Class 10 Science Chapter 5 Case Based Questions - Life Processes

The given diagram represents the structure of a human excretory system. Study the diagram and answer the questions.

Question 1: 
Which of these is the structural and functional unit of part 2?
(a) Alveoli 
(b) Nephron 
(c) Neuron 
(d) None of these

Correct Answer is Option (b)
A nephron is the basic functional unit of kidneys that consists of a glomerulus and its associated tubules through which the glomerular filtrate passes before it emerges as urine. They are the microscopic structure composed of a renal corpuscle and a renal tubule.

Question 2:
Choose the correct path of urine in our body:
(a) kidney → ureter → urethra → urinary bladder
(b) kidney → urinary bladder → urethra → ureter
(c) kidney → ureters → urinary bladder → urethra
(d) urinary bladder → kidney → ureter → urethra

Correct Answer is Option (c)
Kidneys are the paired organs where urine formation takes place. Small muscular tube, called as ureter, extend from kidneys and carries urine to urinary bladder. The urethra is a small tube that extends from the urinary bladder to an external opening.

Read the given passage and answer the questions from.
Oxygen-rich blood from the lungs comes to the thin-walled upper chamber of the heart on the left. The left upper chamber (A) then relaxes. It then contracts and the blood is allowed to enter the next chamber (B), as it expands. When the muscular left lower chamber of heart contracts the blood is pumped out to the body via aorta. Deoxygenated blood reaches from the body to the upper chamber on the right side of heart (C) and it expands. As this part contracts, the corresponding lower chamber (D) dilates. This transfers the blood to right ventricle, which in turn pumps it to the lungs for oxygenated.
Question 3:
Which of these correctly represents the label A, B, C and D in the above passage?
(a) A - Left atrium, B- Left Ventricle, C- Right atrium, D- Right ventricle
(b) A - Right ventricle, B- Left atrium, C- Left Ventricle, D- Right atrium
(c) A- Right atrium, B- Right ventricle, C- Left atrium, D- Left ventricle
(d) A- Left ventricle, B- Right atrium, C- Right ventricle, D- Left atrium

Correct Answer is Option (a)
A- Left atrium, B- Left Ventricle, C- Right atrium, D- Right ventricle

Question 4:
What is the correct route of blood in a human? 
(a) A → B → Lungs → C → D
(b) A → B → D → C → Lungs
(c) C → D → B → A → Lungs
(d) C → D → Lung → A → B

Correct Answer is Option (d)
C (Right atrium) → D (Right ventricle) → Lungs → A (Left atrium) → B (Left ventricle).

Question 5:
What prevents backflow of blood inside the heart during contraction?  
(a) Valves in heart
(b) Thick muscular walls of ventricles
(c) Thin walls of atria
(d) All of the above

Correct Answer is Option (a)
False. Valves prevent the back flow of blood inside the heart during contraction of heart chambers (atria or ventricles).

Read the passage and answer the questions.
Some experiments were carried out using Croton sp. plants to understand the process of photosynthesis. It was observed that the leaves of the plant exposed to light for longer duration accumulated more starch. However, due to presence of pre-formed starch in the leaves, it was difficult to find the net productivity on a fixed exposure to light source. Therefore, it was necessary to obtain starch free leaves in the plant before starting the experiment.
Question 6:
Which of the following would help obtain starch free leaves in the plant? 
(a) Expose the leaves to blue light for 48 hours before starting the experiment.
(b) Keep the plant in dark for about 48 hours before starting the experiment.
(c) Remove starch from the leaves by exosmosis, 48 hours before starting the experiment.
(d) Keep the leaves to red light for 48 hours before starting the experiment.

Correct Answer is Option (b)
The starch free leaves can be obtained by keeping the plant in dark, so that already present starch is utilized in 48 hrs.

Question 7:
After a period of illumination, the leaves were boiled in alcohol to make them colourless. Which of the following could be used to test the end product stored in the leaves? 
(a) Cobalt chloride paper
(b) Litmus paper
(c) Iodine solution
(d) Copper sulphate solution

Correct Answer is Option (c)
Starch presence can be tested by adding iodine solution which gives bluish black colour of starch – iodine mixture.

Question 8:
Some of the starch free leaves were coated with wax on both the surfaces. The plant was maintained under normal environmental conditions. At the end of the experiment, the wax coated leaves are likely to show _____. 
(a) Accumulation of more water.
(b) Wilting of the wax coated leaves.
(c) Increase in sucrose accumulation.
(d) Decrease in number of chloroplasts

Correct Answer is Option (b)
Wilting occurs due to wax blocks the transpiration so water transportation inhibits.

Question 9:
During the morning hours, using a fine blade, an incision was made to the leaves such that the phloem tissue was cut open. Analysis of the liquid oozing out was found to contain high amount of: 
(a) Xylose
(b) Ribose
(c) Sucrose
(d) Galactose

Correct Answer is Option (c)
The transport of glucose, occurs in the form of sucrose, in phloem therefore, when cell sap oozes out, liquid contains sucrose.