2.8 AND 8.2 Cell Respiration

Question 1

Mitochondrion

Answer 1

Has:
* Own DNA
* Double membrane
* 70s Ribosomes = mitochondrial gene production

Outer membrane = seperate conditions for aerobic respiration

Inner = e- transport chain and ATP synthase

Christae = increases SA to speed up reactions

Intermembrane space = protons pumped by e- transport chain

Matrix = contains enzymes for keen cycle and link reaction

Question 2

Order of Aerobic respiration

Answer 2

1. Glycolysis
2. Link reaction
3. Kreb cycle
4. E- transport chain
5. ATP synthase

Question 3

Glycolysis steps (cytoplasm)

Answer 3

1. Starts with a glucose
2. ATP is oxydized and adds a P to a 6C molecule, ADP is created and Glucose 6-phosphate is formed.
3. another ATP is oxidized and P is added to the Glucose 6-phosphate to form Fructose 1,6 bis phosphate.
4. Fructose 1,6 bis phosphate is split into 2x 3-carbon sugars.
5. 2x3c is then oxidised and NAD+ is reduced (gaining another H+).
6. This allows 2x3c to gain another P
7. Enzymes remove a P to form an ATP
8. Enzymes remove a P to form another ATP again
9. Pyruvate is formed with 2x ATP

Net total = 2 ATP, 2 NADH, 2 Pyruvate

Question 4

Link reaction steps

Answer 4

1. Each pyruvate is decarboxylated and CO2 is removed as a waste product
2. Each pyruvate is then oxidised (losing e- and H+)
3. This allows NAD+ to be reduced
4. Acetyl compound is formed
5. Acetyl compound reacts with Coenzyme-A to form Acetyl CoA.

Question 5

Kreb cycle steps

Answer 5

(Matrix)

1. Acetyl CoA binds to a 4 carbon molecule to form a 6 carbon compound
2. Decarboxylated and oxidised to reduce NAD+ into NADH leaving a 5 carbon compound
3. Decarboxylated and oxidised again to reduce a second NAD+ into NADH leaving a 4 carbon compound while also reducing ADP
4. 4 carbon molecule is oxidised, reducing FAD2- and NAD+ creating a new 4 carbon molecule to be used in the cycle again
   * Must be done twice to complete both pyruvate molecules

Question 6

Electron transport chain

Answer 6

(Christae)

1. NADH donates 2 electrons and it’s hydrogen to the first of four enzymes. Allowing its hydrogen to flow into the intermembrane space.
2. FADH2 releases a hydrogen and electrons to be carried to the third enzyme.
3. At the third enzyme the hydrogen diffuses into the intermembrane space.
4. The electrons carry on to the 4th enzyme allowing hydrogens to diffuse into the intermembrane space further filling the concentration.
5. The left over e- are used by an oxygen to bind with 2 hydrogens to form water.
6. When the hydrogen ion gradient is higher than in the matrix ATP synthase kicks in. As hydrogen diffuses down concentration energy is released through phosphorylation adding a P to ATP.

Question 7

Anaerobic respiration

Answer 7

Undergoes anaerobic respiration with:
1. Alcoholic fermentation
OR
2. Lactic acid fermentation

Produces no ATP
Uses no Oxygen

restore stocks of NAD+ (because it is needed for glycolysis)

Question 8

Lactic acid fermentation

Answer 8

1. Glycolysis occurs to form 2 pyruvate
2. Each pyruvate uses NADH2 to form 2 Lactate

Glucose –> 2x Pyruvate –> 2x Lactic acid

Question 9

Alcoholic fermentation

Answer 9

1. Glycolysis
2. Each Pyruvate is decarboxylated forming 2 Acetaldehyde
3. 2 NADH2 are oxidised to form 2 Ethanol

Question 10

Why glucose is used as an energy source

Answer 10

Energy is stored in the covalend bonds;
Series of enzymes break each covalent bond (one at a time)

Energy is released when each covalent bond is broken
Energy released is trapped in ATP

Question 11

ATP, lipids, glucose

Answer 11

ATP energy is used immediately
Lipids = long term energy storage
Glucose = short term energy storage

Question 12

ATP

Answer 12

high energy molecule that functions as an immediate source of energy for cell processes

When ATP is hydrolysed (to form ADP + P) the energy stored in the phophate bond is released to be used by the cell

Question 13

Lactic acid in muscles

Answer 13

Muscle contractions require high levels of ATP
At high levels of exercise, the cells demand for energy will exceed the O2 availability
- Therefore Anaerobic respiration occurs

Lactic acid is the product and builds up in the muscle
- it is eventually washed out and carried away by the blood stream and taken to liver to be filtered out

Question 14

oxidation, reduction, decarboxylation, phosphorolation, hydrolysis

Answer 14

Oxydation = loses e- and H+ (GAIN O2)
Reduction = gain e- (LOSE O2)

LEO GER = Loss of Electrons is Oxidation ; Gain of Electrons is Reduction

Decarboxylation = Carbon atoms are removed from the organic molecule

Phosphorolation = Energy released from the breakdown of glucose is used to phosphorylate ADP to make ATP

hydrolysis = use H2O to break covalent bond

Question 15

Summary of ATP Production

Answer 15

Question 16

Cell Respiration

Answer 16

the controlled release of energy from organic compounds to produce ATP.