Edexcel International A Level Biology: Respiration

Where is the electron transport chain located in the mitochondria?

What is the function of the intermembrane space in the mitochondria?

What is the site of ATP synthesis in the mitochondria?

What is the structure of the outer membrane of the mitochondria?

What is found in the matrix of the mitochondria?

What is the main respiratory substrate used by cells?

Where does glycolysis take place?

What is the equation for aerobic respiration using glucose?

In which location does the Krebs cycle take place?

What is the role of ATP in aerobic respiration?

Which coenzymes are responsible for transferring hydrogen between molecules during respiration?

What would happen if a large amount of energy was suddenly released during aerobic respiration?

What determines the overall rate of aerobic respiration?

What is the main fuel for respiration?

What is responsible for the transfer of acetate from one molecule to another during respiration?

Mitochondria Structure and Function

The electron transport chain is located in the inner mitochondrial membrane.
The intermembrane space plays a crucial role in creating a proton gradient used to generate ATP.
ATP synthesis occurs primarily in the mitochondrial matrix through ATP synthase during oxidative phosphorylation.
The outer membrane of the mitochondria is composed of a lipid bilayer rich in proteins and has porins that allow small molecules to pass through.

Mitochondrial Matrix

The matrix contains enzymes for the Krebs cycle, mitochondrial DNA, ribosomes, and substrates for metabolic processes.
The main respiratory substrate utilized by cells is glucose, though fatty acids and amino acids can also serve as substrates.

Cellular Respiration

Glycolysis occurs in the cytoplasm, breaking down glucose into pyruvate and generating small amounts of ATP and NADH.
The equation for aerobic respiration using glucose is:
- Glucose + 6 O2 → 6 CO2 + 6 H2O + Energy (ATP).
The Krebs cycle occurs in the mitochondrial matrix and is essential for generating electron carriers (NADH, FADH2) for the electron transport chain.

Energy Dynamics and Regulation

ATP serves as the primary energy currency in aerobic respiration, providing energy for cellular processes.
Coenzymes such as NAD+ and FAD are responsible for transferring hydrogen atoms between molecules during respiration.
A sudden release of a large amount of energy during aerobic respiration could lead to cellular damage or death due to excessive heat and reactive oxygen species formation.
The overall rate of aerobic respiration is determined by factors like substrate availability, enzyme activity, and the concentration of ADP and ATP.

Fuel and Transfer Mechanism

The main fuel for respiration in most cells is glucose.
Coenzyme A facilitates the transfer of acetate groups during respiration, helping in various metabolic pathways.

Test your knowledge of respiration with this quiz covering topics such as overview of respiration, glycolysis, link reaction & Krebs cycle, the electron transport chain, anaerobic respiration, respiratory quotient, and core practicals on investigation of respiration in yeast and using a respirometer.