Respiration

Question 1

What are the four stages in aerobic respiration?

Answer 1

1. Glycolysis
2. Link reaction
   3.Krebs cycle
3. Oxidative phosphorylation

Question 2

Where does glycolysis occur?

Answer 2

In the cytoplasm of the cell

Question 3

Where does the link reaction occur?

Answer 3

In the liquid matrix of the mitochondria

Question 4

Where does the Krebs cycle occur?

Answer 4

In the liquid matrix of the mitochondria

Question 5

Where does oxidative phosphorylation occur?

Answer 5

In the mitochondria membranes

Question 6

What are the two ways that ATP can be generated?

Answer 6

1. Substrate level phosphorylation.= ATP can be generated directly through energy released via respiration reaction such as glycolysis and Krebs cycle.
2. Oxidative phosphorylation= ATP, generated from chemical energy release when a coin enzyme such as FAD has been oxidised

Question 7

Process of glycolysis( splitting glucose)

Answer 7

1. In both aerobic and anaerobic respiration occurs in the cytoplasm.
2. glucose (6c)is a stable molecule which is activated by phosphorylation into glucose phosphate. This requires hydrolysis of two ATP molecules into ADP and pi
3. Glucose phosphate (3c)which is an unstable molecule, then splits by lysis into two triose phosphate phosphate molecules
4. Triose (3c) phosphate is oxidised into pyruvate. By a loss of hydrogen
5. Loss of hydrogen is used to reduce 2NAD molecules into NADH and and production of 4 ATP molecules

Question 8

Net gain yield in glycolysis

Answer 8

1. 2 ATP molecules by substate phosphorylation
2. 2 NADH
3. 2 3c pyruvate molecules

Question 9

Process of link reaction

Answer 9

1. In presence of oxygen pyruvate is actively transported into the liquid matrix in the mitochondria from the cytoplasm.
2. Pyruvate which is a 3 carbon molecule looses Carbon dioxide and becomes a 2c acetate by oxidation and reduces a NAD into NADH
3. Acetate which is a two carbon molecule combines with co-enzyme A produce acetal coenzyme A which enters the Krebs cycle

Question 10

Net yield in link reaction

Answer 10

1. 2 NADH molecules
2. 2 acetyl co enzyme A molecules
3. 2 CO2

Question 11

Process of Krebs cycle x2

Answer 11

1.Acetyl co enzyme a reacts with a four carbon molecule releasing co enzyme A and producing a 6 carbon molecule.
2. Six carbon molecule loses a carbon dioxide and oxidise to produce a five carbon molecule. NAD is reduced to NADH
3. Five carbon molecule produces a four carbon molecule by reduction of NAD and FAD into NADH and FADH by oxidation and loss of carbon dioxide
4. ATP produced formed by substrate level phosphorylation

Question 12

Net yield in Krebs cycle- 3:2:1:1

Answer 12

1. 6 NADH molecules into ADP
2. 2 FADH molecules
3. 2 ATP molecules
4. 4 CO2

Question 13

Process of oxidative phosphorylation

Answer 13

1. Reduced coenzyme molecules FADH and NADH are oxidised loosing hydrogen and electrons
   H=H+ +e-
2. Electrons passed down the Electron transfer chain by a series of redox reactions
3. Energy released to pump hydrogen ions across the inner mitochondria membrane into the inner membrane space
4. H+ ions diffuse down the electrochemical gradient through ATP synthesis embedded in the membrane back into the matrix
5. ATP scent catalyse condensation reaction of ATP from ADP and PI
6. Oxygen acts as a final terminal electron acceptor and produces water by combining with H+ ions and electrons to form water

Question 14

What reaction can only happen in an aerobic respiration and why?

Answer 14

Glycolysis can only happen as no oxygen required whereas an in the link, Krebs cycle and oxidative phosphorylation they stopped as no oxygen to act as terminal electron her so no electrochemical gradient form so no ATP.

Question 15

Anaerobic respiration in animals/yeast, plants , bacteria

Answer 15

1. Glucose which is a stable six carbon molecule is phosphorated into glucose phosphate using 2 ATP which is an unstable molecule and splits by lysis into 23C triose phosphate
2. Triose of phosphate is oxidised into pyruvate releasing a hydrogen to reduce NAD into NADH and forming 4 ATP molecules so net gain of two ATP molecules.
3. Pyruvate is reduced into lactate or ethanol and CO2 in plants, yeast and bacteria andNAD is regenerated back into the cycle

Question 16

Give two reasons why the respirometer was left for 10 minutes when it was first placed in the water bath

Answer 16

1. Equilibrium reach.
2. To allow pressure changes in apparatus
3. Allow respiration of seeds to stabilise

Question 17

How to measure rate of respiration

Answer 17

1. Distance the bubble move.
2. Fixed Time period
3. Cross-section of tube/ diameter

Question 18

Respirometer knowledge

Answer 18

1. Oxygen is used for aerobic respiration
2. This reduces the volume of oxygen in the tube, therefore reducing the pressure
3. A solution of potassium hydroxide absorbs the carbon dioxide released by the animal
4. Therefore, the ink moves from my higher to lower pressure along the graduated scale