Cell Biology - Respiration

Question 1

first stage of respiration

Answer 1

• glucose is broken down into two molecules of pyruvate
• this releases enough energy to yield two molecules of ATP
• this takes place in the cytoplasm

Question 2

aerobic respiration

Answer 2

• in the presence of oxygen, aerobic respiration is completed in the mitochondria
• each pyruvate is broken down into carbon dioxide and water
• this releases enough energy to yield a large number of ATP molecules

Question 3

fermentation

Answer 3

• in the absence of oxygen, the process of fermentation is completed in the cytoplasm
• pyruvate is converted into lactate (in animals and bacteria)
• pyruvate is converted into ethanol and carbon dioxide (in plants and yeast)
• The breakdown of each glucose molecule via the fermentation pathway yields only the initial two ATP molecules (from the first stage)