12.2.1
Introduction to Respiration
Respiration
Respiration
Respiration is a series of reactions that convert chemical energy stored in carbohydrates into ATP. It takes place in the mitochondria of eukaryotic cells.


Importance of respiration
Importance of respiration
- Respiration is the process that converts energy within the bonds of glucose into a more readily available form: ATP. The equation for respiration is:
- 6O2 + C6H12O6 (glucose) → 6CO2 + 6H2O


Types of respiration
Types of respiration
- There are two types of respiration:
- Aerobic - respiration using oxygen.
- Anaerobic - respiration without oxygen.
- Both types of respiration start with the same stage: glycolysis (pictured).


Anaerobic respiration
Anaerobic respiration
- Anaerobic respiration does NOT use oxygen (e.g. short burst of intense exercise).
- There are two types of anaerobic respiration:
- Ethanol fermentation - takes place in plants and yeast.
- Lactate fermentation - takes place in animals.


Aerobic respiration
Aerobic respiration
- Aerobic respiration uses oxygen (e.g. extended periods of exercise).
- The reaction and products are the same in plants, animal and yeast.
- Aerobic respiration also differs from anaerobic respiration in the following ways:
- Water is produced.
- More ATP is produced.
- Glucose is fully broken down.
- After glycolysis, there are more steps (the link reaction, the Krebs cycle and oxidative phosphorylation).
Glycolysis
Glycolysis
Respiration produces ATP and can be either aerobic or anaerobic. Glycolysis is the first stage in both these processes. Glycolysis happens in the cytoplasm and is an anaerobic process.


Phosphorylation
Phosphorylation
- The first step in glycolysis involves the phosphorylation of glucose to glucose phosphate using one molecule of ATP.
- Glucose phosphate is phosphorylated by another molecule of ATP to hexose bisphosphate (a six-carbon molecule)
- Hexose bisphosphate splits into two molecules of triose phosphate (TP).


Oxidation
Oxidation
- The two molecules of TP are oxidised to pyruvate (another three-carbon molecule) in a multi-step reaction.
- A single TP molecule produces two molecules of ATP and one molecule of reduced NAD (NADH) in this process.


Net gain
Net gain
- 2 ATP molecules.
- 2 NADH molecules.
1Cell Structure
1.1Cell Structure
1.1.1Studying Cells - Microscopes
1.1.2Introduction to Eukaryotic & Prokaryotic Cells
1.1.3Ultrastructure of Eukaryotic Cells
1.1.4Ultrastructure of Eukaryotic Cells 2
1.1.5Ultrastructure of Eukaryotic Cells 3
1.1.6Prokaryotic Cells
1.1.7Viruses
1.1.8End of Topic Test - Cell Structure
1.1.9Exam-Style Question - Microscopes
1.1.10A-A* (AO2/3) - Cell Structure
2Biological Molecules
2.1Testing for Biological Modules
2.2Carbohydrates & Lipids
2.3Proteins
3Enzymes
4Cell Membranes & Transport
4.1Biological Membranes
5The Mitotic Cell Cycle
6Nucleic Acids & Protein Synthesis
6.1Nucleic Acids
7Transport in Plants
8Transport in Mammals
8.1Circulatory System
8.2Transport of Oxygen & Carbon Dioxide
9Gas Exchange
9.1Gas Exchange System
10Infectious Diseases
10.1Infectious Diseases
10.2Antibiotics
11Immunity
12Energy & Respiration (A2 Only)
13Photosynthesis (A2 Only)
14Homeostasis (A2 Only)
14.1Homeostasis
14.2The Kidney
14.3Cell Signalling
14.4Blood Glucose Concentration
14.5Homeostasis in Plants
15Control & Coordination (A2 Only)
15.1Control & Coordination in Mammals
15.1.1Neurones
15.1.2Receptors
15.1.3Taste
15.1.4Reflexes
15.1.5Action Potentials
15.1.6Saltatory Conduction
15.1.7Synapses
15.1.8Cholinergic Synnapses
15.1.9Neuromuscular Junction
15.1.10Skeletal Muscle
15.1.11Sliding Filament Theory Contraction
15.1.12Sliding Filament Theory Contraction 2
15.1.13Menstruation
15.1.14Contraceptive Pill
15.2Control & Co-Ordination in Plants
16Inherited Change (A2 Only)
16.1Passage of Information to Offspring
16.2Genes & Phenotype
17Selection & Evolution (A2 Only)
17.2Natural & Artificial Selection
18Classification & Conservation (A2 Only)
18.1Biodiversity
18.2Classification
19Genetic Technology (A2 Only)
19.1Manipulating Genomes
19.2Genetic Technology Applied to Medicine
19.3Genetically Modified Organisms in Agriculture
Jump to other topics
1Cell Structure
1.1Cell Structure
1.1.1Studying Cells - Microscopes
1.1.2Introduction to Eukaryotic & Prokaryotic Cells
1.1.3Ultrastructure of Eukaryotic Cells
1.1.4Ultrastructure of Eukaryotic Cells 2
1.1.5Ultrastructure of Eukaryotic Cells 3
1.1.6Prokaryotic Cells
1.1.7Viruses
1.1.8End of Topic Test - Cell Structure
1.1.9Exam-Style Question - Microscopes
1.1.10A-A* (AO2/3) - Cell Structure
2Biological Molecules
2.1Testing for Biological Modules
2.2Carbohydrates & Lipids
2.3Proteins
3Enzymes
4Cell Membranes & Transport
4.1Biological Membranes
5The Mitotic Cell Cycle
6Nucleic Acids & Protein Synthesis
6.1Nucleic Acids
7Transport in Plants
8Transport in Mammals
8.1Circulatory System
8.2Transport of Oxygen & Carbon Dioxide
9Gas Exchange
9.1Gas Exchange System
10Infectious Diseases
10.1Infectious Diseases
10.2Antibiotics
11Immunity
12Energy & Respiration (A2 Only)
13Photosynthesis (A2 Only)
14Homeostasis (A2 Only)
14.1Homeostasis
14.2The Kidney
14.3Cell Signalling
14.4Blood Glucose Concentration
14.5Homeostasis in Plants
15Control & Coordination (A2 Only)
15.1Control & Coordination in Mammals
15.1.1Neurones
15.1.2Receptors
15.1.3Taste
15.1.4Reflexes
15.1.5Action Potentials
15.1.6Saltatory Conduction
15.1.7Synapses
15.1.8Cholinergic Synnapses
15.1.9Neuromuscular Junction
15.1.10Skeletal Muscle
15.1.11Sliding Filament Theory Contraction
15.1.12Sliding Filament Theory Contraction 2
15.1.13Menstruation
15.1.14Contraceptive Pill
15.2Control & Co-Ordination in Plants
16Inherited Change (A2 Only)
16.1Passage of Information to Offspring
16.2Genes & Phenotype
17Selection & Evolution (A2 Only)
17.2Natural & Artificial Selection
18Classification & Conservation (A2 Only)
18.1Biodiversity
18.2Classification
19Genetic Technology (A2 Only)
19.1Manipulating Genomes
19.2Genetic Technology Applied to Medicine
19.3Genetically Modified Organisms in Agriculture
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