Cellular Respiration Study Guide

These flashcards cover key concepts and processes involved in cellular respiration, glycolysis, fermentation, and regulatory mechanisms.

What is the main goal of glycolysis?

To break down one glucose molecule into two pyruvates.

Where does glycolysis occur?

In the cytoplasm of all living cells.

What is the energy yield from glycolysis?

Uses 2 ATP, produces 4 ATP and 2 NADH, resulting in a net gain of 2 ATP and 2 NADH.

Is glycolysis an aerobic or anaerobic process?

Glycolysis is anaerobic and does not require oxygen.

What is the purpose of fermentation?

To regenerate NAD⁺ by reducing pyruvate when oxygen is not available.

Where does fermentation occur?

In the cytoplasm of cells.

Does fermentation produce additional ATP in the absence of oxygen?

No, fermentation does not produce additional ATP; it relies on ATP from glycolysis.

What is the byproduct of lactic acid fermentation?

Lactic acid, which can cause muscle discomfort.

What occurs during the first step of lactic acid fermentation?

Glycolysis breaks glucose into 2 pyruvate molecules.

What is the outcome of alcohol fermentation?

Regeneration of NAD⁺ and production of ethanol and CO₂.

What is the unique step in alcohol fermentation compared to lactic acid fermentation?

Pyruvate decarboxylation, where pyruvate loses a carbon as CO₂.

What are the real-world applications of yeast alcohol fermentation?

Beer and bread production.

How do cells regulate respiration based on energy needs?

By adjusting enzyme activity in glycolysis and the Krebs cycle.

What role does insulin play in regulating glucose entry into cells?

Insulin signals GLUT4 vesicles to fuse with the membrane, allowing glucose entry.

What are the three key regulatory points in glycolysis?

Hexokinase, Phosphofructokinase (PFK), and Pyruvate Kinase.

How does hexokinase regulate glucose breakdown?

It slows down when glucose-6-phosphate (G6P) levels are high.

What does phosphofructokinase do regarding ATP levels?

It has dual ATP binding sites that regulate glycolysis depending on ATP levels.

What happens to the Krebs cycle when energy levels are low?

The cycle speeds up to produce more ATP.

What does beta oxidation generate from fatty acids?

Acetyl CoA molecules.

How many Acetyl CoA molecules are produced from a triglyceride with three 10-carbon fatty acid chains?

Fifteen Acetyl CoA molecules.

What happens during photorespiration initiated by RuBisCO binding O₂ instead of CO₂?

It produces G3P and phosphoglycolate (PG), consuming ATP and releasing CO₂.

How do C₄ and CAM plants reduce photorespiration?

C₄ plants use spatial separation for CO₂ fixation; CAM plants use temporal separation.