2.8 Cell respiration Notes

Introduction

Cell respiration is a fundamental biological process that involves the conversion of organic molecules into energy. This energy is captured in the form of adenosine triphosphate (ATP), which cells use to perform various functions. This study note will cover the key aspects of cell respiration as outlined in the International Baccalaureate (IB) Biology syllabus, including the stages of respiration, the differences between aerobic and anaerobic respiration, and the specific processes involved in each stage.

Overview of Respiration

Respiration is the process by which cells convert organic matter, particularly glucose, into carbon dioxide, water, and energy. This energy is stored in the form of ATP, which cells use for various activities such as growth and repair.

Types of Respiration

There are two main types of respiration:

1. Aerobic Respiration: This type of respiration requires oxygen and produces a large amount of ATP.
2. Anaerobic Respiration: This type of respiration does not require oxygen and produces a smaller amount of ATP.

General Equation for Aerobic Respiration

The overall chemical equation for aerobic respiration can be summarized as:

$$ \text{Glucose} + \text{Oxygen} \rightarrow \text{Carbon Dioxide} + \text{Water} + \text{Energy (ATP)} $$

Stages of Aerobic Respiration

Aerobic respiration can be divided into four main stages:

1. Glycolysis
2. Link Reaction
3. Krebs Cycle
4. Oxidative Phosphorylation

Each stage occurs in specific locations within the cell and involves a series of biochemical reactions.

Glycolysis

• Location: Cytoplasm
• Process: Glycolysis begins with one molecule of glucose and ends with two molecules of pyruvate. This process also produces a net gain of 2 ATP molecules and 2 NADH molecules.
• Equation: $$ \text{Glucose} + 2 \text{NAD}^+ + 2 \text{ADP} + 2 \text{P}_i \rightarrow 2 \text{Pyruvate} + 2 \text{NADH} + 2 \text{ATP} + 2 \text{H}_2\text{O} $$

Link Reaction

• Location: Matrix of the Mitochondria