Question

level 2 q1 in glycolysis, glucose is broken down into two molecules of what? a. pyruvic acid b. fructose c. acetyl-coa d. lactate level 2 q2 what is the gain of atp at the end of the electron transport chain? a. 1 atp b. 38 atp c. 35 atp d. 2 atp level 2 q3 which of the following statements is false? a. glycolysis can occur with or without oxygen b. glycolysis occurs in the mitochondria. c. glycolysis produces 2 atp, and 2 pyruvic acids. d. glycolysis is the first step in both aerobic and anaerobic respiration level 2 q4 before the krebs cycle, pyruvate must be broken down into what molecule? a. pyruvate coa b. coenzyme a c. acetyl coa d. nadh

Explanation:

Q1

Glycolysis is the first step of cellular respiration where glucose (a 6 - carbon molecule) is broken down into two molecules of pyruvic acid (a 3 - carbon molecule). Fructose is a different sugar, Acetyl - CoA is formed after pyruvate is processed before the Krebs cycle, and lactate is a product of anaerobic respiration (fermentation) of pyruvate in some organisms, not the direct product of glycolysis.

The Electron Transport Chain (ETC) is the final stage of aerobic respiration. In the ETC, the majority of ATP is produced. The total gain of ATP at the end of the ETC (along with oxidative phosphorylation) is around 32 - 34 ATP, but when considering the overall aerobic respiration (glycolysis, Krebs cycle, ETC), the total can be around 36 - 38 ATP. However, the gain specifically at the ETC is a significant portion, and among the options, 38 ATP is the value associated with the total aerobic respiration (including ETC) and is the most appropriate here as the other options (1, 35, 2) are incorrect. 2 ATP is the gain from glycolysis, 1 is too low, and 35 is not the typical value for ETC gain.

• Option A: Glycolysis is an anaerobic process in itself but can also occur in the presence of oxygen (as it is the first step of aerobic respiration), so it can occur with or without oxygen. This statement is true.
• Option B: Glycolysis occurs in the cytoplasm of the cell, not in the mitochondria. The mitochondria are the site of the Krebs cycle and the Electron Transport Chain. So this statement is false.
• Option C: Glycolysis breaks down one glucose molecule into two pyruvic acid molecules and produces a net gain of 2 ATP. This statement is true.
• Option D: Glycolysis is indeed the first step in both aerobic (which then proceeds to Krebs cycle and ETC) and anaerobic (which proceeds to fermentation) respiration. This statement is true.

Answer:

A. Pyruvic acid

Q2