Cellular Respiration: Glycolysis, Krebs Cycle, and Electron Transport

BIO 1200

What is the overall equation for cellular respiration?

C₆H₁₂O₆ + 6O₂ → 6CO₂ + 6H₂O + energy (ATP)

What are the four main stages of cellular respiration?

1) Glycolysis, 2) Breakdown of pyruvate, 3) Citric acid cycle (Krebs cycle), 4) Oxidative phosphorylation (ETC)

Where does glycolysis occur?

In the cytosol

Where does the breakdown of pyruvate take place?

In the mitochondrial matrix

What is produced during glycolysis?

2 ATP and 2 NADH from the breakdown of glucose into 2 pyruvate

What happens to pyruvate after glycolysis?

It is converted into acetyl CoA, producing 1 CO₂ and 1 NADH per pyruvate

What are the products of the citric acid cycle per acetyl CoA?

2 CO₂, 1 ATP, 3 NADH, and 1 FADH₂

What role does NADH play in cellular respiration?

NADH carries electrons to the electron transport chain (ETC) during oxidative phosphorylation

What is the function of ATP synthase?

It synthesizes ATP from ADP as protons flow through it, creating a rotary motion

How is an electrochemical gradient created in the ETC?

High-energy electrons from NADH are transferred to NADH dehydrogenase, pumping H+ into the intermembrane space

What is the net yield of ATP from glycolysis?

2 ATP (4 produced, but 2 are consumed)

What is a metabolic cycle?

Biochemical reactions that regenerate the first molecule in the pathway during the final step

What are the energy intermediates produced in the Krebs cycle?

FADH₂ (1 per acetyl CoA) and NADH (3 per acetyl CoA)

What is the role of the electron transport chain?

To transfer electrons and create an electrochemical gradient for ATP synthesis

What is the significance of the energy investment phase in glycolysis?

2 ATP are hydrolyzed to create fructose 1,6-bisphosphate, which primes glucose for further reactions

What happens during the cleavage phase of glycolysis?

The 6-carbon molecule is split into two 3-carbon molecules (G3P)

What is the final outcome of the energy liberation phase in glycolysis?

G3P is converted into 2 pyruvate, producing 2 NADH and 4 ATP

How do carbohydrates, proteins, and fats enter cellular respiration?

They utilize the same pathways but enter glycolysis or Krebs at different points