Topic 1 - Respiration

Question 1

What is the structure of ATP

Answer 1

Three phosphate groups combined with the nucleotide base adenine and a ribose sugar

Question 2

What is ATP synthesised from

Answer 2

ADP, a molecule with two phosphate groups and inorganic phosphate

Question 3

What is the process of ATP synthesising

Answer 3

Phosphorylation

Question 4

What makes ATP so suitable as an immediate energy source

Answer 4

Hydrolysis of ATP releases a relatively small amount of energy
The hydrolysis of ATP is a single reaction, releasing energy immediately
ATP can be transported around the cell easily, as it’s small and soluble

Question 5

What is substrate level-phosphorylation

Answer 5

ATP is produced by the direct transfer of a phosphate group from a phosphorylated substance

Question 6

What is Oxidative phosphorylation

Answer 6

ATP is produced from ADP and Pi as electrons are transferred along a series of carriers

Question 7

What are the 4 stages of Aerobic respiration in cells

Answer 7

Glycolysis
Link reaction
Kerbs Cycle
Electron transport chain

Question 8

What is glycolysis, and where does it occur

Answer 8

The splitting of glucose in a metabolic pathway that has four major steps, that takes place in the cytoplasm

Question 9

What is required in Glycolysis, and what is produced

Answer 9

Requires ATP, ADP, Pi and NAD
Produces NADH and ATP

Question 10

What is the process of activation in glycolysis

Answer 10

Glucose enters, and is phosphorylised to fructose bisphosphate, by ATP which changes to ADP

Question 11

What follows phosphorylation in glycolysis

Answer 11

The 6C fructose bisphosphate splits into 2 3C trips phosphate, which is then oxidised through loss of hydrogen atoms to form pyruvate

Question 12

What collects hydrogen atoms in Glycolysis

Answer 12

NAD which is reduced to form NADH

Question 13

What is the net gain of ATP in glycolysis, and how does this occur

Answer 13

Net gain of 2, as both triose phosphate molecules produce two ATP molecules each

Question 14

What is the Link reaction and where does it occur

Answer 14

The removal of hydrogen and carbon dioxide from pyruvate with the formation of an acetyl group, in the mitochondrial matrix

Question 15

What is the process of the Link reaction

Answer 15

Carbon dioxide diffuses out of the mitochondria and out of the cell. The hydrogen that is removed is picked up by NAD forming NADH. The 2C acetyl group is carried by conenzyme A, to produced Acetyl CoA

Question 16

What are examples of conenzymes carrying product of respiration elsewhere

Answer 16

NAD carries hydrogen to be used in the electron transport chain
Coenzyme A carries the acetyl group to be used in the Krebs cycle

Question 17

What is the Krebs cycle and where does it occur

Answer 17

The acetyl group, from acetyl CoA, combined with a 4C acid to form a 6C acid in the mitochondrial matrix

Question 18

What are the major steps in the Krebs cycle

Answer 18

2C acetyl CoA combined with the 4C acid to produce a 6C acid
Decarboxylation of the 6C acid results in the formation of the 5C acid
Decarboxylation of the 5C acid results in the formation of the 4C acid
At 3 points, hydrogen is released to reduce NAD to NADH
At 1 point, FAD is reduced to FADH2
One molecule of ATP is produced by the transfer of a phosphate group from an intermediate compound to ADP