Which statement best explains how aerobic respiration functions to cycle matter and energy within a cell?
a
Respiration converts glucose to alcohol using free electrons as energy.
b
Respiration produces glucose from carbon dioxide and releases energy in the form of free electrons.
c
Respiration uses sunlight energy to create glucose from carbon dioxide and water.
d
Respiration breaks down glucose and releases energy in the form of ATP.
d
Respiration breaks down glucose and releases energy in the form of ATP.
The correct answer is option D: Respiration breaks down glucose and releases energy in the form of ATP.
To understand why this is the correct answer, let's break it down:
Aerobic respiration is the process by which cells convert glucose into usable energy molecules called ATP (adenosine triphosphate). It occurs in the presence of oxygen and involves a series of complex biochemical reactions.
The first step is called glycolysis, which occurs in the cytoplasm of the cell. During glycolysis, glucose is broken down into two molecules of pyruvate, resulting in a small amount of ATP and NADH (nicotinamide adenine dinucleotide) being produced.
The second step is the citric acid cycle (also known as the Krebs cycle), which takes place in the mitochondria of the cell. In this cycle, the pyruvate from glycolysis is further broken down, releasing carbon dioxide and generating ATP, NADH, and FADH2 (flavin adenine dinucleotide).
The final step is oxidative phosphorylation, which also occurs in the mitochondria. This step involves the electron transport chain, where electrons from NADH and FADH2 are passed along a series of protein complexes, creating a proton gradient across the inner mitochondrial membrane. The energy released from this electron transfer is used to pump protons across the membrane, which drives the synthesis of ATP.
Overall, aerobic respiration breaks down glucose into carbon dioxide and water, releasing energy in the form of ATP.
d
Respiration breaks down glucose and releases energy in the form of ATP.