Respiraton

Question 1

what is respiration

Answer 1

the process of which cells breakdown glucose to release energy to produce ATP

Question 2

what is aerobic respiration

Answer 2

requires oxygen and fully breaks down glucose to produce carbon dioxide, water and many ATP. It involves mitochondria

Question 3

What is the equation of respiration

Answer 3

Glucose + oxygen = carbon dioxide + water( + energy)

Question 4

what are coenzymes

Answer 4

these are molecules that some enzymes need to function Coenzymes in respiration are NAD,FAD and Coenzyme A

Question 5

what is phosphorylation, decarboxylation, oxidation, and Dehydrogenation?

Answer 5

• the addition of a phosphate group to a molecule
• loss of a carbon dioxide from a molecule
• loss of hydrogen atoms
• the loss of hydrogen atoms from a molecule

Question 6

what are the 4 stages of aerobic respiration

Answer 6

1. Glycolysis
2. the link reaction
3. the Krebs cycle
4. oxidative phosphorylation

Question 7

stage 1 - Glycolysis

Answer 7

this takes place in the cytoplasm, so doesn’t require energy. there are two parts of glycolysis: phosphorylation and oxidation
1. Firstly, ATP is used to phosphorylate glucose to triose phosphate
2. then triose phosphate is oxidised, releasing ATP. Overall, there’s a net gain of 2 ATP. Products of glycolysis: 2x pyruvate, 2x reduced NAD and 2x ATP.
3. After glycolysis, the two pyruvate molecules are actively transported into the matrix for the link reaction.

Question 8

stage 2 - link reaction

Answer 8

1. Pyruvate is decarboxylated, one carbon atom is removed from pyruvate in the form of CO2
2. NAD is reduced NADH, it collects hydrogen atoms from pyruvate changing into acetate.
3. Acetate is combined with Coenzyme A to form acetyl co enzyme A
4. the link reaction occurs twice for every glucose molecule. Products per link reaction 1x acetyl CoA, 1x reduced NAD and 1x CO2

Question 9

Stage 3 - Krebs cycle

Answer 9

the Krebs cycle involves a series of oxidation and reduction reactions, which take place in the matrix of the mitochondria
1. the cycle happens once for every pyruvate molecule, so it goes round twice for glucose molecule.
2. formation of a 6C(citrate): 2C acetyl Co enzymes A enters the Krebs cycle and combines with 4C called oxaloacetate to form a 6C intermediate called citrate and Co enzyme A which can be reused.
3. formation of a 5C intermediate:
the 6C intermediate is then decarboxylated and oxidised to form CO2 and reduced NAD and 5C intermediate
4. Regeneration of a 4C oxaloacetate: the 5C intermediate is again decarboxylated to release CO2 and oxidised 3 times to form 2x reduced NAD and 1x reduced FAD. Enough energy is released in one of the Krebs cycle to synthesise molecule of ATP from ADP+ Pi, i.e. substrate level phosphorylation. The product of these reactions is oxaloacetate and the cycle begins again.
For each turn of the Krebs cycle, 3x reduced NAD, 1xATP,1x reduced FAD, 2xCO2 released. For every glucose molecule, the Krebs cycle occurs twice as there are two acetyl co enzyme A molecules made. So, every glucose: 6 reduced NAD, 2ATP, 2 reduced FAD and 4 CO2 are released.

Question 10

anaerobic respiration

Answer 10

During vigorous exercise, it is not possible to deliver enough oxygen to our muscles to generate all the ATP we require through aerobic respiration alone.

To get additional ATP we need during this sort of exercise, we use anaerobic respiration which does NOT require oxygen.

Anaerobic respiration takes place in the cytoplasm. It is basically glycolysis. Glucose is NOT completely broken down which results in less ATP (2 ATP) being made.

The end product of glycolysis is pyruvate. But, for anaerobic respiration to continue the pyruvate is reduced by reduced NAD to produce lactate

This is to regenerate oxidised NAD which is needed for glycolysis