?[5]
34.Describe structure of a neuron.[5]
35.Explain the structure of the forebrain?[5]
36.What is typical about Addison’s disease.[5]
37.Give the economic importance of silkworm?[5]
38.Select the correct biological term. Lymphocytes, red cells, leukocytes, plasma, erythrocytes, white cells, hemoglobin, phagocyte, platelets, blood clot.[5]
39.Cockroach can live without ahead? How?[5]
🔑 Show Answer Key — Set 2
- 1. a) Calcium carbonate
- 2. b) Green cones
- 3. b) Detrusor muscle
- 4. a) Detrusor muscle
- 5. (c) eqestion
- 6. c) Casein – Trypsin
- 7. c) Cerebrum – Diencephalon
- 8. b. Stops when there is pulmonary respiration
- 9. a. 1 -d,2-c,3-b,4-a
- 10. b) Green glands
- 11. (c) Melatonin
- 12. b) mesoderm
- 13. c) 500 mL
- 14. a. production of insulin
- 15. c) Oxygen and carbon dioxide diffuse down their concentration gradients between blood and alveolar air. This statement best describes gas exchange in the lungs because it encompasses the complete process of gas exchange. Oxygen diffuses from the alveolar air where its concentration is high into the deoxygenated blood in the pulmonary capillaries where its concentration is low. Simultaneously, carbon dioxide diffuses from the deoxygenated blood where its concentration is high into the alveolar air where its concentration is low. Both gases move down their respective concentration gradients, which is the fundamental principle driving gas exchange. While option d is partially correct in describing oxygen diffusion, option c provides the more comprehensive and accurate description of the bidirectional gas exchange process that occurs in the lungs.
- 16. Thecodont dentition refers to a specific type of tooth attachment in which each tooth is firmly embedded in a socket or alveolus in the jaw bone. The term thecodont is derived from the Greek words 'theca' meaning sheath or socket and 'odont' meaning tooth. In this type of dentition, the root of each tooth fits snugly into a bony socket in the maxilla or mandible, and the tooth is held in place by a specialized connective tissue called the periodontal ligament. This arrangement provides a strong and stable attachment that allows the teeth to withstand the considerable forces generated during mastication. Thecodont dentition is characteristic of mammals, including humans, and represents an evolutionary advancement over other types of tooth attachment such as acrodont, in which teeth are attached to the surface of the jaw bone, or pleurodont, in which teeth are attached to the inner surface of the jaw bone. The thecodont type of attachment allows for efficient feeding and is considered an important adaptation in mammals.
- 17. Myofibrils are the fundamental contractile units within muscle cells. Each muscle, whether skeletal, cardiac, or smooth, is composed of numerous long, cylindrical muscle fibers. Within these muscle fibers, there are many smaller, parallelly arranged structures known as myofibrils. Myofibrils themselves are made up of repeating units called sarcomeres, which contain the contractile proteins actin and myosin. The interaction between these proteins within the myofibrils is responsible for muscle contraction and relaxation, enabling movement and various bodily functions.
- 18. Sarojini's father is suffering from pneumonia, a respiratory infection that causes inflammation of the lungs. The symptoms of pneumonia include sputum production, which is the coughing up of mucus or phlegm from the respiratory tract, nasal congestion that blocks the nasal passages, shortness of breath or difficulty in breathing due to reduced oxygen exchange in the lungs, and sore throat caused by inflammation of the throat tissues. Additional common symptoms may include fever, chest pain, fatigue, and chills. Bed rest helps the body conserve energy for fighting the infection, while an inhaler delivers medication directly to the lungs to help open airways and reduce inflammation, making breathing easier and promoting recovery.
- 19. The correct pair is 4) Phalanges – d) kneecap. Let's break down the matching: 1) Patella is the kneecap, which is a sesamoid bone. 2) Tarsus refers to the bones of the ankle, which are 7 in number. 3) Metatarsus refers to the bones of the sole of the foot, which are 5 in number. 4) Phalanges are the bones of the fingers and toes, and there are 14 in each hand and foot.
- 20. Atlas Axis
- 21. It is a genetic disease It is not caused by iodine or thyroxine deficiency.
- 22. Flagellar movement is the type of locomotion that occurs due to the lashing or whipping action of flagella, which are long, thread-like structures extending from the cell body. Flagella move in a wave-like pattern, propelling the cell forward through a liquid medium. This type of movement is commonly observed in sperm cells, which use their single flagellum to swim through the female reproductive tract toward the ovum. Bacteria also possess flagella that enable them to move through their environment. The flagellar movement is essential for the motility and reproductive success of these cells.
- 23. We need a digestive system because the food we consume consists of macromolecules such as complex carbohydrates, proteins, and lipids that are too large to be absorbed directly by the intestinal epithelium. These macromolecules are insoluble and inabsorbable in their original form. The digestive system breaks down these large, complex food molecules into smaller, simpler micro-molecules through both mechanical and chemical processes. Mechanical digestion involves physical breakdown through chewing and churning, while chemical digestion involves enzymatic breakdown using various digestive enzymes. Once broken down into smaller units such as monosaccharides, amino acids, fatty acids, and glycerol, these nutrients become soluble and absorbable. The digestive system thus transforms indigestible macromolecules into absorbable forms that can be transported across the intestinal wall into the bloodstream and distributed to cells throughout the body for utilization in energy production, growth, and maintenance.
- 24. Osmoconformers are organisms that are unable to maintain a constant internal osmotic concentration and instead allow their body fluids to change in osmotic concentration in accordance with changes in the external environment. These organisms do not actively regulate their internal osmotic pressure and their blood osmolarity fluctuates with the osmolarity of their surroundings. Examples include most marine invertebrates such as molluscs, echinoderms, and sharks. These organisms are typically found in stable osmotic environments like the ocean where the salinity remains relatively constant, allowing them to survive without expending energy on osmoregulation.
- 25. Involuntary muscles are those whose functions cannot be directly or consciously controlled by an individual. These muscles operate autonomously, regulated by the autonomic nervous system, ensuring the smooth functioning of internal organs without requiring conscious thought. Smooth muscles are a prime example of involuntary muscles, found in the walls of internal organs such as blood vessels, the stomach, and the intestines. Their contractions are responsible for processes like blood pressure regulation, digestion, and movement of substances through tubular structures, all occurring without direct volitional control.
- 26. Pearl oysters, the source of natural pearls, are found in specific coastal regions known for their suitable environmental conditions. In India, significant populations of pearl oysters are observed along the southern coast. Notably, the coastal areas around Kanyakumari, situated at the southern tip of the Indian peninsula, are known for pearl oyster beds. Additionally, the Bay of Kutch, located in the western part of India, also supports pearl oyster fisheries.
- 27. d. Typhlosole is part of the intestine of earthworm. This statement is incorrect. While the typhlosole is indeed a part of the intestine in earthworms, the question asks to choose the wrong statement among the given options. The typhlosole is a prominent, internal fold of the dorsal wall of the intestine, running along most of its length. Its primary function is to increase the surface area for absorption of digested food, thus making it a crucial component of the earthworm's digestive system. Therefore, stating it is part of the intestine is correct, making this option the incorrect choice if the intent was to identify a wrong biological fact about the earthworm.
- 28. Ammonia Urea Uric acid
- 29. The thymus is considered a lymphoid organ because it serves as a primary site for the development and maturation of lymphocytes, particularly T lymphocytes. Lymphocytes that originate from the bone marrow migrate to the thymus where they undergo education and differentiation to become immunocompetent T lymphocytes capable of recognizing and responding to foreign antigens. The thymus produces thymosin and other hormones that facilitate this maturation process. These educated T lymphocytes then leave the thymus and provide cell-mediated immunity throughout the body by directly attacking infected or abnormal cells. Therefore, the thymus is classified as a lymphoid organ due to its essential role in immune cell development and the production of immune factors.
- 30. A wormery, also known as a worm bin, is a specially designed container system used for the recycling and composting of organic waste materials using earthworms. In a wormery, earthworms are introduced to decompose waste food, leaf litter, and other biomass materials. The earthworms break down these organic materials through their digestive processes, converting them into nutrient-rich compost. This compost produced in a wormery is of superior quality compared to regular compost because it is enriched with earthworm castings, which are highly beneficial for soil fertility and plant growth. Wormeries are an excellent sustainable method for managing household and garden waste while simultaneously producing a valuable fertilizer. They are compact, odor-free when properly maintained, and can be kept indoors or outdoors, making them suitable for both urban and rural settings.
- 31. White blood cells are colourless amoeboid nucleated cells devoid of hemoglobin and hence colourless. * 6000 – 8000 per cubic mm of WBC s are seen in the blood. WBCs are synthesized in the bone marrow these are of two types. * Granulocytes and agranolocytes. I Granulocytes: a) Neutrophils: * They are also called heterophils. Hence the nucleus has 3-4 lobes they are called polymorphonuclear. * This constitutes about 60 – 65 % of the total WBC. b) Eosinophils: * They have a bilobed nucleus. Eosinophils Basophils Neutrophils * It constitutes about 2 – 3 % of total WBCs. * Their number increases during allergic reactions. c) Basophils: * They are less numerous than any other type of WBCs constituting 0.5 % -1 % of total WBCs. * The nucleus is large and has granules in the cytoplasm. * They secrete heparin serotonin and histamines. II A granulocytes: a) Lymphocytes: * They are secreted in the lymph gland and spleen. * Lymphocytes constitute 28% of WBCs. They have large nucleus and small amount of cytoplasm. * The two types of lymphocytes are B and T cells. * B cells produce antibodies to neutralize the harmful effects of foreign substances. T cells are involved in cell-mediated immunity. b) Monocytes: * They are phagocytic cells. They have kidney-shaped nucleus. They constitute 1 – 3 % of the total WBCs. * The macrophages of the central nervous system are the microglia and in the liver they are called “Kupffer cells” and in the pulmonary region they are the alveolar macrophages.
- 32. a. Neuro hypophysis secretes two hormones. * Vasopressin or anti-diuretic hormone * Oxytocin. Vasopressin or Anti diuretic Hormone (ADH):- * It is a peptide hormone. * it promotes reabsorption of water and electrolytes by distal tubules of the nephron and thereby reduces the loss of water through urine. * Hence it is called an anti-diuretic hormone. * When released in large amounts it causes constriction of blood vessels and increases blood pressure. * ADH deficiency causes Diabetes insipidus which induces the production of a large amount of urine. Oxytocin:- * It means quick birth. * It is a peptide hormone. 3. It stimulates vigorous contraction of the smooth muscles of the uterus during childbirth. 4. And it also stimulates the ejection of milk from the mammary glands. b. Chemical nature: * The insulin hormone is a peptide hormone with 51 amino acids. * The molecular weight of insulin hormone is 5734 Dalton. * It consists of two chains A and B which are linked together by disulphide bridges formed between cystine residues. Role of Insulin: * It increases uptake of glucose into body cells especially muscle and fat cells. * It inhibits the breakdown of glycogen to glucose, the conversion of amino acids or fats to glucose. Thus it decreases the blood glucose level and so insulin is rightly called as a hypoglycemic hormone. c. How can this condition be reversed? * maintenance of normal body weight through adoption of nutritional habits ie. balanced diet and physical exercise. * Correction of over nutrition and obesity may reduce the risk of diabetes and its complications. * Alcohol and smoking should be avoided. * Control of high blood pressure elevated cholesterol and high triglyceride levels.
- 33. The efficiency of the kidney can be estimated by calculating the renal clearance, which is the volume of blood completely cleared of a particular substance per unit time. If the renal clearance of a substance is equal to the glomerular filtration rate, it indicates that the substance is filtered at the glomerulus but not reabsorbed or secreted in the renal tubules, suggesting efficient filtration with little or no reabsorption and secretion. If the renal clearance is less than the glomerular filtration rate, it indicates that some of the filtered substance has been reabsorbed in the tubules. If the renal clearance is greater than the glomerular filtration rate, it indicates that the substance has been secreted into the tubules in addition to being filtered. By comparing the renal clearance values of different substances, we can assess the kidney's ability to selectively filter, reabsorb, and secrete various substances, thereby evaluating its overall efficiency in maintaining the composition of blood and producing urine.
- 34. Neuron is composed of three region. * Cell body * Dendrites * axon. Cell body: The cell body is spherical. There is no centriole. The plasma membrane covering the neuron is called neurilemma and axon is axolemma. Dendrites: The repeatedly branched short fibres coming out of the cell bod dendrites which transmit impulses towards the cell body in it’s cytoplasm Nissl’s granules are present. Axon: It is a long fibre that arises from a cone shaped area of the cell body. There is no golgi bodies and Nissis granules in its cytoplasm. The axon of peripheral nerves is surrounded by Schwann’s cells to form myelin sheath. The myelin sheath is not continuous. There are gaps in the myelin sheath between an adjacent Schwann cells called nodes of Ranvier. Each branch at the distal end of the axon terminates into a knob like structure called synaptic knob which possesses synaptic vesicles filled with transmitters. The axon transmits nerve impulses away from the body to neuro muscular junction. The myelinated nerve cell transmits impulses faster than non – myelinated nerve cells.
- 35. The forebrain comprises the following regions: Cerebrum and Diencephalon. The cerebrum is the ‘seat of intelligence’ and forms the major part of the brain. The cerebrum consists of an outer cortex, inner medulla and basal nuclei. The superficial region of the cerebrum is called the cerebral cortex, which looks grey due to the presence of unmyelinated nerve cells. Cerebral cortex – consists of the neuronal cell body, dendrites, associated glial and blood vessels. The surface of the cerebrum shows many convolutions (folds) and grooves. The folds are called gyri, the shallow grooves between the gyri are called sulci and deep grooves are called fissures. These sulci and gyri increase the surface area of the cerebral cortex. Several sulci divide the cerebrum into eight lobes; a pair of frontals, parietals, temporals and occipital lobes. A median longitudinal fissure divides the cerebrum longitudinally into two cerebral hemispheres. A transverse fissure separates the cerebral hemispheres from the cerebellum. The hemispheres are connected by a tract of nerve fibres called corpus callosum. Cerebral cortex has three functional areas namely sensory areas occur in the parietal, temporal and occipital lobes of the cortex. They receive and interpret the sensory impulses. Motor area of the cortex which controls voluntary muscular movements lies in the posterior part of the frontal lobes. The areas other than sensory and motor areas are called Association areas that deal with integrative functions such as memory, communications, learning and reasoning. Inner to the cortex is medulla which is white in colour and acts as a nerve tract between the cortex and the diencephalon. Diencephalon consists largely of following three paired structures. The epithalamus forms the roof of the diencephalon and it is a non-nervous tissue. The anterior part of the epithalamus is vascular and folded to form the choroid plexus. Just behind the choroid plexus, the epithalamus forms a short stalk that ends in a rounded body called pineal body which secretes the hormone, melatonin which regulates the sleep and wake cycle. Thalamus is composed of grey matter which serves as a relay centre for impulses between the spinal cord, brain stem and cerebrum. Within the thalamus, information is sorted and edited and plays a key role in learning and memory. It is a major coordinating centre for sensory and motor signaling. Hypothalamus forms the floor of the diencephalon. The downward extension of the hypothalamus, the infundibulum connects the hypothalamus with the pituitary gland. The hypothalamus contains a pair of small rounded body called mammillary bodies that are involved in olfactory reflexes and emotional responses to odour. Hypothalamus maintains homeostasis and has many centres which control the body temperature, urge for eating and drinking. It also contains a group of neurosecretory cells which secrete the hypothalamic hormones. Hypothalamus also acts as the satiety centre. Limbic system: The inner part of the cerebral hemisphere constitutes the limbic system. The main components of limbic system are olfactory bulbs, cingulate gyrus, mammillary body, amygdala, hippocampus and hypothalamus. The limbic system is called the ‘emotional brain’ because it plays a primary role in the regulation of pleasure, pain, anger, fear, sexual feeling and affection. The hippocampus and amygdala also play a role in memory. Brain stem is the part of the brain between the spinal cord and the diencephalon. It consists of mid-brain, pons varolii and medulla oblongata.
- 36. There is a hyper pigmentation of the skin. It is caused due to hypo secretion of glucocorticoids from the adrenal cortex. Muscular weakness low BP, loss of appetite vomiting, low metabolic rate subnormal temperature reduced blood volume and weight are the other symptoms of Addison’s disease.
- 37. The rearing of silkworm on a commercial scale is called sericulture. It is an agro-based industry comprising of Cultivation of food plants for the silkworms. Rearing of silkworms. Reeling and spinning of silk. Silk fibers are utilized in preparing silk clothes. Silk is used in industries and for military purposes. Silk is used in the manufacture of fishing fibres, parachutes, cartridge bags, insulation coils for telephone, wireless receivers, tyres of racing cars, filter fibres, in medical dressings and suture materials.
- 38. a. Disc-shaped cells which are concave on both sides. Red cells b. Most of these have a large bilobed nucleus Leucocytes c. Enable red cells to transport blood. Haemoglobin d. The liquid part of the blood Plasma e. Most of them move and change shape like an amoeba Leucocytes f. Consists of water and important dissolved substances. Plasma g. Destroyed in the liver and spleen after circulating in the blood for four months. Red cells h. The substances which give red cells their colour Haemoglobin i. Another name for red cells Erythrocytes j. Blood that has been changing to jelly Blood clot k. A word that means cell eater Phagocytes l. Cells without nucleus Red cells m. White cells made in the lymphatic tissue Lymphocytes n. Blocks wound and prevent excessive bleeding. Blood clot o. Fragment of cells which are made in the bone marrows Platelets p. Another name for white blood cells. Leucocytes q. Slowly releases oxygen to blood cells. Haemoglobin r. Their function is to help blood clots in wounds. Platelets
- 39. A cockroach can survive for approximately one week without its head because respiration in cockroaches is independent of the head. Unlike humans and many other animals, cockroaches do not have nostrils or lungs located in the head region. Instead, their respiratory system is distributed throughout the body. The abdomen contains ten pairs of spiracles that are directly connected to the tracheal system and tracheoles. These spiracles allow oxygen to enter the haemocoel and facilitate gas exchange with the hemolymph and body tissues. Since the spiracles are located on the thorax and abdomen rather than the head, the cockroach can continue to respire even after decapitation. However, the headless cockroach will eventually die due to inability to feed and drink water, not from respiratory failure. This remarkable adaptation demonstrates the efficiency of the insect tracheal respiratory system.
Brain Grain · braingrain.in
Zoology — Practice Paper · Set 3
Class: 11Samacheer KalviMax Marks: 93
Name: ____________________Reg No: ____________
Part I — Multiple Choice Questions 15 × 1 = 15
Choose the correct answer. (Answer all questions.)
1.What is the pressure in the afferent arthery of Glomerulus? a) 55 mm Hg b) 50 mm Hg c) 57 mm Hg d) 58 mm Hg[1]
2.The lower portion of the midbrain consists of a pair of longitudinal nervous bands called a) Emotional brain b) Cerebral peduncles c) Pons d) Vermis[1]
3.Name the lubricating fluid which is secreted from the gland present at the base of the eyelashes. a) Lacrymal gland b) Cerebro-spinal fluid c) Thymus gland d) Sebaceous glands.[1]
4.Confirm A: Red blood cell contains more hemoglobin Reason B: There are no cell organelles in the red blood cells. a. A – True, B – False b. A – True, B – True c. A – False, B – True d. A – False, B – False[1]
5.A gland which is well developed in newborn child and produce lymphocytes a) Thyroid gland b) Thymus c) Parathyroid gland d) Pineal gland[1]
6.What is the length of matured silkworm? a) 7.5 cm b) 7cm c) 8.5 cm d) 8 cm[1]
7.The functional unit of a muscle fibre is a) sarcomere b) sarcoplasm c) myosin d) actin[1]
8.Which of the following is not a feature of frog?(a) presence of webbed deet(b) absence of teeth(c) smooth and moist skin(d) slender body[1]
9.Life span of Bombyxmori a) 2-3 days b) 2 – 4 days c) 2-5 days d) 4 – 7 days[1]
10.How much urine can be stored up in the bladder? a) 300-600 ml b) 200-300 ml c) 400-700 ml d) 500-800 ml[1]
11.Which is the prominent bone of the pelvic bone? a) Ilium b) Ischium c) Pubis d) all the above[1]
12.Name the connective tissue which covers the entire muscle? a) Epimycium b) Perimycium c) Endomyciurn d) Mesornyscium[1]
13.Which of the following is found in the upper layers of the soil?(a) Perionyx exavatus(b) Octochaetona thurstoni(c) Lampito mauritii(d) Eudrilus eugeniae[1]
14.Attacus ricini produces ……………. silk?(a) Muga(b) Tassar(c) Mulberry(d) Eri[1]
15.What type of fibres are found in connective tissue matrix? a. Collagen b. Areolar c. Cartilage d. Tubular[1]
Part II — Short Answer Questions 14 × 2 = 28
Answer briefly. (Answer all questions.)
16.What is post ganglionic neuron?[2]
17.What is the Calorific value of carbohydrates?[2]
18.What are the bones that make the pelvic girdle?[2]
19.What are the organisms farming through aquaculture?[2]
20.Give the systematic classification of cockroaches?[2]
21.Name the hormones that their secretions are regulated by negative feedback mechanisms?[2]
22.What is tectorial membrane?[2]
23.Name the hormones that play a key role in milk secretion?[2]
24.What are the three chambers of cochlea?[2]
25.How are animals classified on the basis of their economic importance?[2]
26.Why are earthworms called ‘friends of farmers’?[2]
27.Find out the correct statement a. In male cockroach, the reproductive sac lie anteriorily. b. In female cockroaches chitinous plates gonapophyses are present around the female genital aperture. c. In male cockroach the sternum of 10th segment have pair of anal cerci. d. In the 12th segment anal styles are seen.[2]
28.What are gastric rugae?[2]
29.What is meant by fish meal?[2]
Part III — Long Answer Questions 10 × 5 = 50
Answer in detail. (Answer all questions.)
30.What are the main duties of a worker bee?[5]
31.Why elephants and other wild animals are entering the human living areas?[5]
32.Give notes on slow oxidative fibres.[5]
33.What is the role of pass intermedia in mammals and in other vertebrates?[5]
34.What are the external factors affecting fish culture?[5]
35.Give an account of the functional components of a reflex arc.[5]
36.What is tubular secretion? Name the substances secreted through the renal tubules?[5]
37.List the primary functions of the respiratory system?[5]
38.Give an account on parathyroid hormones its hypo and hyper secretion deficiencies.[5]
39.The cockroach can survive with out the head. Whether the statement is correct or wrong if it is so give reason?[5]
🔑 Show Answer Key — Set 3
- 1. a) 55 mm Hg
- 2. b) Cerebral peduncles
- 3. d) Sebaceous glands.
- 4. b. A – True, B – True
- 5. b) Thymus
- 6. a) 7.5 cm
- 7. a) sarcomere
- 8. (b) absence of teeth
- 9. a) 2 – 3 days
- 10. a) 300-600 ml
- 11. a) Ilium
- 12. a) Epimycium
- 13. (c) Lampito mauritii
- 14. (d) Eri
- 15. a. Collagen
- 16. A postganglionic neuron is the second neuron in an autonomic reflex arc that originates from an autonomic ganglion. Its cell body is located within the autonomic ganglion, where it receives signals from the preganglionic neuron. The postganglionic neuron extends its axon from the ganglion to the visceral effector organs such as the heart, lungs, digestive organs, and blood vessels. The postganglionic neuron conveys nerve impulses from the autonomic ganglion to these effector organs, resulting in physiological responses that are regulated by the autonomic nervous system.
- 17. The caloric value of Carbohydrates is 4.1 calories/gram. The physiological fuel value is 4 Kcal/gram.
- 18. Ilium Ischium Pubis
- 19. The organisms farmed through aquaculture include fish, mollusks, crustaceans, and aquatic plants. Fish farming is the most common form of aquaculture and includes species such as salmon, tilapia, and carp. Mollusks such as oysters and mussels are also cultivated commercially. Crustaceans including shrimp and prawns are important aquaculture products. Additionally, aquatic plants are grown for food, animal feed, and other commercial purposes, making aquaculture a diverse and economically significant practice.
- 20. Phylum – Arthropoda Class – Insecta Order – Orthoptera Genus – Periplaneta Species – Americana
- 21. Thyroid-stimulating hormone TSH or Thyrotropin Adreno corticotropic hormone or ACTH
- 22. The tectorial membrane is a roof-like structure that overhangs the organ of Corti throughout its entire length in the inner ear. It is a stiff gel membrane composed of proteins and carbohydrates that extends over the sensory hair cells of the organ of Corti. When sound vibrations cause the basilar membrane to move, the hair cells bend and come into contact with the tectorial membrane, which stimulates the hair cells and initiates the process of sound perception. The tectorial membrane plays a crucial role in the mechanical transduction of sound waves into neural signals.
- 23. Prolactin or lactogenic hormone or mammotropin or luteotropic hormone. Oxytocin.
- 24. Scala vestibule Scala tympani Scala media
- 25. Animals for food and food products. Economically beneficial animals. Animals of aesthetic importance. Animals for scientific research.
- 26. Earthworms are called 'friends of farmers' because they play a vital and indispensable role in maintaining and improving soil fertility. Through their burrowing activities, earthworms aerate the soil, creating channels that improve water infiltration and root penetration. As they consume organic matter and soil, they break it down and excrete nutrient-rich castings that enhance soil structure and fertility. Their activities increase the availability of essential nutrients to plants and promote beneficial microbial activity in the soil. This makes earthworms invaluable for sustainable agriculture and soil health maintenance.
- 27. b. In female cockroaches chitinous plates gonapophyses are present around the female genital aperture. This statement is correct. Gonapophyses are specialized chitinous structures that form the ovipositor in female cockroaches, surrounding and protecting the female genital aperture. The other statements are incorrect: in male cockroaches, the reproductive sac lies posteriorly, not anteriorly; in male cockroaches, the sternum of the 9th segment, not the 10th segment, bears a pair of anal cerci; and anal styles are found in the 9th segment, not the 12th segment.
- 28. Gastric rugae are numerous folds or ridges present in the inner mucosal lining of the stomach. These folds are arranged in a longitudinal pattern and give the inner surface of the stomach a wrinkled appearance when the stomach is empty or partially filled. The primary function of gastric rugae is to allow the stomach to expand and accommodate large meals without excessive stretching of the stomach wall. When food enters the stomach, these folds gradually unfold and flatten out, enabling the stomach to increase its volume significantly. This expandable capacity is important for storing food and allowing adequate time for mechanical and chemical digestion to occur. The rugae also increase the surface area of the stomach lining, which facilitates better contact between the gastric juices and food particles, thereby enhancing the efficiency of digestion. As the stomach empties and contracts, the rugae reform, returning the stomach to its original folded state.
- 29. Fish meal is a protein-rich feed ingredient that is prepared from fish waste materials remaining after oil extraction from fish. The process involves collecting fish offal, bones, and other byproducts generated during fish processing, drying them, and grinding them into a fine powder. Fish meal is an excellent source of high-quality protein, essential amino acids, and minerals, making it a valuable nutritional supplement used extensively in animal feed formulations for aquaculture, poultry, and livestock industries.
- 30. Worker bees perform a variety of essential tasks throughout their lifetime, with their duties changing as they age in a process called temporal polyethism. During the first half of her life, lasting approximately three weeks, the worker bee performs indoor duties within the hive. She secretes royal jelly from her hypopharyngeal glands to feed the larvae and the queen, and prepares bee-bread, which is a mixture of pollen and honey, to nourish the developing larvae. She feeds the queen bee and takes care of her needs, maintains the health and cleanliness of the queen, and also feeds and cares for the drones. The worker bee secretes beeswax from special glands on her abdomen and uses this wax to build and repair the hexagonal combs that form the structure of the hive. She continuously cleans the cells of the comb and fans the beehive with her wings to maintain proper temperature and humidity and to evaporate excess moisture from nectar. As she matures, she assumes the role of a soldier bee and guards the entrance of the hive, protecting it from intruders and potential threats. In the second half of her life, lasting approximately three weeks, the worker bee transitions to foraging duties. She searches for and gathers pollen from flowers, which is essential for protein nutrition of the colony. She collects nectar, which is processed into honey as an energy source for the hive. She also gathers propolis, a resinous substance used to seal and sterilize the hive, and collects water for various hive functions. These diverse roles ensure the survival and productivity of the entire bee colony.
- 31. For the construction of houses, dams, and factories forests are destroyed. The area surface of forests is also getting reduced. As the bull elephant is hunted for their tusks the cow elephant during breeding season enters in to the dwelling area of people.
- 32. These fibers have low rates of myosin ATP hydrolysis but have the ability to make large amounts of ATP. This type of fiber seen in long-distance swimmers and long-distance runners.
- 33. In mammals the role of pass intermedia is insignificant. * In other vertebrates it secretes melanocyte stimulating hormone (MSH) * It induces pigmentation in skin. (5 Marks) IV. Brief Answers
- 34. External factors affecting fish culture are environmental and physical conditions that significantly influence the growth, reproduction, and survival of cultured fish. Temperature plays a crucial role as it affects metabolic rates, feeding behavior, and breeding cycles of fish species. Light influences fish behavior, feeding patterns, and reproductive cycles, with photoperiod being particularly important for triggering breeding in many species. Water quality parameters are critical, including pH which affects fish physiology and enzyme function, hardness which influences osmoregulation, and salinity which determines the type of fish that can be cultured in specific water bodies. Dissolved oxygen is essential for respiration and must be maintained at adequate levels to prevent fish mortality. Water current and turbidity also affect fish culture, as currents influence oxygen distribution and feeding efficiency, while turbidity affects light penetration and visibility for feeding. Rainfall and flooding can alter water chemistry, temperature, and oxygen levels, potentially causing stress or mortality in cultured fish populations. These external factors must be carefully monitored and managed to ensure optimal conditions for successful fish culture and production.
- 35. Sensory receptor – It is a sensory structure that responds to specific stimulus. Sensory neuron – This neuron takes the sensory impulse to the grey (afferent) matter of the spinal cord through the dorsal root of the spinal cord. Inter neuron – It may serve to transmit the impulses from the sensory neuron to the motor neuron. Motor neuron – It transmits impulse from CNS to the effector organ Effector neuron – It may be a muscle or gland which responds to the impulse received. * Lacrymal glands located in the upper lateral region of each orbit secrete tears. * Tears are secreted at the rate of 1 ml/day. * Tears contain salt mucus and lysozyme enzyme to destroy bacteria. * The protective mucus membrane present in the outer surface of the eye ball. * The eye has two compartments anterior and posterior compartments filled with aqueous humour and vitreous humour respectively. * The eye ball is consists of three layers sclera, vascular choroid and sensory retina. Sclera: * It consists of anterior cornea and the posterior sclera. * Cornea is composed of stratified squamous epithelium. Sclera forms the white of the eye and protects the eyeball. * At the junction of the sclera and the cornea is a channel called canal of schlemm which continuously drains out the excess of aqueous humour. Choroid layer: It is highly vascularised pigmented layer.
- 36. Tubular secretion is the active transport process by which specific substances are moved from the blood in the peritubular capillaries into the tubular fluid or filtrate within the renal tubules. Unlike glomerular filtration, which is a passive process, tubular secretion is an active process that requires energy in the form of ATP and can move substances against their concentration gradient. The substances secreted through the renal tubules include hydrogen ions (H+), potassium ions (K+), ammonium ions (NH4+), creatinine, and organic acids such as uric acid and certain drugs. These substances are secreted primarily in the proximal convoluted tubule and the distal convoluted tubule. Tubular secretion serves important functions including the regulation of blood pH by secreting excess hydrogen ions, the regulation of potassium levels in the blood, the elimination of metabolic wastes like creatinine and uric acid, and the excretion of foreign substances and drugs. This process ensures that potentially harmful substances are removed from the blood and added to the urine for elimination from the body.
- 37. It helps in the exchange of O 2 and CO 2 between the atmosphere and the blood. It maintains homeostatic regulation of body pH. It protects us from inhaled pathogens and pollutants. It maintains the vocal cords for normal communication. It removes the heat produced during cellular respiration through breathing.
- 38. Four tiny parathyroid glands are found in the posterior wall of the thyroid gland. * It is composed of Chief cells and oxyphil cell. * The chief cells secrete parathyroid hormone and the function of oxyphill cell are not known Functions * It involves in calcium and phosphate. * It promotes the activation of vitamin D to increase calcium absorption by intestine. Hyper secretion * Hyper parathyroidism causes demineral isation of calcium in bones. * Thus increasing the calcium and phosphate level in the blood. * PTH enhances the reabsorption of calcium and excretion of phosphate by the renal tubules. Hypo secretion * Due to the hyposecretion of PTH serum calcium level decreases and the serum phosphate level increases. * Generalised convulsion occurs.
- 39. The statement that a cockroach can survive without its head is correct. A cockroach can live for approximately one week without its head, which is a remarkable adaptation that distinguishes insects from many other animals. The reason for this survival ability lies in the cockroach's open circulatory system, where blood is not confined to vessels but bathes the organs directly in the body cavity. More importantly, cockroaches breathe through a system of spiracles, which are small holes or openings located on each of their body segments. These spiracles allow the cockroach to obtain oxygen directly from the air without depending on the mouth or head for respiration. Therefore, even without a head, the cockroach can continue to breathe through these segmental spiracles and maintain basic metabolic functions for a limited period until other vital processes fail.