Cellular Respiration

What is the overall formula for cellular respiration?

C6H12O6 + 6O2 → 6CO2 + 6H2O + ATP.

What happens during Glycolysis?

One glucose molecule is converted into two pyruvate molecules, with a net yield of 2 ATP.

Where does the Krebs Cycle occur?

In the mitochondrial matrix.

What are the products of the Krebs Cycle?

2 ATP, NADH, and FADH2.

How many times does the Krebs Cycle turn for each glucose molecule?

Twice.

What role do NADH and FADH2 play in cellular respiration?

They carry high-energy electrons to the Electron Transport Chain.

What generates the proton gradient in the Electron Transport Chain?

The transfer of electrons through proteins in the inner mitochondrial membrane.

What is chemiosmosis?

The process by which ATP is synthesized using the energy from the proton gradient.

What occurs in the absence of oxygen during fermentation?

NAD+ is regenerated for glycolysis, allowing continued ATP production.

What is the efficiency of ATP production in fermentation compared to aerobic respiration?

Fermentation yields only 2 ATP, while aerobic respiration yields up to 36 ATP.

Why are mitochondria important for energy production?

They produce ATP through the Electron Transport Chain and Krebs Cycle.

What happens to lactic acid produced during Lactic Acid Fermentation?

It can accumulate, possibly leading to muscle soreness.

How do muscle cells benefit from having more mitochondria?

More mitochondria enhance ATP production, improving endurance and reducing reliance on fermentation.

What is the significance of the proton motive force?

It drives ATP synthesis via ATP synthase during oxidative phosphorylation.

Cellular respiration

A series of metabolic pathways that convert carbohydrates into ATP, the energy currency of the cell.

ATP

Adenosine triphosphate, the energy currency of the cell, produced during cellular respiration.

Glycolysis

The first step of cellular respiration occurring in the cytoplasm, converting glucose into two pyruvate molecules and producing a net yield of 2 ATP.

Krebs Cycle

The second stage of cellular respiration, occurring in the mitochondrial matrix, processing acetyl groups and producing ATP, NADH, and FADH2.

Electron Transport Chain

The third stage of cellular respiration that takes place across the inner mitochondrial membrane, utilizing electrons from NADH and FADH2 to generate approximately 32 ATP.

Fermentation

A process that occurs in the absence of oxygen, regenerating NAD+ for glycolysis and yielding only 2 ATP per glucose molecule.

Alcoholic Fermentation

Type of fermentation that converts pyruvate into ethanol and carbon dioxide, commonly occurring in yeast and some bacteria.

Lactic Acid Fermentation

Type of fermentation occurring in animal cells, particularly during intense exercise, where pyruvate is converted to lactic acid.

Aerobic Respiration

Respiration that occurs in the presence of oxygen, yielding a total of 36 ATP per glucose molecule.

Anaerobic Respiration

Respiration that occurs without oxygen, yielding significantly less ATP (only 2 ATP).

Mitochondria

Organelles that play a crucial role in ATP production via the Krebs cycle and electron transport chain.

ATP Synthase

An enzyme that synthesizes ATP using the proton motive force established by the electron transport chain.

Glycolysis Overview

The first stage of cellular respiration that converts glucose into two molecules of pyruvate, producing a net yield of 2 ATP and 2 NADH.

Hexokinase

An enzyme that catalyzes the first step of glycolysis, converting glucose into glucose-6-phosphate, trapping glucose in the cell.

Fructose-1,6-bisphosphate

An important intermediate in glycolysis, formed from glucose-6-phosphate and cleaved into two three-carbon molecules.

PGAL (Glyceraldehyde-3-phosphate)

A three-carbon compound formed during glycolysis that is crucial for the formation of ATP and NADH.

Phosphorylation

The addition of a phosphate group to a molecule, which is essential in the energy investment phase of glycolysis.

Pyruvate Oxidation

The conversion of pyruvate into acetyl-CoA before entering the Krebs cycle, releasing CO2 and producing NADH.

Acetyl-CoA

The molecule formed from pyruvate that enters the Krebs cycle; it is the product of pyruvate oxidation.

Oxaloacetate

The four-carbon molecule that combines with acetyl-CoA to form citrate in the Krebs cycle.

Citrate

A six-carbon molecule formed from acetyl-CoA and oxaloacetate in the Krebs cycle, which undergoes transformations to release energy.

NAD+

A coenzyme that acts as an electron carrier in cellular respiration, reduced to NADH during glycolysis and the Krebs cycle.

FAD

Another coenzyme that accepts electrons during the Krebs cycle, reduced to FADH2, carrying energy to the electron transport chain.

Chemiosmosis

The process that utilizes the proton gradient generated by the electron transport chain to produce ATP through ATP synthase.

Proton Gradient

A difference in hydrogen ion concentration across the mitochondrial inner membrane that drives ATP synthesis.

Cytochromes

Proteins in the electron transport chain that contain heme groups and play a crucial role in transferring electrons.

ATP Yield per Glucose

In cellular respiration, the total yield is approximately 36 ATP from one molecule of glucose under aerobic conditions.

Lactic Acid

A byproduct of lactic acid fermentation, which is produced in muscle cells during anaerobic conditions.

Ethanol

The alcohol produced as a result of alcoholic fermentation in yeast and certain bacteria, along with carbon dioxide.

Fermentation Efficiency

Fermentation produces only 2 ATP from one glucose molecule, making it less efficient than aerobic respiration.

Metabolic Pathways

Complex series of enzymatic reactions in cellular respiration that allow for the efficient conversion of glucose into ATP.

Role of Mitochondria

The mitochondria are known as the powerhouse of the cell, central to energy production via aerobic processes.

Mitochondrial Matrix

The space within the inner membrane of mitochondria where the Krebs cycle occurs and contains enzymes for ATP production.