Question

Which statement is wrong for anaerobic respiration?
A. ${O_2}$ is given out
B. $C{O_2}$ is given out
C. $C{O_2}$ is taken in
D. ${O_2}$ is taken in

Answer 1

Hint: Respiration is the process by which cells produce energy by utilizing a fuel molecule. Generally, glucose serves as the fuel molecule and energy is produced in the form of ATP. Respiration that uses oxygen as an electron acceptor is called aerobic. While if it uses sulphate, fumarate, sulphur or nitrate as the electron acceptors the process is said to be anaerobic.

Complete answer:
Anaerobic respiration occurs in organisms that dwell in an environment where oxygen level is low and by certain cells of higher animals in an oxygen deficient state.
The process involves extraction of an electron from a fuel molecule. The electron is then passed through an electron transport chain which results in ATP production. The electron acceptor in this process is either sulphate, or nitrate or sulphur. This is in contrast to the aerobic form of respiration where oxygen acts as the electron acceptor.
Anaerobic respiration is of two types: lactic acid fermentation and alcoholic fermentation. In both these processes the initial phase of glycolysis takes place. The two molecules of pyruvate produced as a result of glycolysis are then converted to lactic acid in lactic acid fermentation and to ethanol in alcoholic fermentation.
Lactic acid fermentation occurs in human beings. During intense exercise, the muscle cells spend more oxygen to produce energy than they are able to take in. This creates an anaerobic environment in the muscles. Thus, the rate of pyruvate formation exceeds its metabolism. This causes the muscle cells to undergo lactic acid fermentation. The lactic acid accumulation in muscles is a major cause of muscle cramps associated with intense forms of exercise.
Alcoholic fermentation does not take place in humans.
Therefore, we can conclude that $C{O_2}$ is not given out during anaerobic respiration in animals.

Hence, the correct answer is option (B).

Note: Anaerobic respiration occurs in an oxygen deficient environment. The process typically uses nitrate or sulphur as the electron acceptor. The process is less efficient than the aerobic process. Anaerobic respiration takes place in muscle cells of animals. Yeast can also undergo the process of anaerobic respiration through alcoholic fermentation.