CBSE Class 10 Science Life Processes VBQs Set 05

SA I

Question. (a) In the process of respiration, state the function of alveoli.
(b) Rate of breathing in aquatic organisms is much faster than that in terrestrial organisms. Give reasons.
(c) Complete the following pathway showing the breakdown of glucose.
\[ \text{Glucose (6-carbon molecules)} \xrightarrow{\text{in cytoplasm}} \text{(i) } \text{? (3-carbon molecule + energy)} \xrightarrow[\text{in mitochondria}]{\text{Presence of } O_2} \text{(ii) } \text{? } + H_2O + \text{Energy} \]
Answer: (a) Alveoli provide a very large and thin surface area for the exchange of gases (\( O_2 \) and \( CO_2 \)) between the air and the blood capillaries surrounding them.
(b) The amount of dissolved oxygen in water is fairly low compared to the amount of oxygen in the air. Therefore, aquatic organisms have to breathe faster to get enough oxygen for their requirements.
(c) (i) Pyruvate, (ii) Carbon dioxide (\( CO_2 \))

Question. Explain the ways in which glucose is broken down in absence or shortage of oxygen.
Answer: 1. In the absence of oxygen: In organisms like yeast, glucose is first converted to pyruvate in the cytoplasm and then into ethanol, carbon dioxide, and energy (Fermentation).
2. In shortage of oxygen: In our muscle cells, when there is a lack of oxygen during heavy exercise, glucose is converted to pyruvate and then into lactic acid and energy. Accumulation of lactic acid causes muscle cramps.

Question. Write three points of difference between breathing and respiration.
Answer:

• Breathing: 1. It is a physical process of inhalation and exhalation. 2. It takes place outside the cells (extracellular). 3. No energy is released.
• Respiration: 1. It is a biochemical process of oxidation of food to release energy. 2. It takes place inside the cells (intracellular). 3. Energy is released in the form of ATP.

Question. Write three points of difference between respiration in plants and respiration in animals.
Answer:

• Respiration in Plants: 1. Respiration occurs through individual parts like leaves (stomata), stems (lenticels), and roots. 2. There is little transport of gases from one part to another. 3. It occurs at a slower rate.
• Respiration in Animals: 1. Respiration occurs as a single unit with specialized respiratory organs (lungs, gills, etc.). 2. Respiratory gases are transported long distances through blood. 3. It occurs at a much faster rate.

Question. In the experimental set up to show that “\( CO_2 \) is given out during respiration”, name the substance taken in the small test tube kept in the conical flask. State its function and the consequence of its use.
Answer: The substance taken in the small test tube is Potassium hydroxide (KOH).
Function: It absorbs the carbon dioxide released by the germinating seeds during respiration.
Consequence: As KOH absorbs the \( CO_2 \), it creates a partial vacuum in the conical flask. This causes the air pressure inside the flask to drop, leading to a rise in the water level in the delivery tube connected to the beaker of water.

Question. (a) State reasons for the following:
(i) Herbivores need a longer small intestine while carnivores have shorter small intestine.
(ii) The lungs are designed in human beings to maximise the area for exchange of gases.
(b) The rate of breathing in aquatic organisms is much faster than that seen in terrestrial organisms.
Answer: (a) (i) Herbivores eat grass which is rich in cellulose. Cellulose is difficult to digest and takes a longer time; hence they need a longer small intestine. Carnivores eat meat which is easier to digest, so they have a shorter small intestine.
(ii) Within the lungs, the passage divides into smaller and smaller tubes which finally terminate in balloon-like structures called alveoli. The alveoli provide an extensive surface area (nearly 80 square meters) where the exchange of gases can take place efficiently.
(b) Refer to the answer of the previous question (49a).

Transportation

MCQ

Question. The process in which loss of water in the form of vapours from the aerial parts of plants takes place is X, which helps in Y. Here, X and Y respectively are
(a) transpiration and photosynthesis
(b) transpiration and temperature regulation
(c) translocation and movement of soluble products of photosynthesis in phloem
(d) translocation and absorption of water and minerals from soil by roots.
Answer: (b) transpiration and temperature regulation

Question. Assertion (A) : The walls of atria are thicker than those of the ventricles.
Reason (R) : Ventricles have to pump blood into various organs at high pressure.
(a) Both Assertion (A) and Reason (R) are true and Reason (R) is the correct explanation of the Assertion (A)
(b) Both Assertion (A) and Reason (R) are true, but Reason (R) is not the correct explanation of the Assertion (A)
(c) Assertion (A) is true, but Reason (R) is false.
(d) Assertion (A) is false, but Reason (R) is true.
Answer: (d) Assertion (A) is false, but Reason (R) is true.

Visible movements only cannot be the defining characteristic of life. Molecular movements which are invisible to the naked eye are necessary for life. Viruses are said to be living as they also show molecular movements but only when they are inside a living cell. Living organisms are organised structures. They must keep repairing and maintaining their structures. Maintenance of an organism is the collection of processes like nutrition, respiration, etc. In absence of any one of these, life would be difficult. To remain alive, chemical energy is needed by the living organism to perform vital process. It provides energy to (a) maintain life processes, (b) produce molecules for repair of worn out cells, and (c) for the growth of the body.

Question. Viruses show molecular movements when they are
(a) in crystalline form
(b) inside a dead material
(c) in air
(d) in the body of a living organism.
Answer: (d) in the body of a living organism.

Question. The process which involves intake of \( O_2 \) from outside and breaking down of nutrient molecules to produce energy is called
(a) excretion
(b) nutrition
(c) respiration
(d) reproduction.
Answer: (c) respiration

Question. Which one of the following statements is incorrect? Energy is needed by a living organism to
(a) maintain life processes
(b) grow
(c) repair worn out tissues of the body
(d) synthesise waste materials.
Answer: (d) synthesise waste materials.

Question. The type of nutrition found in green plants is
(a) autotrophic
(b) heterotrophic
(c) parasitic
(d) holozoic.
Answer: (a) autotrophic

Question. The function of the circulatory system of human beings is to transport
(a) food
(b) oxygen
(c) waste material
(d) all of the options.
Answer: (d) all of the options.

Question. The separation of the right side and the left side of heart is useful to
(a) keep oxygenated blood from mixing with deoxygenated blood
(b) allow a slow supply of oxygen in the body
(c) supply energy to animals with low energy needs
(d) often change their body temperature.
Answer: (a) keep oxygenated blood from mixing with deoxygenated blood

Question. In spring, sugar stored in root or stem tissue of plants is transported to the buds for
(a) the energy needs of the buds to grow
(b) temperature regulation
(c) balancing the storage in different organs
(d) diffusion process.
Answer: (a) the energy needs of the buds to grow

Question. Upward movement of water in tall trees is due to
(a) translocation
(b) excretion
(c) photosynthesis
(d) transpiration.
Answer: (d) transpiration.

Question. Thin walled blood vessels are called
(a) aorta
(b) capillaries
(c) arteries
(d) vena cava.
Answer: (b) capillaries

Question. Identify the two components of phloem tissue that help in transportation of food in plants.
(a) Phloem parenchyma and sieve tubes
(b) Sieve tubes and companion cells
(c) Phloem parenchyma and companion cells
(d) Phloem fibres and sieve tubes
Answer: (b) Sieve tubes and companion cells

Question. Which one of the following statements is correct about the human circulatory system?
(a) Blood transports only oxygen and not carbon dioxide.
(b) Human heart has five chambers.
(c) Valves ensure that the blood does not flow backwards.
(d) Both oxygen-rich and oxygen-deficient blood gets mixed in the heart.
Answer: (c) Valves ensure that the blood does not flow backwards.

VSA 

Question. Name the vein which brings blood to left atrium from the lungs.
Answer: Pulmonary vein.

Question. Define translocation in reference to plants.
Answer: Translocation is the transport of soluble products of photosynthesis (sucrose/food) from the leaves to other parts of the plant through the phloem.

SA I 

Question. What is the other name of tissue fluid? Write its two functions.
Answer: The other name for tissue fluid is Lymph.
Functions:
1. It carries digested and absorbed fat from the intestine.
2. It drains excess fluid from extracellular space back into the blood.

Question. What will happen if:
(a) Xylem tissue in a plant is removed?
(b) We are injured and start bleeding?
Answer: (a) If xylem tissue is removed, the upward transport of water and minerals from the roots to the leaves will stop. Consequently, the plant will not be able to perform photosynthesis and will eventually wilt and die. (b) If we are injured and start bleeding, the platelets in our blood help in the formation of a clot at the site of injury. This prevents excessive loss of blood from the system and also prevents entry of pathogens.

SA II 

Question. (i) What is double circulation?
(ii) Why is the separation of the right side and the left side of the heart useful? How does it help birds and mammals?
Answer: (i) Double circulation is a process in which blood passes through the heart twice during one complete cycle through the body. It consists of pulmonary circulation and systemic circulation. (ii) The separation of the right and left sides of the heart prevents the mixing of oxygenated and deoxygenated blood. This allows for a highly efficient supply of oxygen to the body, which is essential for birds and mammals to maintain their high energy needs and constant body temperature.

Question. (a) List in tabular form two differentiating features between xylem and phloem.
(b) Write two advantages of transpiration in plants.
Answer: (a)

(b) Two advantages of transpiration: 1. It helps in the upward movement of water and minerals by creating a suction pull (transpiration pull). 2. It helps in temperature regulation of the plant by providing a cooling effect.

Question. Write three types of blood vessels. Give one important feature of each.
Answer: The three types of blood vessels are: 1. Arteries: They have thick, elastic walls to carry blood under high pressure away from the heart. 2. Veins: They have valves that ensure blood flows in only one direction, towards the heart. 3. Capillaries: They have extremely thin walls (one-cell thick) to facilitate the exchange of materials between blood and surrounding cells.

Question. (a) Write two water conducting tissues present in plants. How does water enter continuously into the root xylem?
(b) Explain why plants have low energy needs as compared to animals.
Answer: (a) The two water conducting tissues are xylem tracheids and xylem vessels. At the roots, cells in contact with the soil actively take up ions. This creates a difference in the concentration of ions between the root and the soil. Water, therefore, moves into the root from the soil to eliminate this difference, creating a continuous column of water. (b) Plants have low energy needs because they do not move from one place to another. Also, a large proportion of plant tissues are dead (like xylem), which further reduces their overall energy requirement.

Question. List four functions of the human heart. Why is double circulation necessary in the human body?
Answer: Four functions of the human heart are: 1. Pumping oxygenated blood to all parts of the body. 2. Receiving deoxygenated blood from various body parts. 3. Sending deoxygenated blood to the lungs for oxygenation. 4. Maintaining blood pressure to ensure circulation. Double circulation is necessary because it ensures a complete separation of oxygenated and deoxygenated blood, providing a highly efficient supply of oxygen to meet the high energy demands of the human body.

Question. Explain how the translocation of materials in phloem tissue in plants is achieved by utilising energy.
Answer: Translocation in phloem is an active process. Sucrose is transferred into phloem tissue using energy from ATP. This increases the osmotic pressure of the tissue, causing water to move into it. This pressure moves the material in the phloem to tissues which have less pressure. This allows the phloem to move material according to the plant's needs.

Question. What do the following transport?
(i) Xylem
(ii) Phloem
(iii) Pulmonary vein
(iv) Vena cava
(v) Pulmonary artery
(vi) Aorta
Answer: (i) Xylem: Water and minerals. (ii) Phloem: Food (sucrose) and amino acids. (iii) Pulmonary vein: Oxygenated blood from lungs to left atrium. (iv) Vena cava: Deoxygenated blood from body parts to right atrium. (v) Pulmonary artery: Deoxygenated blood from right ventricle to lungs. (vi) Aorta: Oxygenated blood from left ventricle to the rest of the body.

Question. Explain giving any three reasons the significance of transpiration in plants.
Answer: The significance of transpiration in plants includes: 1. It creates a transpiration pull that helps in the upward movement of water and dissolved minerals from roots to leaves. 2. It helps in the regulation of temperature by providing a cooling effect through evaporation. 3. It helps in the removal of excess water from the plant body.

LA 

Question. (i) Plants absorb water from the soil. Explain how it is taken up and transported from the soil.
(ii) “When we are injured and start bleeding, it requires the loss of blood from the system to be minimised.” What will happen if the blood loss is not stopped? Is there anything the system would do on its own to prevent the loss?
Answer: (i) Water is absorbed by root hairs via osmosis due to the concentration gradient created by active absorption of ions. It then moves through the root layers into the xylem. Transpiration pull further draws this water column upwards to reach the aerial parts of the plant. (ii) If blood loss is not stopped, the blood pressure would decrease, reducing the efficiency of the pumping system. This can lead to shock and eventually death. The system prevents loss through platelets, which circulate in the blood and help in clotting by plugging the leaks at the site of injury.

Question. Give reasons:
(a) Ventricles have thicker muscular walls than atria.
(b) Transport system in plants is slow.
(c) Circulation of blood in aquatic vertebrates differs from that in terrestrial vertebrates.
(d) During the daytime, water and minerals travel faster through xylem as compared to the night.
(e) Veins have valves whereas arteries do not.
Answer: (a) Ventricles have to pump blood into various organs of the body at high pressure, whereas atria only need to pump blood into the ventricles. (b) Plants are stationary and have a large proportion of dead cells in many tissues; thus, they have low energy needs and do not require a fast transport system. (c) Aquatic vertebrates like fish have a two-chambered heart and single circulation, while terrestrial vertebrates like mammals have three or four-chambered hearts and double circulation to maintain high energy needs. (d) During the daytime, stomata are open, and transpiration rate is high, creating a strong transpiration pull. At night, stomata are closed, so the pull is much weaker. (e) Arteries carry blood away from the heart under high pressure, so blood flows in one direction. Veins carry blood towards the heart under low pressure, so valves are necessary to prevent backflow.

Question. (a) Blood circulation in fishes is different from the blood circulation in human beings”. Justify the statement.
(b) Describe “blood circulation” in human beings.
Answer: (a) Fishes have a two-chambered heart and blood is pumped to the gills for oxygenation and then directly to the rest of the body, meaning blood passes through the heart only once (single circulation). Humans have a four-chambered heart with double circulation (pulmonary and systemic). (b) In humans, deoxygenated blood from the body enters the right atrium, goes to the right ventricle, and is pumped to the lungs via the pulmonary artery. Oxygenated blood from the lungs returns via the pulmonary vein to the left atrium, goes to the left ventricle, and is pumped to the body via the aorta.

Question. (a) Mention any two components of blood.
(b) Trace the movement of oxygenated blood in the body.
(c) Write the function of valves present in between atria and ventricles.
(d) Write one structural difference between the composition of artery and veins.
Answer: (a) Two components of blood are Plasma and Blood Cells (RBCs, WBCs, and Platelets). (b) Lungs \( \implies \) Pulmonary vein \( \implies \) Left atrium \( \implies \) Left ventricle \( \implies \) Aorta \( \implies \) Body tissues/organs. (c) The valves (tricuspid and bicuspid) prevent the backflow of blood from the ventricles into the atria when the ventricles contract. (d) Arteries have thick, elastic muscular walls, whereas veins have thinner walls and possess valves to prevent backflow.

Excretion

MCQ

Question. Which one among the following is not removed as a waste product from the body of a plant?
(a) Resins and gums
(b) Urea
(c) Dry leaves
(d) Excess water
Answer: (b) Urea