Question

Given below are two statements:
Statement (I) : A shift to right in the Hemoglobin- Oxygen dissociation curve (ODC) indicates that Hemoglobin has a decreased affinity for oxygen.
Statement (II) : Principal gas (by percentage) produced in the rumen after fermentation of dietary substrate is \(CO_2\) and not methane.
In light of the above statements, choose the most appropriate answer from the options given below.

• A. Both Statement (I) and Statement (II) are correct.
• B. Both Statement (I) and Statement (II) are incorrect.
• C. Statement (I) is correct but Statement (II) is incorrect.
• D. Statement (I) is incorrect but Statement (II) is correct.

Hint:

To remember ODC shifts: - Shift to the Right = Release of oxygen (decreased affinity, happens in active tissues).
- Shift to the Left = Loading of oxygen (increased affinity, happens in the lungs).

Answer 1

The Correct Option is A

Step 1: Understanding the Concept:
This question covers respiratory physiology (the oxygen-hemoglobin dissociation curve) and digestive physiology (the gases produced during anaerobic fermentation in the rumen).

Step 2: Detailed Explanation:
Statement (I) describes a rightward shift in the Oxygen Dissociation Curve (ODC).
A shift to the right means that at any given partial pressure of oxygen (\(pO_2\)), hemoglobin binds less oxygen.
This indicates a decreased affinity of hemoglobin for oxygen.
This shift is caused by factors like increased temperature, higher \(CO_2\) levels, lower pH (the Bohr effect), and increased 2,3-DPG.
This change is beneficial because it helps hemoglobin release oxygen more easily to active tissues.
Thus, Statement (I) is correct.
Statement (II) looks at the gases produced during rumen fermentation.
Microbial fermentation in the rumen produces large volumes of gas, which are expelled through eructation (belching).
The primary gases produced are:
- Carbon Dioxide (\(CO_2\)): Makes up \(60\%\) to \(70\%\) of the total rumen gas volume.
- Methane (\(CH_4\)): Makes up \(30\%\) to \(40\%\) of the volume.
- Other gases (nitrogen, oxygen, hydrogen, and hydrogen sulfide) are present in very small trace amounts.
Because carbon dioxide is the most abundant gas by volume, it is the principal gas produced, not methane.
Thus, Statement (II) is correct.

Step 3: Final Answer:
Both Statement (I) and Statement (II) are correct.