Biology

Respiration and Gas Exchange

958 Questions

Access a targeted set of questions on respiration and gas exchange for competitive exams. Topics include lung volumes, the mechanism of breathing, and respiratory anatomy. Understanding these physiological processes is essential for scoring well.

Lung volumes and capacitiesBreathing mechanismsRespiratory anatomyGas exchange processes

Respiration and Gas Exchange Questions

Multiple choice

Which of the following takes place during the process of exhalation?

  1. Rib cage contracts

  2. Lung expands

  3. Diaphragm lowers down

  4. Oxygen moves out

  5. All of these
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

 When the diaphragm moves up, the ribcage contracts. This leads to contraction of the lungs. As a result, the air moves out of the lungs. This process is called expiration or exhalation.

Multiple choice

What is the vital capacity of lungs of an average human?

  1. 3000 - 4500 ml

  2. 4200 - 5500 ml

  3. 1500 - 1800 ml

  4. 500 - 1000 ml
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Vital capacity is the maximum volume of air a person can expel from lungs after maximal inhalation (VC = TV + IRV + ERV). For an average adult human, this ranges from 3000-4500 ml. Option B's lower bound is too high, while options C and D represent tidal volume and residual volume respectively, which are much smaller. Option A has a typo character but the range is correct.

Multiple choice

Which of the following prevents collapsing of trachea?

  1. Muscles

  2. Diaphragm

  3. Ribs

  4. Cartilaginous rings

Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

The trachea is prevented from collapsing by C-shaped cartilaginous rings made of hyaline cartilage. These rings provide structural support while allowing flexibility for esophagus expansion behind the trachea (the open part of C faces posteriorly). Muscles and diaphragm are involved in breathing mechanics but don't support the trachea structure itself. Ribs protect the lungs but not the trachea.

Multiple choice

What happens if the thoracic wall is punctured?

  1. The lungs get inflated

  2. The man dies as the lungs get collapsed

  3. The breathing rate decreases

  4. The breathing rate increases
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

If the thoracic wall is punctured, the man dies as the lungs get punctured.

Multiple choice

What happens to the diaphragm at the time of inspiration?

  1. expands

  2. contracts

  3. Relaxes

  4. Remains unchanged
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

During inspiration (inhalation), the diaphragm contracts and flattens, increasing the volume of the thoracic cavity. This creates negative pressure that draws air into the lungs. During expiration, the diaphragm relaxes and returns to its dome shape. Option A is vague (expands is not the precise term - contracts/flatten is more accurate).

Multiple choice

Exchange of gases in lung alveoli occurs through

  1. active transport

  2. osmosis

  3. simple diffusion

  4. passive transport

Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

Gas exchange in alveoli occurs by simple diffusion - oxygen moves from alveolar air (higher PO2) into blood (lower PO2), and CO2 moves from blood (higher PCO2) into alveoli (lower PCO2). This is passive movement down concentration gradients without energy expenditure. Osmosis is water movement, active transport requires energy, and passive transport is a broader category.

Multiple choice

Why the air that we exhale is warmed?

  1. As it passes through nasal cavities.

  2. As it passes through trachea.

  3. As it passes through alveoli.

  4. As it passes through bronchial arteries.
Reveal answer Fill a bubble to check yourself
A Correct answer
Multiple choice

Why does a man at rest breathe at a slower rate as compared to a man running?

  1. The organs of a man at rest are also at rest. Hence, breathing is also slow.

  2. As he is resting, he is not aware of breathing.

  3. A man at rest has low energy as compared to a man who is running and hence, he cannot exhale and inhale quickly.

  4. A man, who is sleeping, does not require more of oxygen. Hence, he breathes at a normal rate.

  5. None of these
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

Yes, it is correct. The rate of breathing increases when we do strenuous physical work like running. But when we are at rest, our breathing is normal.

Multiple choice

Which of the following statements regarding exhalation process in human beings is correct?

  1. Air moves out, rib cage moves out and diaphragm moves down.

  2. Air moves out, rib cage moves in and diaphragm moves up.

  3. Air moves in, rib cage moves out and diaphragm moves down.

  4. Air moves in, rib cage moves in and diaphragm moves up.

  5. None of these
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

Yes, it is correct. When the diaphragm moves up, the rib cage moves in and air is exhaled.

Multiple choice

Breathing rate can be calculated by

  1. counting the number of inhales in a minute

  2. counting the number of exhales in a minute

  3. counting the number of inhales and exhales in a minute

  4. the amount of glucose oxidised per minute

  5. None of these
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

Yes, it is correct. The number of times a person inhales and exhales in a minute is the breathing rate. A complete breath is inhaling and exhaling once.

Multiple choice

Which of the following statements regarding respiration is true?

  1. Water is used during respiration.

  2. Water is released during aerobic respiration.

  3. Water is released when respiration happens in human muscles.

  4. Water is released when microbes respire.

  5. None of these
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

Yes, it is correct. In aerobic respiration, carbon dioxide and water are the end products.

Multiple choice

Fill in the numbered blank (ii).

Directions: Choose the best option to fill in the blank.

Yawning is an involuntary ______(i)______ in which your mouth opens up wide and you inhale deeply, followed by _____(ii)_____. When you say involuntary, this means that you have no _____(iii)_____ over this action much like other reflexes such as blinking or sneezing. Yawns are not _____(iv)______ only to human beings as all other animals do this. Despite a lot of _____(v)_____, we still know little about the causes of yawning.

  1. breathing

  2. exhaling

  3. resting

  4. closing
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

Exhale means to blow forth or breathe out. 'Breathing' cannot be the answer as it should be followed by 'out' to make sense here.