12.2.1

Respiration Reactions

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Respiration

Respiration is an exothermic reaction (releases energy) that supplies all the energy needed by living organisms. This reaction happens continuously in all living cells. The reaction can be aerobic (with oxygen) or anaerobic (without oxygen).

Aerobic respiration (with oxygen)

Aerobic respiration (with oxygen)

  • In aerobic respiration, glucose reacts with oxygen in the mitochondria of cells to give carbon dioxide, water and energy.
    • Glucose + oxygen → carbon dioxide + water
    • C6H12O6 + 6O2 → 6CO2 + 6H20
Anaerobic respiration in animals

Anaerobic respiration in animals

  • In animals, glucose is converted to lactic acid:
    • Glucose → lactic acid
  • Anaerobic respiration happens when not enough oxygen reaches the muscles during periods of intense activity.
Anaerobic respiration in yeast

Anaerobic respiration in yeast

  • In yeast cells, glucose is converted into ethanol and carbon dioxide.
    • Glucose → ethanol + carbon dioxide
    • C6H12O6 → 2C2H5OH + 2CO2
  • This process is called fermentation and is used to make bread and alcohol.
Jump to other topics
1

Classification of Living Organisms

2

Organisation of the Organism

3

Movement Into & Out of Cells

4

Biological Molecules

5

Enzymes

6

Plant Nutrition

7

Human Nutrition

8

Transport in Plants

9

Transport in Animals

10

Diseases & Immunity

11

Gas Exchange in Humans

12

Respiration

13

Excretion in Humans

14

Coordination & Response

15

Drugs

16

Reproduction

17

Inheritance

18

Variation & Selection

19

Organisms & Their Environment

20

Human Influence on Ecosystems

21

Biotechnology & Genetic Modification

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