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
When does anaerobic respiration take place in animals?
Occurs during:
- Strenuous exercise
- Immediately after birth
- Animals living in water when reaching an area of low oxygen
What problems does lactate build up cause?
- Cramp & muscle fatigue
- Is an acid so causes pH changes which effect enzymes
Plants produce ATP in their chloroplasts during photosynthesis. They also produce ATP during respiration. Explain why it is important for plants to produce ATP during respiration in addition to during photosynthesis.
1.In the dark no ATP production in photosynthesis;
2. Some tissues unable to photosynthesise / produce ATP;
3.ATP cannot be moved from cell to cell / stored;
4.Plant uses more ATP than produced in photosynthesis;
5.ATP for active transport / synthesis (of named substance);
