Question

1) which is a role of cellular respiration in cycling materials between the atmosphere and biosphere?

A. it transfers carbon to the atmosphere as carbon dioxide
B. it transfers carbon to the biosphere as glucose
C. it transfers oxygen gas to the atmosphere
D. it transfers water from the atmosphere to the biosphere

2) compared to aerobic respiration the process of fermentation provides which of these advantages to the cell?
A. fermentation can occur without glucose
B. fermentation can occur without producing wastes
C. fermentation produces more ATP per glucose molecule
D. fermentation can occur without oxygen

Answer 1

1. The correct answer is option (A) it transfers carbon to the atmosphere as carbon dioxide.

Cellular respiration refers to the set of metabolic reactions and processes that occur in the cells of the organisms, involving the oxidation of organic compounds. It is a process where in, the nutrients are catabolized in presence of oxygen, releasing carbon dioxide, water and energy. It is a part of the carbon cycle. Carbon cycle includes the processes by which the carbon compounds are inter converted in the environment. One such step in the carbon cycle is the process of respiration in plants and animals releases carbon dioxide back into the atmosphere.

2. The correct answer is option (D) fermentation can occur without oxygen.

Aerobic respiration is a process in which the glucose is broken down into carbon dioxide, water and energy in presence of oxygen. Each molecule of glucose produces 38 ATPs. Fermentation refers to the breakdown of sugars in the absence of oxygen. During fermentation, pyruvate which is a product of glycolysis is converted into ethanol, releasing carbon dioxide and energy (2 ATP per molecule) by yeast and certain bacteria.

Pyruvate → ethanol + carbon dioxide + energy.

Answer 2

1) The correct answer would be A. it transfers carbon to the atmosphere as carbon dioxide.

Cellular respiration refers to the set of biochemical reactions take place in a cell in order to convert the energy of glucose into adenosine triphosphate (ATP).

The carbon dioxide is released as the byproduct of the process.

C₆H₁₂O₆ + 6O₂ → 6CO₂ + 6H₂O + ATP

2) The correct answer would be D. fermentation can occur without oxygen.

Fermentation is the process which occurs in oxygen is either absent or present in very less amount.

Thus, it enables the cell to survive when oxygen is not available.

For example, in humans, the muscle cells switch to lactic acid fermentation when oxygen supply is decreased during intense exercise.

It produces very less amount of ATP as compared to the aerobic respiration.