Tag: the respiratory system

Questions Related to the respiratory system

Lungs lie in the thoracic cavity separated by ............ from the abdominal cavity.

  1. Septum

  2. Diaphragm

  3. Thoracic cage

  4. Ribs


Correct Option: B
Explanation:

The diaphragm separates the thoracic cavity, containing the heart and lungs, from the abdominal cavity and performs an important function in respiration. As, the diaphragm contracts, the volume of the thoracic cavity increases and air is drawn into the lungs.  It is a dome-shaped sheet of muscle that is inserted into the lower ribs. 

Cluster of air sacs in lungs are called

  1. Alveolus

  2. Bronchi

  3. Braonchioles

  4. Air spaces


Correct Option: A

Pick the correct statement.

  1. The contraction of internal intercostal muscles lifts up the ribs and sternum.

  2. The thoracic cavity is anatomically an air tight chamber.

  3. Healthy man can inspire approximately $500$ ml of air per minute.

  4. During expiration, the intrapulmonary pressure is slightly below the surrounding atmospheric pressure.


Correct Option: B
Explanation:

The thoracic chamber is formed dorsally by the vertebral column, ventrally by the sternum, laterally by ribs and lower side by the dome-shaped diaphragm, it is an air-tight chamber.

So, the correct option is 'The thoracic cavity is anatomically an airtight chamber.'

Which one of the following statements is incorrect?

  1. The principle of countercurrent flow facilitates efficient respiration m gilis of fishes.

  2. The residual air in lungs slightly decreases the efficiency of respiration in mammals.

  3. The presence of non-respiratory air sacs, increases the efficiency of respiration in birds.

  4. In insects, circulating body fluids serve to distribute oxygen to tissues.


Correct Option: D
Explanation:

In insects, blood (haemolymph) does not contain an oxygen-carrying pigment. Hence it does not help in respiration. Instead, insects have spiracles and tracheae that carry $O _{2}$ to different tissues.

Anaerobic process that takes place after glycolysis is called as

  1. TCA

  2. Calvin cycle

  3. Krebs cycle

  4. Fermentation


Correct Option: D
Explanation:

Anaerobic process after glycolysis is called as fermentation. Fermentation could be defined as a metabolic process, that converts sugar into acids, gases and alcohol. It occurs in yeast and bacteria, but also in oxygen-starved muscle cells, as in the case of lactic acid fermentation.

What is common in common pathway of aerobic respiration

  1. Glycolysis in both aerobic and anaerobic respiration

  2. Krebs cycle common with HMP

  3. Terminal oxidation in both aerobic and anaerobic respiration

  4. Krebs cycle in both aerobic and anaerobic respiration


Correct Option: A
Explanation:

Aerobic respiration is the oxidative breakdown of respiratory substrates with the help of atmospheric oxygen. It takes place in three steps: Glycolysis, Kreb's cycle and electron transport chain. Anaerobic respiration is the breakdown of respiratory substrates in the absence of atmospheric oxygen. The first step of aerobic respiration as well as anaerobic respiration is same and takes place in the cytoplasm of cells. Glycolysis is the common pathway of both the processes in which glucose is broken down anaerobically into two molecules of pyruvic acid. 

Thus, the correct answer is option A. 

Read the following four statements (A-D)
A) In fermentation, less than seven percent of the energy in glucose is released
B) Glycolysis occurs in the cytoplasm of the cell and is present only in anaerobic organisms
C) The number of ATP molecules synthesized in ETS depends on the nature of the electron donor
D) In glycolysis, glucose undergoes coin, complete oxidation to form two molecules pyruvic acid
How Many of the above statements are correct?

  1. 1

  2. 2

  3. 3

  4. 4


Correct Option: B
Explanation:

A) In fermentation, less than seven percent of the energy in glucose is released because only two ATPs are produced at this stage compared to the total number of 32 ATPs in aerobic respiration. The percentage of energy produced is thus (2/32)*100=6.25%.


C) When electrons are transferred from one carrier to next carrier via complexes I to IV in ETS, they are coupled to the production of proton motive force by transport of protons from the lumen to the inner mitochondrial membrane. The number of protons displaced will ultimately determine the number of ATP molecules that will be produced, i.e. for NADH it will be 2.5 and for FADH2 it will be 1.5.


So, the correct option is '2'.

If one triose phosphate completely oxidized inside the prokaryotic cell, then the net gain of ATP of energy is equal to

  1. $5$ ATP

  2. $4$ ATP

  3. $20$ ATP

  4. $19$ ATP


Correct Option: C
Explanation:

If one triose phosphate completely oxidized inside the prokaryotic cell, then the net gain of ATP of energy is equal to the summation of the ATPs produced at different steps. In the glycolysis step 2 ATP and 1 NADH will be produced followed by 1 NADH in the gateway reaction and 1 GTP, 3 NADH and 1 FADH2 in the TCA cycle. This will add up to 20 ATPs.


So, the correct option is '20 ATP'.

The total number of ATP's formed when one molecule of glucose is oxidized to $CO _2$ to $H _2 O $ is

  1. 32

  2. 38

  3. 42

  4. 40


Correct Option: B
Explanation:
One molecule of the glucose that enters in the glycolysis produces 2 molecules pyruvate and 2 molecules of NADH$ _{2}$ and 2 ATP.  2 molecules of pyruvate will form 2 molecules of Acetyl Co-A and this will release 2 NADH$ _{2}$. These 2 Acetyl Co-A will enter into Kreb's cycle and will release 6NADH$ _{2}$, 2FADH$ _{2}$ and 2ATP.
so, the total gain before the ETC (electron transport chain) comes out to be  10NADH$ _{2}$, 2FADH$ _{2}$ and 4ATP.
Now, during the electron transport chain, 
10NADH$ _{2}$ will give 10 X 3=30 ATP
2FADH$ _{2}$ will give 2 X 2= 4 ATP
So, 34 ATP from ETC and 4 ATP from Kreb's cycle will be 38 ATP.
Hence, the correct answer is '38'

Total $ATP$ through aerobic EMP pathway can be

  1. $6$

  2. $10$

  3. $2$

  4. $8$


Correct Option: D
Explanation:

Glycolysis is also known as 'EMP pathway'. It was discovered by three scientist Gustav Embden, Otto Meyerhof, and Jakub Karol Parnas. That's why glycolysis is also known as the EMP pathway. In the EMP pathway, total 8 ATP are produced.

So, the correct answer is '8 ATP'.