12.1 - 12.4 Respiration Flashcards
List the stages of aerobic respiration
- Glycolisis
- Link reaction
- Krebs cycle
- Oxidative phosphorylation
Describe the process of glycolysis
- One glucose (6C) undergoes phosphorylation, hydrolyising 2 ATP, to make phosphorylated glucose
- Phosphorylated glucose (6C) undergoes cleavage to form 2 triose phosphate
- Each triose phosphate (3C) undergoes oxidation, reforming 2 ATP and releasing 2 hydrogen to reduce NAD, to form pyruvate (3C)
Where does glycolysis take place?
Cytoplasm
What are the products of glycolysis? (for one glucose molecule)
- 2x ATP
- 2x reduced NAD
- 2x pyruvate
Describe the process of the link reaction
- Each pyruvate (3C) is converted to acetate (2C), reducing an NAD and releasing a CO2
- Each acetate (2C) reacts with coenzyme A to form acetyl coenzyme A (2C)
Where does the link reaction take place?
Matrix
What are the products of the link reaction? (for one molecule of glucose)
- 2x acetyle coenzyme A
- 2x CO2
- 2x reduced NAD
Describe the process of the Krebs cycle
- Each acetyl coenzyme A (2C) combines with a 4-carbon molecule to form a 6-carbon molecule
- Each 6-carbon molecule reduces and NAD, releases 2 CO2, reduces FAD and releases an ATP to reform a 4-carbon molecule which re-enters the cycle
Where does the krebs cycle take place?
Matrix
What are the products of the Kreb cycle? (for one glucose molecule)
- 6x reduced NAD
- 2x reduced FAD
- 2x ATP
- 4x CO2
Describe the process of oxidative phosphorylation
- Reduced NAD and reduced FAD from other steps of respiration transfer the electrons of the hydrogen atoms they are carrying to molecules at the start of the electron transfer chain
- The electrons pass along the electron transfer carrier chain molecules in a series of oxidation-reduction reactions
- The energy released is used to actively transport protons across the inner mitochondrial membrane from the mitochondrial matrix into the intermembrane space
- The protons accumulate in the intermembrane space
- They diffuse back into the mitochondrial matrix through ATP synthase channels in the inner membrane
- The flow of protons causes ATP synthase to change shape and cause ATP synthesis
- At the end of the chain the electrons combine with these protons and oxygen to form water
List the stages of anaerobic repiration
- Glycolysis
- Fermentation
Problems caused by lack of oxygen
Krebs cycle will stop:
- All FAD and NAD will be reduced with no oxygen ro reoxidise it
- No FAD or NAD will be available to take up the H+ produced during the Krebs cycle
- Enzymes will stop working
Glycolysis:
- All NAD will be reduced
- No NAD to remove hydrogen produced by glycolysis
- Glycolysis stops
Electron transfer chain will stop:
- No oxygen to act as final electron acceptor
Describe anaerobic respiration in plants and yeast
Pyruvate + reduced NAD -> ethanol + carbon dioxide + oxidised NAD
- Glycolysis forms pyruvate which then loses a molecule fo CO2 and accepts a H+ from reduced NAD to make ethanol
- Ethanol and carbon dioxide produced by yeast
Describe anaerobic respiration in animals
pyruvate + reduced NAD -> lactate + oxidised NAD
- Each pyruvate molecule takes up two hydrogen atoms from reduce NAD to form lactate
Lactate is removed by the blood and taken to the liver to be converted to gylcogen
