Cellular Respiration: Harvesting Energy

How many NADH molecules are produced from one glucose molecule during pyruvate oxidation?

What is the main goal of the electron transport chain (ETC) in oxidative phosphorylation?

How many ATP molecules can potentially be produced from one glucose molecule based on maximum yields from all processes?

Which of the following molecules is NOT an electron carrier in the electron transport chain?

What is the range of potential total ATP yield from one glucose molecule when considering shuttle inefficiencies?

What is the primary product produced by glycolysis?

During the energy investment phase of glycolysis, how many ATP molecules are consumed?

Where does glycolysis occur within a cell?

What is the net gain of ATP from one molecule of glucose during glycolysis?

Which of the following is NOT a step in the energy investment phase of glycolysis?

What component is generated during the citric acid cycle?

Which of the following pathways is NOT part of cellular respiration?

What happens during the second phosphorylation step in glycolysis?

Energy and ATP

Cells primarily use ATP (Adenosine Triphosphate) as their energy source.
ATP is produced during the process of cellular respiration, which metabolizes glucose.

Sources of Glucose

Glucose is obtained from:
- Starch consumption
- Glycogen

Cellular Respiration Overview

Cellular respiration encompasses three main pathways:
- Glycolysis
- Citric Acid Cycle (TCA/Krebs Cycle)
- Oxidative Phosphorylation (ETC and Chemiosmosis)

Glycolysis

Known as "sugar splitting," glycolysis breaks down glucose for energy.
Takes place in the cytosol of the cell.

Glycolysis Phases

Energy Investment Phase:
- Consumes 2 ATP.
- Includes steps of phosphorylation, isomerization, second phosphorylation, cleavage, and conversion of DHAP into GADP/G3P.
Energy Payoff Phase:
- Produces a net gain of 2 ATP and 2 NADH from 1 glucose molecule.
- Includes oxidation, dephosphorylation, phosphate transfer, dehydration, and second dephosphorylation.

Energy Input and Output of Glycolysis

Input: Glucose + 2 ATP
Output: 2 Pyruvate + 4 ATP
Net result: 2 ATP and 2 NADH per glucose molecule.

Citric Acid Cycle

Also called the Krebs Cycle, it continues the oxidation of organic molecules.
Takes place in the mitochondrial matrix.
Produces energy yielding products:
- 3 NADH
- 1 FADH2
- 1 GTP per glucose molecule.

Oxidative Phosphorylation

Involves electron carriers (NADH and FADH2) transferring electrons to oxygen.
The process couples energy from electron acceptors to generate an ATP synthesis-driving proton gradient.
Electron Transport Chain (ETC) consists of various proteins in the inner mitochondrial membrane, including FMN, Fe-S, and Ubiquinone.

ATP Yield from Cellular Respiration

Total potential ATP yield from one glucose molecule can vary between 30 to 38 ATP:
- Glycolysis: 2 ATP + 2 NADH (potentially yielding 5 ATP)
- Pyruvate Metabolism: 4 NADH (yielding roughly 10 ATP)
- Citric Acid Cycle: 2 ATP + 6 NADH (yielding roughly 15 ATP) + 2 FADH (yielding 3 ATP)
Efficiency of shuttles can affect total yield.

ATP Number Discrepancies

Factors include variations in electron shuttle efficiency and the proton motive force in oxidative phosphorylation.

This quiz focuses on the process of cellular respiration, which is the metabolic pathway that converts glucose into ATP, the energy currency of the cell. It covers key concepts such as sources of glucose and the importance of ATP in cellular functions. Test your understanding of how energy is harvested in living organisms!