Class 10 Life Processes Mock Test (CBSE)

Topics in Life Processes

• Autotrophic nutrition
• Heterotrophic nutrition
• Nutrition in human beings
• Respiration
• Transportation in human beings
• Transportation in plants
• Excretion in human beings
• Excretion in plants

Life Processes practice questions with answers

1. Q1Multiple choice·1 mark
   A student sets up an experiment to test the requirements of photosynthesis. A destarched potted plant is placed in sunlight. One of its leaves is enclosed in a conical flask containing potassium hydroxide ($\text{KOH}$) solution, while another leaf is exposed to normal atmospheric air. After a few hours, an iodine test is performed on both leaves. What is the scientific purpose of using $\text{KOH}$ in this experiment?

   1. (a)To absorb carbon dioxide from the air inside the flask, thereby testing its necessity for photosynthesis.
   2. (b)To act as a catalyst that accelerates the production of chlorophyll in the enclosed leaf.
   3. (c)To absorb moisture from the air and prevent transpiration in the enclosed leaf.
   4. (d)To supply oxygen to the leaf cells so that aerobic respiration can continue without interruption.
   Show answer and step marks

   1. Correct option: (a)+1

   Answer: (a)
2. Q2Assertion and reason·1 mark
   Assertion (A): The walls of the trachea are supported by cartilaginous rings. Reason (R): Cartilaginous rings ensure that the air passage does not collapse when air is not passing through it.

   1. (a)Both Assertion (A) and Reason (R) are true and Reason (R) is the correct explanation of Assertion (A).
   2. (b)Both Assertion (A) and Reason (R) are true but Reason (R) is not the correct explanation of Assertion (A).
   3. (c)Assertion (A) is true but Reason (R) is false.
   4. (d)Assertion (A) is false but Reason (R) is true.
   Show answer and step marks

   1. Correct option: (a) Both Assertion (A) and Reason (R) are true and Reason (R) is the correct explanation of Assertion (A). Cartilage rings provide structural support to prevent tracheal collapse during pressure changes, confirming both statements and their relation.+1

   Answer: (a)
3. Q3Multiple choice·1 mark
   What structural adaptation prevents the backflow of blood from the ventricles into the atria during ventricular systole in the human heart?

   1. (a)Semilunar valves
   2. (b)Purkinje fibers
   3. (c)Aortas
   4. (d)Atrioventricular (bicuspid and tricuspid) valves
   Show answer and step marks

   1. Correct option: (d)+1

   Answer: (d)
4. Q4Assertion and reason·1 mark
   Assertion (A): Fungi like bread moulds and yeasts break down food material outside the body and then absorb it. Reason (R): These organisms are saprophytes that secrete digestive enzymes externally onto organic matter.

   1. (a)Both Assertion (A) and Reason (R) are true and Reason (R) is the correct explanation of Assertion (A).
   2. (b)Both Assertion (A) and Reason (R) are true but Reason (R) is not the correct explanation of Assertion (A).
   3. (c)Assertion (A) is true but Reason (R) is false.
   4. (d)Assertion (A) is false but Reason (R) is true.
   Show answer and step marks

   1. Correct option: (a) Both Assertion (A) and Reason (R) are true and Reason (R) is the correct explanation of Assertion (A).+1

   Answer: (a)
5. Q5Short answer·2 marks
   What is the basic structural and functional unit of the human kidney? Name its two main components.
   Show answer and step marks

   1. The basic structural and functional unit of the kidney is the nephron.+1
   2. First component: Bowman's capsule with the glomerulus inside it (the renal or Malpighian corpuscle); accept glomerulus or Bowman's capsule.+0.5
   3. Second component: the renal tubule.+0.5

   Answer: Nephron; its two main components are the renal corpuscle (glomerulus in Bowman's capsule) and the renal tubule.
6. Q6Long answer·5 marks
   Plants lack specialized excretory organs and utilize various strategies to dispose of metabolic wastes. Answer the following: (a) How do plants manage gaseous wastes generated during respiration and photosynthesis? (b) Explain how waste products are stored and eliminated through plant parts like leaves and bark. (c) Describe the mechanisms by which plants get rid of excess water and wastes into the surrounding soil.
   Show answer and step marks

   1. (a) The gaseous wastes are oxygen (from photosynthesis) and carbon dioxide (from respiration).+0.5
   2. (a) They diffuse out through the stomata in leaves (and lenticels in stems).+0.5
   3. (b) Many wastes are stored in cellular vacuoles.+0.5
   4. (b) Wastes are stored in leaves, which eventually fall off.+0.5
   5. (b) Wastes such as resins and gums are stored in old xylem.+0.5
   6. (b) Wastes in the bark are removed when the bark peels off.+0.5
   7. (c) Excess water is removed mainly by transpiration through the stomata (and sometimes as droplets by guttation).+1
   8. (c) Some waste substances are excreted directly into the surrounding soil through the roots.+1

   Answer: (a) Oxygen and carbon dioxide diffuse out through stomata (and lenticels). (b) Wastes are stored in vacuoles, in leaves that fall off, and as resins and gums in old xylem; bark wastes are lost when the bark peels. (c) Excess water is lost by transpiration; some wastes are excreted into the soil through the roots.

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