Science (English Medium) Class 11 - CBSE Question Bank Solutions

Correct the statement given below by the right option shown in the bracket against them.

The faeces in the rectum initiate a reflex causing an urge for its removal. (neural/hormonal)

Discuss mechanisms of absorption.

Name the primary site of exchange of gases in our body?

Compared to O₂, diffusion rate of CO₂ through the diffusion membrane per unit difference in partial pressure is much higher. Explain.

Which of the following statements is correct?

Which one of the following is also known as antidiuretic hormone?

The following abbreviations are used in the context of excretory functions, what do they stand for?

ANF

The following abbreviations are used in the context of excretory functions, what do they stand for?

ADH

What is the role played by Renin-Angiotensin in the regulation of kidney function?

Comment upon the hormonal regulation of selective reabsorption.

Exchange of calcium between bone and extracellular fluid takes place under the influence of certain hormones. What will happen if more of Ca⁺⁺ is in extracellular fluid?

Exchange of calcium between bone and extracellular fluid takes place under the influence of certain hormones. What will happen if very less amount of Ca⁺⁺ is in the extracellular fluid?

Rahul exercises regularly by visiting a gymnasium. Of late he is gaining weight. What could be the reason? Choose the correct answer and elaborate.

Radha was running on a treadmill at a great speed for 15 minutes continuously. She stopped the treadmill and abruptly came out. For the next few minutes, she was breathing heavily/fast. Answer the following questions.

What happened to her muscles when she did strenuously exercised?

Radha was running on a treadmill at a great speed for 15 minutes continuously. She stopped the treadmill and abruptly came out. For the next few minutes, she was breathing heavily/fast. Answer the following questions.

How did her breathing rate change?

What is the source of energy for muscle contraction?

Calcium ion concentration in blood affects muscle contraction. Does it lead to tetany in certain cases? How will you correlate fluctuation in blood calcium with tetany?

Explain sliding filament theory of muscle contraction with neat sketches.

Discuss the role of Ca²⁺ ions in muscle contraction. Draw neat sketches to illustrate your answer.

How does a muscle shorten during its contraction and return to its original form during relaxation?