Respiration

Question 1

Aerobic respiration summary

Answer 1

Needs oxygen
More efficient as more atp per molecule of glucose
Complete breakdown of glucose to form carbon dioxide and atp (lots)
Slow
Glycolysis, link reaction, Krebs cycle, oxidative phosphorylation

Question 2

Anaerobic respiration summary

Answer 2

Doesn’t need oxygen
Less efficient
Incomplete breakdown of glucose, makes harmful waste products (animals and bacteria produce lactic acid and plants and yeast produce ethanol
Fast
Glycolysis only

Question 3

Alternative respiratory substances

Answer 3

Other substances that can be oxidised by cells to release energy
Lipids and proteins

Question 4

Lipids

Answer 4

Hydrolysed to glycerol and fatty acids
Glycerol is phosphorylated into triose phosphate which can enter glycolysis
Fatty acids broken down into 2-carbon fragment that is converted to acetyl coenzyme A to enter the Krebs cycle
Oxidation of lipids produces 2-carbon fragments of carbohydrates and many hydrogens which are used to produce atp during oxidative phosphorylation

Question 5

Lipids vs carbs

Answer 5

Release more the. Double the energy of the same mass of carbohydrates

Question 6

Proteins

Answer 6

First hydrolysed to amino acids
Amino group removed (deamination) before entering the respiratory pathway depending on the number of carbon atoms
3- carbon compounds converted to pyruvate
4 and 5 carbon compounds converted to intermediates in the Krebs cycle

Question 7

Aerobic respiration, glycolysis

Answer 7

Cytoplasm
Anaerobic
Net yield is 2ATP and 2NADH
Glucose is phosphorylated by adding ATP.
Triose phosphate is oxidised to form pyruvate
Pyruvate is actively transported into the mitochondria for link reaction

Question 8

Phosphorylation of glucose in glycolysis

Answer 8

This is to make the glucose more reactive. Energy released by the hydrolysis of atp lowers activation energy of later enzyme controlled reactions

Question 9

Oxidation of triose phosphate

Answer 9

Hydrogen is removed from each of the two triose phosphate molecules and transferred to NAD to produce NADH

Question 10

Glycolysis as indirect evidence for evolution

Answer 10

It’s a universal feature of every living organism

Question 11

Link reaction

Answer 11

Matrix of mitochondria
Pyruvate is dehydrogenated and decarboxylated to form acetate
Acetate combines with co enzyme A to form acetyl co enzyme A
Products per reaction: 1 CO2 and 1NADH (x2 for per glucose)

Question 12

Krebs cycle

Answer 12

Matrix of mitochondria
Acetyl CoA joins a 4 carbon compound to form a 6 carbon compound, the co enzyme A is recycled
The 6 carbon compound is decarboxylated and dehydrogenated (NAD-NADH) to form a 5 carbon compound
5 carbon compound —> 4 carbon compound: 2NAD-2NADH, ADP+Pi—> ATP, FAD-FADH, decarboxylation (substrate level phosphorylation)
The 4 carbon molecule can combine with a new molecule of acetyl coenzyme A

Question 13

Substrate level phosphorylation

Answer 13

Phosphate is added to ADP from another molecule

Question 14

Products of Krebs cycle (per cycle)

Answer 14

3 NADH
1 ATP
1FADH
3 CO2