Section 4- Respiration

Question 1

Describe and explain 3 ways in which mitochondria are adapted for respiration

Answer 1

• The inner mitochondrial membrane is folded into crtistae, which increases the membrane’s surface area
• There are lots of ATP Synthase molecules in the inner mitochondrial membrane to produce a lot of ATP in the final stage of respiration
• The mitochondrial matrix contains all the reactants and enzymes needed for the Krebs cycle to take place

Question 2

Where in the cell does glycolysis take place

Answer 2

Cytoplasm

Question 3

What is the ATP used for in glycolysis

Answer 3

To phosphorylate glucose making triose phosphate

Question 4

How is pyruvate transported into the mitochondria

Answer 4

Active Transport `

Question 5

Where in the mitochondria does the link reaction take place

Answer 5

mitochondrial matrix

Question 6

In the link reaction, pyruvate is converted into acetate. Describe how this happens

Answer 6

• Pyruvate is decarboxylated to form carbon dioxide
• NAD is reduced by collecting a hydrogen from pyruvate
• acetate formed

Question 7

What is the role of coenzyme A in the Link Reaction

Answer 7

• Co A combines with acetate to form acetyl co enzyme A

- NADH is used in oxidative phosphorylation

Question 8

What happens to the products of the link reaction

Answer 8

Acetyl Co A enters krebs cycle
NADH enters oxidative phosphorylation
carbon dioxide is released as a waste gas

Question 9

what is the name of the process that converts ADP and an intermediate to ATP in the Krebs cycle

Answer 9

substrate level phosphorylation

Question 10

During Oxidative Phosphorylation, what happens to the electrons as they move down the electron transport chain

Answer 10

They lose energy

Question 11

Give three reasons why the actual yield of ATP from aerobic respiration is less than the predicted theoretical yield

Answer 11

• Some NADH is used for other reactions other than oxidative phosphorylation
• Some ATP is used up actively transporting substances into the mitochondria
• Inner mitochondrial membrane is leaky so some protons may leak into the matrix without passing through ATP Synthase and therefore not making ATP

Question 12

In a respirometer, what is the function of the potassium hydroxide solution

Answer 12

It absorbs carbon dioxide

Question 13

What is the chemiostatic theory

Answer 13

The theory that energy lost from electrons moving down the electron transport chain creates a proton gradient which is then used to synthesise ATP

Question 14

Where in the cell does anaerobic respiration take place

Answer 14

cytoplasm

Question 15

In which organisms does lactate fermentation take place

Answer 15

mammals and some bacteria

Question 16

Describe what happens to pyruvate in lactate fermentation

Answer 16

-NADH transfers hydrogen to pyruvate to make lactate and ATP

Question 17

Describe what happens to ethanal in alcoholic fermentation

Answer 17

-NADH transfers hydrogen to ethanal to make ethanol and ATP

Question 18

What is a respiratory substrate

Answer 18

Any biological molecule that can be broken down in respiration to release energy