Railway Science (Biology – Respiratory System)

Total Questions: 56

1. What part of the respiratory system prevents the air-passage from collapsing? [RRC Group D 17/08/2022 (Morning)]

Correct Answer: (b) Rings of cartilage
Solution:

Rings of cartilage (C-shaped 20 rings) in the trachea protect and prevent the trachea from collapsing during the absence of air. Ribs - Protect the thoracic organs. The spine - It supports the body system for movement.
Trachea - It carries air in and out of your lungs. Other parts of the respiratory system- Nose, Throat (pharynx), Voice box (larynx), Large airways (bronchi), Small airways (bronchioles), and Lungs.

2. Which of the following statements is FALSE? [RRC Group D 17/08/2022 (Evening)]

Correct Answer: (b) In the mitochondria, acetic acid is broken down utilising oxygen.
Solution:

In the First Stage of Respiration (Anaerobic Respiration), the Glucose (C₆H₁₂O₆) is broken down into Pyruvate or Pyruvic Acid (C₃H₄O₃) during glycolysis. In the Mitochondrial Matrix, Pyruvate is converted into two-carbon acetyl groups (by removing a molecule of carbon dioxide). Fermentation is the process of the breakdown of glucose in the absence of oxygen.

3. How will the plant be affected if the rate of respiration becomes more than the rate of photosynthesis? [RRC Group D 18/08/2022 (Evening)]

Correct Answer: (a) More food will be oxidized than that produced, and plants will starve and die.
Solution:

When the rate of respiration exceeds the rate of photosynthesis, the plant will use its stored food reserves and when the food reserves will exhaust it will eventually die. Photosynthesis converts carbon dioxide and water into oxygen and glucose. Glucose is used as food by the plant and oxygen is a by-product. Cellular respiration converts oxygen and glucose into water and carbon dioxide. Photosynthesis is an anabolic process where a new molecule (glucose) is produced. Respiration is a catabolic process in which the molecule (glucose) is broken down.

4. Some features of alveoli are mentioned below. Select the INCORRECT option. [RRC Group D 22/08/2022 (Evening)]

Correct Answer: (d) Are finger-like structure
Solution:

Are finger-like structures. Alveoli - tiny-balloon-shaped compositions, thin wall, large surface area, alignment of alveoli takes place in the form of clusters all through the lungs, positioned at the terminals of the branches of the respiratory tree, permits the lungs and the blood exchange oxygen and carbon dioxide during the process of breathing in and breathing out. Bronchi - The large air passages that lead from the trachea (windpipe) to the lungs.

5. Which of the following is the common product produced during aerobic and anaerobic respiration initially in the first step? [RRC Group D 23/08/2022 (Afternoon)]

Correct Answer: (a) Pyruvate
Solution:

Pyruvate is made in the cytosol by glycolysis. There are two types of Respiration: Aerobic Respiration (presence of oxygen) and Anaerobic Respiration (absence of oxygen). Glycolysis is a common step for both aerobic and anaerobic respiration.
It takes place in the cytoplasm and is independent of the presence or absence of oxygen. Two molecules of pyruvic acid/pyruvate are formed as the end product of glycolysis. This pyruvate enters the mitochondria and participates in the aerobic phase of cellular respiration.

6. Breathing holes are found in which of the following animals? [RRC Group D 24/08/2022 (Evening)]

Correct Answer: (d) Cockroach
Solution:

Insects without backbones breathe through a system or network of tiny tubes called tracheae. Their bodies have small holes (spiracles) on their body which are connected to tracheae. All mammals, birds and reptiles breathe through lungs. Aquatic animals (Fish, octopus etc): Breathe through gills or skin. Earthworms: Breathe through skins.

7. The diagram below shows a part of the respiratory system in humans. Which option shows the correct labelling of ‘a’ and 'b' and the function of ‘b’ ? [RRC Group D 26/08/2022 (Morning)]

Correct Answer: (d) a - Bronchioles, b - Alveoli (exchange of gases)
Solution:

The respiratory tract in humans is made up of the following parts: Nostrils - A opening passage for air to enter inside the nose,
Nasal chamber - It is lined with mucous membrane to filter the air from dust and dirt, Pharynx a passage behind the nasal chamber and serves as the common passageway for both air and food,
Epiglottis - A flap-like structure that covers the glottis and prevents the entry of food into the windpipe,
Bronchi - large tubes that connect to your trachea (windpipe) and direct the air you breathe to your right and left lungs, Bronchioles - Small tubes within the lungs that bring air in for gas exchange,
Alveoli - A tiny air sacs at the end of the bronchioles, and Lungs - internal organs to facilitate gas exchange from the environment into the bloodstream.

8. Where does the aerobic breakdown of pyruvate take place in the human body? [RRC Group D 26/08/2022 (Evening)]

Correct Answer: (a) Mitochondria
Solution:

Pyruvate is broken down in two different ways: one is aerobic and takes place in the mitochondria, while the other is anaerobic and takes place in the cytoplasm. In the mitochondria, pyruvate is broken down into carbon dioxide and water. Mitochondria are similar to a furnace or a powerhouse in the cell because they make energy from fundamental components, just as furnaces and powerhouses.

9. All the statements given below regarding respiration in humans are correct except one. Identify the incorrect statement. [RRC Group D 26/08/2022 (Evening)]

(a) The ribs sink in, and the diaphragm rises upwards.
(b) The ribs rise up, and the diaphragm flattens.
(c) The thoracic cavity becomes larger.
(d) Air is taken in by the lungs.

Correct Answer: (a) a
Solution:

When we inhale air, it passes through our nostrils into the nasal cavity. From the nasal cavity, the air reaches our lungs through the windpipe. During inhalation, ribs move up and outwards and diaphragm moves down.
This movement increases space in our chest cavity and air rushes into the lungs. The lungs get filled with air. During exhalation, ribs move down and inwards, while diaphragm moves up to its former position. This reduces the size of the chest cavity and air is pushed out of the lungs.

10. Some features of a respiratory surface in animals are mentioned below. Select the INCORRECT option. [RRC Group D 02/09/2022 (Afternoon)]

Correct Answer: (b) Is very thick
Solution:

Respiratory Surface - Area or space where the gas exchanges take place. It should have a larger surface-to-volume ratio, moist inner surface, and thin wall in contact with blood capillaries. External gills, Internal gills, lungs, and the insect tracheae all can function as respiratory surfaces.