Lec. 15 - Cellular Respiration

Question 1

Describe what occurs after glycolysis, when oxygen is not present.

Answer 1

In the absence of oxygen, cells fermentate to regenerate NAD+ from the excess NADH produced during glycolysis.

Question 2

Explain the difference between pyruvate oxidation and fermentation.

Answer 2

Pyruvate oxidation occurs in the mitochondrial matrix of eukaryotic cells, and its outcome is the formation of acetyl CoA. Fermentation occurs in the cytoplasm and its outcome is to regenerate NAD+ from the excess NADH produced during glycolysis.

Question 3

Compare the citric acid cycle and the electron transport chain and the inputs and outputs of each.

Answer 3

They are interconnected processes involved in cellular respiration. the Krebs Cycle occurs in the mitochondrial matrix of eukaryotes, and it’s inputs are acetyl CoA and oxaloacetate. Its outputs are ATP, NADH and FADH2, and carbon dioxide. ETC is located on the inner mitochondrial membrane. Inputs are NADH and FADH2 and oxygen. Outputs are ATP and water.

Question 4

Describe the process of chemiosmosis, and the importance of the proton gradient in ATP generation.

Answer 4

Chemiosmosis is a process that occurs during oxidative phosphorylation in cellular respiration. The pumping of protons creates a higher concentration of protons in the inter-membrane space, which establishes the proton gradient.

Question 5

Explain the role of NAD+/NADH in cellular respiration.

Answer 5

NAD+ functions as an electron acceptor during the oxidation of organic molecules, while NADH carries high energy electrons to the ETC for ATP production in oxidative phosphorylation.