lecture 15 cell respiration citric acid cycle

What are the main stages of cellular respiration?

Glycolysis, Pyruvate Oxidation, Citric Acid Cycle, Electron Transport Chain

Where does glycolysis occur in eukaryotes and prokaryotes?

In eukaryotes: cytoplasm; In prokaryotes: cytoplasm

What is the starting molecule for pyruvate oxidation?

Pyruvate, produced from glycolysis

What are the end products of pyruvate oxidation?

Acetyl CoA, NADH, and CO2

Where does pyruvate oxidation occur in eukaryotes?

In the mitochondrial matrix

What is the main function of the citric acid cycle?

To decompose citrate (C6) to oxaloacetate (C4) and produce energy carriers

How many ATP are produced per molecule of glucose in the citric acid cycle?

2 ATP (substrate-level phosphorylation)

What are the high-energy electron carriers produced in the citric acid cycle?

6 NADH and 2 FADH2

What is released as a byproduct of the citric acid cycle?

4 CO2

Where does the electron transport chain occur in eukaryotes?

In the inner mitochondrial membrane

What is the final electron acceptor in the electron transport chain?

Oxygen (O2)

What is the role of ATP synthase in cellular respiration?

To synthesize ATP using the proton-motive force

How does the electron transport chain contribute to ATP production?

It creates a proton gradient that drives ATP synthesis through chemiosmosis

What is the energy flow in cellular respiration?

Glucose → NADH → electron transport chain → proton-motive force → ATP

What percentage of potential chemical energy in glucose is transferred to ATP?

About 34%

What is the efficiency of respiration in kcal/mol?

ΔG = -686 kcal/mol (glucose to CO2) and ΔG = 7.3 kcal/mol (ADP to ATP)

What is the purpose of glycolysis?

To break down glucose into pyruvate, producing a small amount of ATP and NADH

What is the significance of the proton-motive force?

It is the energy source for ATP synthesis via chemiosmosis

What happens to the carbon atoms during the citric acid cycle?

They are released as CO2, the most oxidized form of carbon

What is the role of NAD+ in pyruvate oxidation?

It acts as an oxidizing agent, being reduced to NADH

What is the starting molecule for the citric acid cycle?

Acetyl CoA

What are the main structural features of mitochondria involved in cellular respiration?

Outer membrane, inner membrane, intermembrane space, mitochondrial matrix

What is the significance of the chemiosmotic model?

It explains how ATP is synthesized by oxidative phosphorylation

Which complexes in the electron transport chain generate the proton gradient?

Complexes I, III, and IV

What is the net energy yield from glycolysis?

2 ATP and 2 NADH per glucose molecule