NEET Biology: Respiratory System questions with solutions

Q1. Inspiration occurs when

1. Pressure inside lungs is lower than atmospheric pressure
2. Pressure inside lungs is higher than atmospheric pressure
3. Pressure inside lungs is same as atmospheric pressure
4. Pressure has no effect

Answer: Pressure inside lungs is lower than atmospheric pressure

Inspiration happens when the pressure inside the lungs becomes lower than atmospheric pressure, creating a gradient that drives air into the lungs. Air always flows from higher pressure to lower pressure until pressures begin to equalize.

Q2. The number of time a person breathes in a minute is known as This question has multiple correct options

1. Respiration rate
2. Breathing rate
3. combustion rate
4. None of the above

Answer: Breathing rate

The number of breaths a person takes in one minute is commonly called the breathing rate. It is also sometimes referred to as respiration rate, but among the given options the correct choice is Breathing rate.

Q3. Tidal volume of air in a normal healthy man during inspiration is about

1. 300-400ml
2. 500-700ml
3. \( 900-1000 \mathrm{ml} \)
4. 100-250ml

Answer: 500-700ml

Tidal volume is the amount of air moved in or out during a normal quiet breath. In a healthy adult, this is about 500 mL, which matches the 500–700 mL range best.

Q4. How much amount of volume of air is in lungs as FRC?

1. \( 1500 \mathrm{ml} \) to \( 1600 \mathrm{ml} \)
2. 2100 m| to 2500 m1
3. 2500 \( \mathrm{ml} \) । to \( 3000 \mathrm{ml} \)
4. 1600 \( \mathrm{ml} \) to \( 2100 \mathrm{ml} \)

Answer: 1600 \( \mathrm{ml} \) to \( 2100 \mathrm{ml} \)

Functional residual capacity (FRC) is the volume remaining in the lungs at the end of a normal expiration. In adults, this is typically about 1600 to 2100 mL, which matches the correct option.

Q5. Arrange the following terms regarding process of respiration in chronological order of its decreasing volume of air I. Expiratory reserve volume II. Vital capacity III. Tidal volume IV. Residual volume

1. \( I I \rightarrow I V \rightarrow I \rightarrow I I I \)
2. \( I I \rightarrow I V \rightarrow I I I \rightarrow I \)
3. \( I \rightarrow I V \rightarrow I I I \rightarrow I I \)
4. \( I V \rightarrow I \rightarrow I I I \rightarrow I \)

Answer: \( I V \rightarrow I \rightarrow I I I \rightarrow I \)

Residual volume is the smallest because it is the air left after forceful expiration. Expiratory reserve volume is next, followed by tidal volume, while vital capacity is the largest among these because it combines several volumes.

Q6. Total lung capacity is

1. 1 llit
2. 3 litt
3. 6 lit
4. 8 litt

Answer: 6 lit

Total lung capacity is the sum of all lung volumes after maximal inspiration, and in a healthy adult it is about 6 liters. That makes 6 lit the best choice.

Q7. What percentage of \( C O_{2} \) flows in blood in form of bicarbonates?

1. 7\%
2. 23\%
3. 50\%
4. 70\%

Answer: 70\%

Carbon dioxide is transported in blood mainly after conversion to bicarbonate ions (HCO3−) inside red blood cells. This is the dominant form, accounting for about 70% of CO2 transport.