IB DP Biology: HL复习笔记8.2.2 Overview of the Stages of Respiration

An overview of respiration

• Respiration involves the transfer of chemical potential energy from nutrient molecules (such as carbohydrates, fats and proteins) into a usable energy form (through the synthesis of ATP) that can be used for work within an organism
• It is a vital process that takes place in the cells of all living organisms
• There are two forms of respiration depending on the oxygen availability of the cell:
  • Aerobic respiration
  • Anaerobic respiration
• Aerobic respiration is the process of breaking down a respiratory substrate in order to produce ATP using oxygen
• Anaerobic respiration takes place in the absence of oxygen and also breaks down a respiratory substrate but produces less ATP for the cell
• The main respiratory substrate involved in respiration is glucose

Aerobic respiration

• Aerobic respiration can be summarised by the following equation
  • Glucose + oxygen →  carbon dioxide + water + energy

The stages of aerobic respiration

• The process of aerobic respiration using glucose can be split into four stages
• Each stage occurs at a particular location in a eukaryotic cell:
  • Glycolysis takes place in the cytoplasm
  • The link reaction takes place in the matrix of the mitochondria
  • The Krebs Cycle takes place in the matrix of the mitochondria
  • Oxidative phosphorylation which involves the electron transport chain and chemiosmosis and occurs at the inner membrane of the mitochondria

Overview of the four stages of aerobic respiration

Four Stages of Respiration Table