Question

Which statement explains the significance of myoglobin muscle tissue?
A. Myoglobin can associate with oxygen in conditions of high carbon dioxide tension.
B. Myoglobin can dissociate from oxygen most readily under aerobic conditions.
C. Myoglobin acts as an oxygen store delaying the onset of anaerobic conditions.
D. Myoglobin acts as a buffer to hydrogen ions produced during anaerobic respiration.

Answer 1

Hint: Myoglobin is a protein, which is present in skeletal muscular cells of mammals and vertebrates. It is abbreviated as Mb or MB. Myoglobin and hemoglobin are distantly related. It is a low molecular weight component, which is an oxygen binding heme protein. It contains a heme prosthetic group. It binds with oxygen molecules reversibly. Its molecular weight is $$16700$$.

Complete answer
Option A Myoglobin can associate with oxygen in conditions of high carbon dioxide tension: During high carbon dioxide tension, myoglobin disassociates with oxygen, so that oxygen concentration in the cells can compete and outnumber carbon dioxide concentration.
Option A is not correct.
Option B Myoglobin can dissociate from oxygen most readily under aerobic conditions: Myoglobin binds oxygen strongly and it won’t release oxygen readily.
Hence, Option B is not correct.
Option C Myoglobin acts as an oxygen store delaying the onset of anaerobic conditions: Myoglobin acts as a buffer of oxygen concentration inside cells. Also, in muscle, it is an oxygen reservoir. When the levels of oxygen decreases, myoglobin will release the stored oxygen, which will keep the muscles working.
So, Option C is correct.
Option D Myoglobin acts as a buffer to hydrogen ions produced during anaerobic respiration: Myoglobin has a binding affinity to oxygen, but not hydrogen. So binding does not happen.
Option D is not correct.

Therefore, Option C. is the correct answer.

Note:
Myoglobin has $$154$$ amino acids, made of a single polypeptide chain. Supply of oxygen to the muscle is its primary function. Diving mammals have higher concentrations of myoglobin. It also helps in mitochondrial respiration by nitric oxide removal. It also removes reactive oxygen species during high energy demands. It aids in increasing oxygen’s diffusion rate.