EN: Respiration and Anaerobic Respiration Flashcards
What is the difference between aerobic and anaerobic respiration?
Aerobic = requires oxygen, produces ATP.
Anaerobic = doesn’t require oxygen, produces less ATP than aerobic.
Both start with glycolysis.
Briefly describe the process of glycolysis:
A molecule of glucose is split into two smaller molecules of pyruvate.
Where does glycolysis occur?
In the cytoplasm.
Does glycolysis take place in aerobic or anaerobic respiration?
The first stage in both.
It doesn’t need oxygen to take place though - so it’s an anaerobic process.
What are the two stages in glycolysis?
Phosphorylation and oxidation.
In glycolysis, what is there an overall net gain of?
2 ATP and 2 reduced NAD
Describe the first stage of glycolysis:
Phosphorylation
- Glucose is phosphorylated using phosphate from ATP - creates 1 molecule of glucose phosphate and 1 molecule of ADP.
- ATP is then used to add another phosphate - hexose bisphosphate forms.
- Hexose bisphosphate is then split into 2 molecules of triose phosphate.
Describe the second stage of glycolysis:
Oxidation
- Triose phosphate is oxidised (loses hydrogen) - 2 molecules of pyruvate form.
- NAD collects hydrogen ions, forming 2 reduced NAD.
- 4 ATP are produced, but 2 were used up in stage 1, so there’s a net gain of 2.
Draw a diagram of glycolysis:
In aerobic respiration, what happens to the:
- two molecules of reduced NAD?
- two molecules of pyruvate?
- Reduced NAD - go to oxidative phosphorylation.
- Pyruvate - actively transported into the matrix of mitochondria for the link reaction.
In anaerobic respiration, what is the pyruvate produced in glycolysis converted to?
What aids this?
Ethanol (in plants and yeast) or lactate (in animal cells and some bacteria).
Reduced NAD facilitates this.
The production of ethanol or lactate in anaerobic respiration does what?
What does this mean?
Regenerates oxidised NAD.
This means glycolysis can continue even when there isn’t much oxygen around, so a small amount of ATP can still be produced to keep biological processes going.
Draw a diagram for alcohol fermentation:
Pyruvate conversion in anaerobic respiration in plants.
Draw a diagram of lactate fermentation:
Pyruvate conversion in anaerobic respiration in animals.
How many molecules of ATP does glycolysis yield per molecule of glucose?
2
Why is pyruvate reduced in the anaerobic respiration of both plants and animals?
To regenerate NAD in its oxidised state.
Draw a diagram representing the anaerobic respiration of animals:
- Pyruvate is redcued to lactate, regenerating oxidised NAD.
What happens if there is a build up of lactate in the body?
What needs to happen to combat this?
The muscle can cramp.
So, lactate needs to be oxidised back to pyruvate when oxygen is available. The extra oxygen needed for this is known as oxygen debt.
Draw a diagram representing the anaerobic respiration of plants and microorganisms:
Why does the pH of muscles fall during strenuous exercise?
The cells begin to respire anaerobically, which produces lactate.
This is acidic and so lowers the pH of the muscle.
Once oxygen debt has been repaird and all the lactate has been oxidised to pyruvate, what can happen to the pyruvate?
It could go into the link reaction or it can be stored as glycogen.
What happens to the ethanol produced during the anaerobic respiration of plants?
It is disposed of as a waste product.
