CBSE Class 10 Science Life Processes VBQs Set 06

waste products from the blood, such as excess salts, and urea which are insufficiently removed by the kidney in patients with kidney failure. During the procedure, the patient’s blood is cleaned by filtration through a series of semi-permeable membranes before being returned to the blood of the patient. On the basis of this answer the following questions.

Question. The haemodialyser has semi-permeable lining of tubes which help
(a) to maintain osmotic pressure of blood
(b) to filter nitrogenous wastes from the dialysing solution
(c) in passing the waste products in the dialysing solution
(d) to pump purified blood back into the body of the patient.
Answer: (c) in passing the waste products in the dialysing solution

Question. Which one of the following is not a function of artificial kidney?
(a) To remove nitrogenous wastes from the blood.
(b) To remove excess fluids from the blood.
(c) To reabsorb essential nutrients from the blood.
(d) To filter and purify the blood.
Answer: (c) To reabsorb essential nutrients from the blood.

Question. The ‘used dialysing’ solution is rich in
(a) urea and excess salts
(b) blood cells
(c) lymph
(d) proteins.
Answer: (a) urea and excess salts

Question. Which part of the nephron in human kidney, serves the function of reabsorption of certain substances?
(a) Glomerulus
(b) Bowman’s Capsule
(c) Tubules
(d) Collecting duct
Answer: (c) Tubules

SA I 

Question. Write one specific function of each of the following organs in relation with excretion in human beings :
(i) Renal Artery
(ii) Urethra
(iii) Glomerulus
(iv) Tubular part of nephron
Answer: (i) Renal Artery: It carries oxygenated blood loaded with nitrogenous wastes like urea and salts from the heart to the kidneys for filtration.
(ii) Urethra: It is a muscular tube through which urine collected in the urinary bladder is expelled out of the body.
(iii) Glomerulus: It acts as a primary filter where the ultrafiltration of blood occurs, allowing water and small solutes to pass into the Bowman's capsule.
(iv) Tubular part of nephron: It performs selective reabsorption of useful substances such as glucose, amino acids, and water from the filtrate back into the surrounding blood capillaries.

Question. Explain in brief two ways by which leaves of a plant help in excretion.
Answer: 1. Leaves store many cellular waste products in their vacuoles. When these leaves age and fall off, the plant gets rid of these wastes.
2. Leaves contain stomata through which gaseous waste products of photosynthesis (oxygen) and respiration (carbon dioxide) are released into the atmosphere.

SA II 

Question. (a) Define the term excretion. Why should animals excrete waste matter? (b) Name the main excretory organ of human beings and state the form in which the excretory matter is thrown out of the body?
Answer: (a) Excretion is the biological process involved in the removal of toxic metabolic waste products from the body. Animals need to excrete these wastes because their accumulation can be poisonous, disturb the internal chemical balance, and may lead to death.
(b) The main excretory organ in human beings is the pair of kidneys. The excretory matter is thrown out of the body in the form of a liquid called urine.

LA 

Question. (a) Describe the structure and function of the basic filtering unit of kidney. (b) List two factors on which reabsorption of water from urine depends.
Answer: (a) The basic filtering unit is the nephron. It comprises a glomerulus for filtration and a tubule for reabsorption. The glomerulus filters out water, salts, glucose, and nitrogenous wastes. The tubule selectively reabsorbs useful components and water back into the blood capillaries based on body requirements.
(b) Reabsorption of water depends on: 1. The amount of excess water present in the body tissues. 2. The amount of dissolved waste (like salts and urea) that needs to be excreted.

Question. (a) Name the organs that form the excretory system in human beings. (b) Describe in brief how urine is produced in human body.
Answer: (a) The human excretory system consists of a pair of kidneys, a pair of ureters, a urinary bladder, and a urethra.
(b) Urine production involves three main steps: 1. Ultrafiltration: High blood pressure in the glomerulus forces water and small solutes into the Bowman's capsule. 2. Selective Reabsorption: As filtrate moves through the tubule, glucose, amino acids, and water are reabsorbed. 3. Secretion: Certain ions and wastes are actively secreted into the tubule. The resulting concentrated liquid is urine.

Nutrition

Question. Opening and closing of stomatal pore depends on
(a) atmospheric temperature
(b) oxygen concentration around stomata
(c) carbon dioxide concentration around stomata
(d) water content in the guard cells.
Answer: (d) water content in the guard cells.

Question. In which of the following groups of organisms, food material is broken down outside the body and then absorbed in?
(a) Mushroom, green plants, Amoeba
(b) Yeast, mushroom, bread mould
(c) Paramecium, Amoeba, Cuscuta
(d) Cuscuta, lice, tapeworm
Answer: (b) Yeast, mushroom, bread mould

VSA 

Question. State the role of pancreas in digestion of food.
Answer: The pancreas secretes pancreatic juice which contains enzymes like trypsin for digesting proteins and pancreatic lipase for breaking down emulsified fats.

Question. How is the wall of small intestine adapted for performing the function of absorption of food?
Answer: The inner lining of the small intestine has numerous finger-like projections called villi, which increase the surface area for absorption. The villi are richly supplied with blood vessels to take the absorbed food to each and every cell of the body.

Question. Out of a goat and a tiger, which one will have a longer small intestine? Justify your answer.
Answer: A goat will have a longer small intestine. This is because goats eat grass, which contains cellulose. Cellulose is complex and takes a longer time to be digested, necessitating a longer small intestine. Tigers eat meat, which is easier to digest.

SA I

Question. Patients whose gall bladder are removed are recommended to eat less oily food. Why?
Answer: The gall bladder stores and concentrates bile juice, which is essential for the emulsification of fats. Without a gall bladder, the continuous secretion of bile from the liver may not be sufficient or properly timed to digest a large amount of oily food efficiently.

Question. Bile juice does not have any digestive enzyme but still plays a significant role in the process of digestion. Justify the statement.
Answer: Bile juice is significant because:
1. It contains bile salts that emulsify large fat globules into smaller ones, increasing the efficiency of pancreatic lipase.
2. It makes the acidic food coming from the stomach alkaline, so that pancreatic enzymes can act on it.

Question. State the events occurring during the process of photosynthesis. Is it essential that these steps take place one after the other immediately?
Answer: The main events are:
(i) Absorption of light energy by chlorophyll.
(ii) Conversion of light energy to chemical energy and splitting of water molecules into hydrogen and oxygen.
(iii) Reduction of carbon dioxide to carbohydrates.
No, it is not essential that these steps take place immediately one after the other. For example, desert plants take up carbon dioxide at night and prepare an intermediate which is acted upon by the energy absorbed by the chlorophyll during the day.

Respiration

All living cells require energy for various activities. This energy is available by the breakdown of simple carbohydrates either using oxygen or without using oxygen.

Question. Energy in the case of higher plants and animals is obtained by
(a) breathing
(b) tissue respiration
(c) organ respiration
(d) digestion of food.
Answer: (b) tissue respiration

Question. The characteristic processes observed in anaerobic respiration are
(i) presence of oxygen
(ii) release of carbon dioxide
(iii) release of energy
(iv) release of lactic acid.
(a) (i) and (ii) only
(b) (i), (ii) and (iii) only
(c) (ii), (iii) and (iv) only
(d) (iv) only
Answer: (c) (ii), (iii) and (iv) only

Transportation

Question. Assertion (A) : Amphibians can tolerate mixing of oxygenated and deoxygenated blood.
Reason (R) : Amphibians are animals with two chambered heart.
(a) Both (A) and (R) are true and (R) is the correct explanation of (A).
(b) Both (A) and (R) are true but (R) is not the correct explanation of (A).
(c) (A) is true but (R) is false.
(d) (A) is false but (R) is true.
Answer: (c) (A) is true but (R) is false.

Question. Identify the phase of circulation which is represented in the diagram of heart given below. Arrows indicate contraction of the chambers shown.
(a) Blood transferred to the right ventricle and left ventricle simultaneously.
(b) Blood is transferred to lungs for oxygenation and is pumped into various organs simultaneously.
(c) Blood transferred to the right auricle and left auricle simultaneously.
(d) Blood is received from lungs after oxygenation and is received from various organs of the body.
Answer: (a) Blood transferred to the right ventricle and left ventricle simultaneously.

Question. Assertion (A) : Resins and gums are stored in old xylem tissue in plants.
Reason (R): Resins and gums facilitate transport of water molecules.
(a) Both (A) and (R) are true and (R) is the correct explanation of (A).
(b) Both (A) and (R) are true but (R) is not the correct explanation of (A).
(c) (A) is true but (R) is false.
(d) (A) is false but (R) is true.
Answer: (c) (A) is true but (R) is false.

Question. In which of the following groups of organisms, blood flows through the heart only once during one cycle of passage through the body?
(a) Rabbit, parrot, turtle
(b) Frog, crocodile, pigeon
(c) Whale, Labeo, penguin
(d) Shark, dog fish, sting ray
Answer: (d) Shark, dog fish, sting ray

VSA 

Question. Veins are thin walled and have valves. Justify.
Answer: Veins carry blood towards the heart from various body parts under much lower pressure than arteries, so thick walls are not required. Valves are present to ensure that blood flows only in one direction—towards the heart—and prevent backflow.

SA I

Question. The leaves of a plant were covered with aluminium foil, how would it affect the physiology of the plant?
Answer: Covering leaves with aluminium foil will block sunlight and gaseous exchange. This will stop photosynthesis (leading to lack of food), stop transpiration (stopping the upward movement of water/minerals), and hinder respiration, ultimately causing the leaf or plant to die.

Question. How is lymph an important fluid involved in transportation? If lymphatic vessels get blocked, how would it affect the human body? Elaborate.
Answer: Lymph carries digested and absorbed fats from the intestine and drains excess fluid from extracellular space back into the blood. If lymphatic vessels are blocked, excess fluid will accumulate in the tissues, leading to severe swelling (edema) and impaired fat absorption.

Question. In birds and mammals, the left and right side of the heart are separated. Give reasons.
Answer: This separation prevents the mixing of oxygenated and deoxygenated blood. It allows for a highly efficient supply of oxygen to the body, which is necessary for maintaining a constant high body temperature in warm-blooded animals.

Excretion

Question. What is common between extensive network of blood vessels around walls of alveoli and in glomerulus of nephron?
(a) Thick walled arteries richly supplied with blood.
(b) Thin walled veins poorly supplied with blood.
(c) Thick walled capillaries poorly supplied with blood.
(d) Thin walled capillaries richly supplied with blood.
Answer: (d) Thin walled capillaries richly supplied with blood.

Question. Plants use completely different process for excretion as compared to animals. Which one of the following processes is not followed by plants for excretion?
(a) They can get rid of excess water by transpiration.
(b) They selectively filter toxic substances through their leaves.
(c) Waste products are stored as resins and gums in old xylem.
(d) They excrete waste substances into the soil around them.
Answer: (b) They selectively filter toxic substances through their leaves.

Question. In a person the tubule part of the nephron is not functioning at all. What will its effect be on urine formation?
(a) The urine will not be formed .
(b) Quality and quantity of urine is unaffected.
(c) Urine is more concentrated.
(d) Urine is more diluted.
Answer: (d) Urine is more diluted.

SA I 

Question. Name the substances other than water, that are reabsorbed during urine formation. What are the two parameters that decide the amount of water that is reabsorbed in the kidney?
Answer: Substances reabsorbed include glucose, amino acids, and salts. The two parameters are:
1. The amount of excess water in the body tissues.
2. The amount of dissolved waste (like urea and salts) to be excreted.

SA II 

Question. Explain where and how urine is produced?
Answer: Urine is produced in the kidneys by nephrons. The process involves:
1. Ultrafiltration: Blood is filtered in the glomerulus under pressure, removing water, salts, glucose, and urea into the Bowman’s capsule.
2. Selective Reabsorption: As filtrate flows through the tubule, useful substances like glucose and water are reabsorbed back into the blood.
3. Secretion: Waste products are secreted into the tubule, forming urine, which flows to the bladder.

Case Based Questions

Read the passage given below and answer the following questions : Given are the sections of two pipes, A and B. If you need to represent blood vessels with these, which of the pipes would correspond to the artery and which one to a vein. Identify it and answer the following questions.

Question. B is best defined as the vessel which
(a) always supply oxygenated blood to the different organs
(b) always carry blood away from the heart to different organs
(c) always break up into capillaries that reunite to form a vein
(d) always carry blood from one visceral organ to another visceral organ.
Answer: (b) always carry blood away from the heart to different organs

Question. In A, valves are present to check backward flow of blood flowing at
(a) atmospheric pressure
(b) high pressure
(c) low pressure
(d) All of the options.
Answer: (c) low pressure

Question. Which of the following statements is correct regarding A?
(a) Carries blood from an organ towards the heart.
(b) Always carry oxygenated blood with single exception.
(c) Carries blood from heart towards the organ.
(d) All of the options
Answer: (a) Carries blood from an organ towards the heart.

Question. Which of the following statements is incorrect?
(a) A has typically larger lumen than B.
(b) Walls of B are elastic enabling them to stretch and shrink during changes in blood pressure.
(c) Flow of blood is slower in A than in B.
(d) None of the options
Answer: (d) None of the options

Question. Blood pressure in the pulmonary artery is
(a) more than that of pulmonary vein
(b) less than that in the vena cava
(c) same as that in aorta
(d) less than pulmonary vein.
Answer: (a) more than that of pulmonary vein

Read the passage given below and answer the following questions :
Double circulation is a type of circulating system in which the blood passes through the heart twice before completing a full circuit of the body. Blood is pumped from the heart to the lungs and returns to the heart before being distributed to other organs and tissues of the body.

Question. What is the role of four chambers of heart in double circulation?
Answer: The four-chambered heart ensures complete separation of oxygenated and deoxygenated blood. The right side (atrium and ventricle) receives and pumps deoxygenated blood to the lungs, while the left side (atrium and ventricle) receives and pumps oxygenated blood to the rest of the body. This separation prevents the mixing of blood and allows for a highly efficient supply of oxygen to the body tissues.

Question. Enlist two animals that shows double circulatory pathway.
Answer: Humans (mammals) and Birds.

Question. Write the correct sequence of pulmonary circulation.
Answer: Right Ventricle
\( \implies \) Pulmonary Artery
\( \implies \) Lungs
\( \implies \) Pulmonary Vein
\( \implies \) Left Atrium.