Title Ex-1 excretory Products and their (Solution file).docx.pdf ✅

30 EXCRETORY PRODUCTS AND THEIR ELIMINATION EXERCISE – 1: Basic Objective Questions Modes of Excretion, Other Nitrogenous Wastes 1. Protonephridia or flame cells or solenocytes are the excretory structures in (a) Platyhelminthes/flatworms (b) Rotifers and some annelids (c) Cephalochordate (Branchiostoma) (d) All of the above Ans. (d) Sol. The flame cell is a specialized excretory cell found in some freshwater invertebrates, including cephalochordata, platyhelminthes, rotifers and some annelids. Flame cells function in the same way as the kidney, like removing waste material. Bundles of flame cells are called protonephridia. They are meant for excretion and osmoregulation. 2. Antennary glands of crustaceans are meant for (a) Olfaction (b) Excretion (c) Respiration (d) Neurosecretion Ans. (b) Sol. In decapod crustaceans, the excretory organ is known as antennary glands or green glands. They are present at the base of the antennae. These glands are also called maxillary or internal glands. Their function is similar to the kidney in vertebrates. They help in eliminating waste and also work in osmoregulation. 3. Nephridia are the tubular excretory structures in some animals for (a) Removal of nitrogenous waste (b) Maintain fluid and ionic balance (c) Both (a) and (b) (d) Form a part of neural system Ans. (c) Sol. Nephridia are the tubular excretory structures in some animals such as earthworms and annelids, for the purpose of removal of nitrogenous waste and maintenance of fluid and ionic balance (osmoregulation). 4. The production of urea and uric acid instead of ammonia as the nitrogenous waste product for excretion is (a) Aquatic adaptation (b) Terrestrial adaptation (c) Anthorpogenic adaptation (d) All of these Ans. (b) Sol. The production of urea and uric acid instead of ammonia as the nitrogenous waste product for excretion is a terrestrial adaptation. These nitrogenous wastes require less water for excretion than ammonia. Hence, water is conserved which is a necessary adaptation for surviving on land. 5. Which among the following requires least water for its elimination? (a) Urea (b) Ammonia (c) Both urea and ammonia (d) Uric aid Ans. (d) Sol. Among the common nitrogenous wastes, uric acid is least toxic and requires least quantity of water for its elimination. 6. The osmolarity can be maintained by retaining some amount of (a) Ammonia (b) Uric aid (c) Urea (d) All of these Ans. (c) Sol. The osmolarity can be maintained by retaining some amount of urea. The retained urea allows the interstitial fluid to maintain osmolarity to the required level without causing any toxic effect. 7. The method of excretion in most bony fishes is (a) Urea (b) Ammonia (c) Both urea and ammonia (d) Urea, ammonia and uric acid Ans. (b) Sol. Bony fishes are ammonotelic. They excrete ammonia which diffuses out of body surface and gills as ammonium ions. 8. Which one of the following options shows a correct matching pair? (a) Man - Ureotelic (b) Bird - Ammonotelic (c) Fish - Uricotelic (d) Frog - Uricotelic Ans. (a)
31 EXCRETORY PRODUCTS AND THEIR ELIMINATION Sol. Man is ureotelic because they excrete nitrogenous waste in the form of urea. So, (a) is correct but birds are uricotelic, not ammonotelic, fish are not uricotelic they are ammonotelic and frogs are ureotelic, not uricotelic, as their skin is permeable to water. 9. The excretory structure present in most of the insects including cockroach is (a) Malpighian body (b) Green glands (c) Malpighian tubules (d) Nephridia Ans. (c) Sol. The excretory structure present in most of the insects including cockroach is malpighian tubules. Malpighian body or renal corpuscle is the name given to the structure consisting of glomerulus and Bowman’s capsule. 10. Select the correct option representing the excretory organs present in (i) Earthworm, (ii) Centipede, (iii) Prawn, and (iv) Flatworm. (i) (ii) (iii) (iv) (a) Malpighian tubules Flame cell Nephridia Green gland (b) Flame cell Green gland Malpighian tubules Nephridia (c) Nephridia Malpighian tubules Green gland Flame cell (d) Green gland Nephridia Flame cell Malpighian tubules Ans. (c) Sol. In earthworm, nitrogenous wastes are excreted out by nephridia. Malpighian tubules are the part of the excretory system in centipede that runs from the midgut to hindgut and waste products are excreted out through the anus. Prawns have green glands or antennal glands as their excretory organs. These are known as antennal glands because they are present near the base of large antennae and green glands if the excretory pore is green. Flame cells are the excretory cells in flatworms. 11. Urine is always fluid except in (a) Reptiles and amphibians (b) Birds and mammals (c) Birds and reptiles (d) Reptiles and mammals Ans. (c) Sol. Urine is always fluid except in birds and reptiles because birds and reptiles are uricotelic animals; they excrete nitrogenous waste in the form of white paste or powder because uric acid is least soluble in water. 12. Which of the following is the most toxic nitrogenous waste? (a) TMO (b) Urea (c) Uric acid (d) Ammonia Ans. (d) Sol. Ammonia is very toxic to the human brain. People with the impaired liver function will, however, be unable to get rid of their body ammonia fast enough. That may result in excessive concentrations of ammonia in the blood which can cause damage to the brain and body. 13. Which of the following groups contains uricotelic animals only? (a) Reptiles, birds, land snails, insects (b) Reptiles, birds, land snails, aquatic insects (c) Amphibians, birds, land snails, insects (d) Amphibians, reptiles, birds, insects Ans. (a) Sol. Animals that excrete nitrogenous waste in the form of uric acid are known as uricotelic animals. Uric acid is the least poisonous and least soluble in water as compared to ammonia and urea. Examples of uricotelic animals are mostly terrestrial animals and birds. 14. The following substances are the excretory products in animals. Choose the least toxic form among them. (a) Urea (b) Uric acid (c) Ammonia (d) Carbon dioxide Ans. (b) Sol. Uricotelic animals tend to excrete uric acid as a waste in the form of a white paste or powder. Uric acid contains four nitrogen atoms, only a small amount of water is needed for its excretion. The enzyme xanthine oxidase makes uric acid from xanthine. 15. Shifting from ammonotelism to ureotelism is seen in (a) Frog (b) Fishes (c) Snake (d) Protopterus Ans. (a)
32 EXCRETORY PRODUCTS AND THEIR ELIMINATION Sol. The shifting from ammonotelism to ureotelism is seen in frogs. In the tadpoles, the end product of nitrogen metabolism is ammonia which is easily disposed of by diffusion in surrounding water. After metamorphosis, however, the frog excretes most of the nitrogenous wastes in the form of urea and only a small amount of ammonia from their body. 16. Assertion: Sharks are said to be ammonotelic animals. Reason: Sharks can retain considerable amounts of ammonia in their blood. (a) If both assertion and reason are true and reason is the correct explanation of assertion. (b) If both assertion and reason are true but reason is not the correct explanation of assertion. (c) If assertion is true but reason is false. (d) If both assertion and reason are false. Ans. (d) Sol. Shark is a ureotelic animal. They are required to regain urea in their blood so that they are hypertonic to marine water. Urea is toxic but sharks synthesize a substance which neutralizes its toxicity. Regaining of urea causes sodium and chloride ions out of their bodies and sharks are able to swim in marine water. Water loss is also minimised this way. Since sharks have to conserve water, they cannot eliminate ammonia as their nitrogenous waste as it requires a lot of water. Human Excretory System 17. The position of kidneys is (a) Last thoracic and third lumber vertebra (b) 11 th thoracic and second lumber vertebra (c) First and third lumber vertebra (d) Eighth thoracic and first lumber vertebra. Ans. (a) Sol. The kidneys are lying retroperitoneally (behind the peritoneum) in the abdomen, on either side of the vertebral column. Kidneys are reddish brown, bean shaped structures situated between the levels of last thoracic and third lumbar vertebra close to the dorsal inner wall of the abdominal cavity. 18. Notch present on inner medial side of kidney is known as (a) Ureter (b) Pelvis (c) Hilum (d) Pyramid Ans. (c) Sol. Hilum is a notch present in the medial concave border of the kidney from where nerves, blood vessels and some other ducts enter and exit. 19. The DCTs of many nephrons open into a straight tube called collecting duct. Many of which converge and finally open into (a) Renal pelvis (b) Duct of Bellini (c) Columns of Bertini (d) Central collecting duct Ans. (a) Sol. The distal convoluted tubules (DCT) of many nephrons open into a straight tube called collecting duct. Many of which converge and open into renal pelvis through medullary pyramids in the calyces. 20. The efferent arteriole emerging from the glomerulus forms a fine capillary network around the renal tubule called as (a) Vasa recta (b) Paratubular capillaries (c) Counter-current mechanism (d) Peritubular Capillaries Ans. (d) Sol. Peritubular capillaries are tiny blood vessels that travel along with nephrons. They surround the proximal and distal tubules and Henle’s loop where they are known as vasa recta, where peritubular capillaries reabsorb the ions and minerals. 21. Number of nephrons in each kidney of man is about (a) 2000 (b) 2 lakhs (c) 10-12 lakhs (d) Several lakhs Ans. (c) Sol. Based on autopsy specimens from individuals representing various ethnic groups, a large variation in nephron number exists in the normal adult human kidney, such that each kidney contains anywhere from 10 to 12 lakhs nephrons. 22. The double walled cup –like structure which encloses the tuft of capillaries is called (a) Malpighian body (b) Renal corpuscle (c) Bowman’s capsule (d) both (a) and (b) Ans. (c)
33 EXCRETORY PRODUCTS AND THEIR ELIMINATION Sol. The double walled cup –like structure which encloses the tuft of capillaries (glomerulus) is called Bowman’s capsule. Bowman’s capsule and glomerulus together form malpighian body or renal corpuscle. 23. Assertion: Nephrons are of two types cortical and juxtamedullary according to their relative location. Reason: Juxtamedullary nephrons have short loop of Henle while cortical nephrons have long loop of Henle. (a) If both assertion and reason are true and reason is the correct explanation of assertion. (b) If both assertion and reason are true but reason is not the correct explanation of assertion. (c) If assertion is true but reason is false. (d) If both assertion and reason are false. Ans. (c) Sol. There are two types of nephrons: cortical nephrons (85%) and juxtamedullary nephrons (15%), Cortical nephron is a microscopic structural and functional unit of the kidney with a short loop of Henle. Juxtamedullary nephron is a microscopic structural and functional unit of the kidney with a long loop of Henle. Cortical nephrons have a short loop of Henle, which penetrates only the outer renal medulla. 24. Length, width and thickness of the adult human kidney are approximately (a) 12-16 cm, 10-12 cm and 4-6 cm respectively (b) 10-12 cm, 5-7 cm and 2-3 cm respectively (c) 10-12 cm, 2-3 cm and 5-7 cm respectively (d) 12-16 cm, 5-7 cm and 2-3 cm respectively Ans. (b) Sol. The length, width, and thickness of the adult human kidney are approximately 10-12 cm, 5-7 cm, and 2-3 cm respectively. The length, width, and thickness of the kidney depend on different factors such as the number of renal arteries, BMI, height, gender, etc. 25. Average weight of kidney is about (a) 1.2 to 1.5 kg (b) 1.2 to 1.7 kg (c) 0.12 to 0.15 kg (d) 0.12 to 0.17 kg Ans. (d) Sol. The kidneys of an adult human measure to be around 120 to 170 gm or 0.12 to 0.17 kg each. Their length is 10 to 12 cm and width is 2 to 3 cm. Right kidney is slightly lower than the position of left kidney, due to the presence of liver. 26. Recognise the figure and find out the correct statement. (a) ‘a’ is the fine branch of renal vein (b) ‘b’ carried blood towards the glomerulus (c) ‘c’ is the tuft of capillaries formed by the ‘a’ (d) ‘d’ is a highly coiled network of renal tubule Ans. (d) Sol. In the figure, ‘d’ is a PCT, a highly coiled network of renal tubules. The tubule consists of different regions each with its own important function. The nephron begins as a cup-like structure called the bowman’s capsule where the glomerulus sits. Afferent arteriole carries blood towards kidney. Efferent arteriole carries blood away from the kidney. 27. Recognise the figure and find out the correct matching.