CBSE Class 10 Science Life Processes VBQs Set 03

Respiration

Question. In living organisms during respiration which of the following products are not formed if oxygen is not available?
(a) Carbon dioxide + Water
(b) Carbon dioxide + Alcohol
(c) Lactic acid + Alcohol
(d) Carbon dioxide + Lactic acid
Answer: (a) Carbon dioxide + Water

Question. The fermentation of glucose by yeast normally yields
(a) alcohol, \( CO_2 \) and 36 ATP
(b) \( CO_2 \), \( H_2O \) and 36 ATP
(c) alcohol, \( CO_2 \) and 2ATP
(d) lactic acid, \( CO_2 \) and 2 ATP
Answer: (c) alcohol, \( CO_2 \) and 2ATP

Question. A large quantity of one of the following is removed from our body by lungs:
(a) \( CO_2 \) and \( H_2O \)
(b) \( CO_2 \) only
(c) \( H_2O \) only
(d) ammonia
Answer: (a) \( CO_2 \) and \( H_2O \)

Question. In respiration, air passes through
(a) Pharynx \( \to \) nasal cavity \( \to \) larynx \( \to \) trachea \( \to \) bronchi \( \to \) bronchioles
(b) Nasal cavity \( \to \) pharynx \( \to \) larynx \( \to \) trachea \( \to \) bronchi \( \to \) bronchioles
(c) Larynx \( \to \) nasal cavity \( \to \) pharynx \( \to \) trachea
(d) Larynx \( \to \) pharynx \( \to \) trachea \( \to \) lungs
Answer: (b) Nasal cavity \( \to \) pharynx \( \to \) larynx \( \to \) trachea \( \to \) bronchi \( \to \) bronchioles

Question. A biochemical compound that readily combines with oxygen and distributes it throughout the human body is
(a) water
(b) urea
(c) haemoglobin
(d) acetylcholine
Answer: (c) haemoglobin

Question. Which row in the table below shows the correct products of anaerobic respiration in humans and in yeast?

(a) (a)
(b) (b)
(c) (c)
(d) (d)
Answer: (b) (b)

Question. Read the following statements.
X: Amount of carbon dioxide produced per molecule of glucose during aerobic respiration.
Y: Amount of carbon dioxide produced per molecule of glucose during fermentation by yeast.
Which of the following is TRUE about X and Y?
(a) X is more than Y.
(b) X is less than Y.
(c) X is equal to Y.
(d) Cannot be determined.
Answer: (a) X is more than Y.

Very Short Answer Type Questions

Question. Name two animals having cutaneous respiration. What special features of the skin make cutaneous respiration effective?
Answer: Frog and earthworm have cutaneous respiration. This respiration is effective because of presence of features like thin, moist and highly vascular skin which is also highly permeable to gases.

Question. How are inspiration and expiration brought about in human beings?
Answer: Inspiration is brought about by contraction of diaphragm muscles and some intercostal muscles. The diaphragm moves downward and the intercostal muscles move the lateral walls of thorax outward and upward. The volume of thorax increases and the air pressure is decreased. So, air is drawn into the lungs.
Expiration is brought about when the contracted muscles of diaphragm and intercostal muscles relax, the diaphragm moves upward and the lateral walls, move inward and downward. This decreases the volume of thorax and increases the air pressure. So, air is sent out of lungs.

Question. If one holds his breath after expiration for about 30 sec., would there still be occurring any exchange of respiratory gases in the lungs during this period? Explain.
Answer: The exchange of gases will continue. Even after forceful expiration, some volume of air remains in the lungs, which is called residual volume. Exchange of gases continues because of this air.

Question. Arthropods and molluscs have a copper-containing respiratory pigment called hemocyanin while human beings have iron-containing hemoglobin.
(a) How do respiratory pigments help in the process of respiration?
(b) Why do multicellular animals need a respiratory pigments?
Answer: (a) Respiratory pigments combine with oxygen and help in transport of oxygen throughout the body.
(b) When the body size of animals is large, diffusion pressure alone cannot take care of oxygen delivery to all parts of the body. Hence, respiratory pigments take up oxygen from the air in the lungs and carry it to tissues which are deficient in oxygen.

Short Answer Type Questions

Question. (a) Why do the walls of a trachea not collapse when there is less air in it?
(b) How are lungs designed in human beings to maximise the area for exchange of gases?
Answer: (a) The walls of trachea does not collapse when there is less air in it as it is supported by rings of soft bones of cartilage.
(b) There are millions of alveoli in the lungs. There alveolus provides a very large surface area for the exchange of gases. The availability of large surface area maximises the exchange of gases. For example, if all the alveoli from the two human lungs are unfolded, they would give an area of about 80 square meters.

Long Answer Type Questions

Question. (a) Write the reaction that occurs when glucose breaks down anaerobically in yeast.
(b) Write the mechanism by which fishes breath in water.
(c) Name the balloon likes structures present in lungs. List its two functions.
(d) Name the respiratory pigment and write its role in human beings.
Answer: (a) Glucose \( \xrightarrow{\text{In the Cytoplasm}} \) Pyruvate \( \xrightarrow{\text{In the Cytoplasm}} \) Ethanol + carbon dioxide + Energy.
(b) Fishes breathe with gills by diffusion.
(c) Alveoli are the balloon-like structures.

• They provide a surface for exchange of gases.
• They contains a residual volume of air so that there is sufficient time for exchange of gases.

(d) Haemoglobin is the respiratory pigment in humans. It transports a major part of oxygen and some amount of carbon dioxide through blood.

PRACTICE QUESTIONS

Question. In humans, carbon dioxide that is excreted passes from the blood directly into the
(a) trachea
(b) kidneys
(c) alveoli
(d) liver
Answer: (c) alveoli

Question. With a schematic diagram, explain the overall process of respiration.
Answer: [Schematic diagram illustrating the steps of respiration: Breathing (gas exchange), internal respiration (transport), and cellular respiration (glucose breakdown to energy).]

Question. Differentiate between left lung and right lung of humans.
Answer: The right lung is larger and consists of three lobes, whereas the left lung is smaller, has two lobes, and features a cardiac notch to accommodate the heart.

Question. (a) Describe the mechanism of breathing in human beings.
(b) (i) Under normal conditions, what is the rate of breathing per minute?
(ii) Why does the rate of breathing increase by 20 to 25 times during vigorous exercise?
Answer: (a) Breathing involves inhalation (inspiration) and exhalation (expiration). During inhalation, the diaphragm and intercostal muscles contract, increasing thoracic volume and lowering pressure, drawing air in. During exhalation, these muscles relax, decreasing volume and increasing pressure, pushing air out.
(b) (i) The normal breathing rate is approximately 12 to 16 times per minute.
(ii) During vigorous exercise, the body's demand for energy increases. To meet this demand, cellular respiration speeds up, requiring more oxygen and producing more \( CO_2 \). The breathing rate increases to rapidly supply oxygen and remove excess \( CO_2 \).

Question. Explain the process by which inhalation occurs during breathing in human beings.
Answer: Inhalation occurs when the diaphragm contracts and moves downwards, and the external intercostal muscles contract to lift the ribs upwards and outwards. This increases the volume of the thoracic cavity, leading to a decrease in air pressure inside the lungs compared to the atmosphere. Consequently, air flows into the lungs to equalize the pressure.

Question. Complete the following:
Glucose (6-carbon molecule) \( \xrightarrow{\text{In cytoplasm}} \) Pyruvate (3-carbon molecule) + energy
\( \xrightarrow{\text{Absence of Oxygen (in yeast)}} \) a
\( \xrightarrow{\text{Leak of Oxygen (in our muscle cells)}} \) b
\( \xrightarrow{\text{Presence of Oxygen (in mitochondria)}} \) c
(a) Ethanol and carbon dioxide
(b) Lactic acid
(c) Carbon dioxide and water
Answer: (a) Ethanol and carbon dioxide, (b) Lactic acid, (c) Carbon dioxide and water

Transportation

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. In a closed circulatory system, blood is completely enclosed within
(a) vessels
(b) heart
(c) skeleton
(d) sinuses
Answer: (a) vessels

Question. Which row of the table given below correctly gives the movement of gases across blood and cells?

(a) P
(b) Q
(c) R
(d) S
Answer: (d) S

Question. The process in which loss of water takes place in the form of water vapour through stomata is called
(a) transportation
(b) transpiration
(c) guttation
(d) translocation
Answer: (b) transpiration

Question. In a closed circulatory system, blood is completely enclosed within
(a) vessels
(b) heart
(c) skeleton
(d) sinuses
Answer: (b) Blood is completely enclosed within blood vessels in closed circulatory system.

Question. Normal blood pressure (systolic/diastolic) is
(a) 120/80 mm of Hg
(b) 160/80 mm of Hg
(c) 120/60 mm of Hg
(d) 180/80 mm of Hg
Answer: (a) Normal blood pressure is 120/80 mm of Hg

Question. Blood pressure is measured by an instrument called
(a) barometer
(b) sphygmomanometer
(c) photometer
(d) manometer
Answer: (b) Sphygmomanometer is an instrument used to measure blood pressure.

Very Short Answer Type Questions

Question. Name the water and mineral conducting element of non-flowering plants. Mention how conduction takes place in it.
Answer: Tracheids are the conducting cells of non-flowering plants. They are long, thin, spindle-shaped cells having pits in their thick cell walls. In them, water flows from one tracheid to other through these pits.

Question. Write down any two differences between the transport of materials in xylem and phloem.
Answer:

Question. A major portion of the carbohydrates produced by plants is stored in different parts of the plant (storage organs). Explain the mechanism by which this stored food is made available when different organs need it for growth.
Answer: Sugar from storage organ is moved to phloem using energy. This increases osmotic pressure of phloem. As a result water enters into the phloem. Increased pressure inside the phloem cells moves sugar to cells with lower pressure to reach other organs.

Short Answer Type Questions

Question. Mention the three kinds of cells present in blood. Write one function of each.
Answer: Blood is made up of plasma and corpuscles. Three kind of cells are: WBC, RBC and Blood platelets.

• Red Blood cells (RBC) are small, biconcave cells that contain haemoglobin to transport \( O_2 \) from the lungs to the body cells and \( CO_2 \) from body cells to the lungs.
• White blood cell’s (WBC) main function is defence of the body against diseases and other infection.
• Blood platelets are responsible for the clotting of blood during injuries.

Question. List the three kinds of blood vessels of human circulatory system and write their functions in tabular form. Or Write three types of blood vessels. Give one important feature of each.
Answer: Three types of blood vessels in human circulatory system are Arteries, Veins and Capillaries. Their functions are tabulated below:

Question. Write one function of each of the following components of the transport system in human beings: (a) Blood vessels (b) Lymph (c) Heart
Answer: Function of the following components of the transport system in human beings are as follows:
(a) Blood vessels: There are three types of blood vessels of different sizes involved in blood circulation viz. arteries, veins and capillaries, which are all connected to form a continuous closed system.
(b) Lymph: It carries digested and absorbed fat from intestine and drains excess fluid from extra cellular space back into the blood.
(c) Heart: It is a pumping organ that receives blood from the veins and pumps it into the arteries.

Question. What is blood pressure? How it is measured? Give one difference between systolic pressure and diastolic pressure.
Answer: Blood Pressure: It is the force that blood exerts against the wall of a vessel. This pressure is much greater in arteries than in veins. It is measured by using an instrument called sphygmomanometer. The pressure of blood inside artery during contraction or ventricular systole is called systolic pressure and pressure in artery during relaxation or ventricular diastole is called diastolic pressure. The normal systolic pressure is about \( 120 \) mm of \( Hg \) and diastolic pressure is \( 80 \) mm of \( Hg \).

Question. (a) What is double circulation? (b) Why is the separation of the right side and the left side of the heart useful? How does it help birds and mammals?
Answer: (a) The circulatory system of man is called double circulation as the blood passes through the heart twice in one complete cycle of the body.
(b) The right side and the left side of the human heart are useful to prevent deoxygenated and oxygenated blood from mixing. This type of separation of oxygenated and deoxygenated blood ensures a highly efficient supply of oxygen to the body. This is useful in case of birds and mammals because it constantly gives energy to maintain their body temperature.

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 fat from the intestine and drains excess fluid from extracellular space back into the blood. Blockage of lymphatic system will lead to water retention and poor fat absorption in the body.

Question. Human beings exhibit ‘double circulation’ during which blood is passed through the lungs and heart. (a) State the route of the first and the second circulation through the chambers of the heart and explain the usefulness of such circulation in humans. (b) Name the blood vessels that: (i) carry oxygenated blood from the lungs to the heart. (ii) carry deoxygenated blood from the heart to the lungs.
Answer: (a) During first circulation oxygenated blood from lungs come to the left atrium to left ventricle to pass to the body. During second circulation deoxygenated blood from body comes to right atrium and then right ventricle to pass for oxygenation to the lungs again. Double circulation allows for separation of oxygenated and deoxygenated blood in the body.
(b) (i) Pulmonary vein (ii) Pulmonary artery

Long Answer Type Questions

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) Blood is composed of plasma and three types of cells—Red blood cells, white blood cells and platelets.
(b) Oxygenated blood from the lungs is brought to the left atrium by pulmonary veins. When the atrium contracts, blood is transferred to left ventricle. When the ventricle contracts, blood is pushed into the aorta and through arteries to all parts of the body.
(c) The valves prevent the backflow of blood from ventricles into atria.
(d) Arteries: (i) They have thick elastic walls. (ii) They have no internal valves. Veins: (i) They are thin walled. (ii) They have valves internally.

Question. (a) Name the blood vessel that brings oxygenated blood to the human heart. (b) Which chamber of human heart receives oxygenated blood? (c) Explain how oxygenated blood from this chamber is sent to all parts of the body.
Answer: (a) The pulmonary vein brings oxygenated blood to the human heart.
(b) The left auricle of human heart receives oxygenated blood.
(c) (i) When oxygenated blood comes into the left atrium, it contracts and pours blood into left ventricle. (ii) The left ventricle contracts and the oxygenated blood from here is distributed to all parts of the body through aorta.

Question. Explain the various functions of blood.
Answer: Functions of Blood — Blood performs the following functions:
(i) Transport of Oxygen: Red blood corpuscles contain haemoglobin that combines with oxygen to form oxyhaemoglobin which is transported to the tissues of the body for the purpose of respiration.
(ii) Transport of Carbon dioxide: Carbon dioxide produced by the tissues as a result of respiration is transported by the blood plasma and also by the haemoglobin to the lungs from where it is removed.
(iii) Transport of Nutrients: The digested and absorbed nutrients like glucose, amino acids, fatty acids, vitamins, etc. are first transported to the liver and then to the whole of tissues for their storage, oxidation and synthesis to new substances.
(iv) Transport of Excretory Products: Nitrogenous wastes like ammonia, urea and uric acid of body are transported to the kidneys by the blood from where they are eliminated.
(v) Regulation of Body Temperature: The blood flows in all parts of the body, so it equalises the body temperature. It carries heat produced from one place to another place of the body.
(vi) Maintenance of pH: The plasma proteins act as buffer system and maintain required pH of the body tissues.
(vii) Transport of Hormones: The plasma of blood transports various hormones from one region to another and brings about the co-ordination in the working of the body.
(viii) Water Balance: The blood maintains water balance at constant level by distributing uniformly over the body.
(ix) Protection from Diseases: The WBCs (eosinophils, neutrophils, monocytes) engulf the bacteria and other disease causing organisms by phagocytosis. The lymphocytes produce antibodies against the invading antigens.
(x) Clotting of Blood: Blood forms a clot at the site of injury, thus preventing further loss of blood. Blood helps in rapid healing of wounds.