Link Reaction 18.2

Question 1

Name the main parts of the mitochondria

Answer 1

• Outer mitochondrial membrane
• Intermembrane space
• Inner mitochondrial membrane
• Cristae
• Matrix

Question 2

Outer mitochondrial membrane

Answer 2

Separates contents of mitochondria from the rest of the cell so that it is the optimum conditions for respiration

Question 3

Intermembrane space

Answer 3

The electron transport chain pumps protons into here. The space is small so that the concentration builds up quickly

Question 4

Inner mitochondrial membrane

Answer 4

This is where the electron transport chain is located and it contains hydrophilic membrane channels

Question 5

Matrix

Answer 5

Contains mitochondrial DNA and many enzymes for the Krebs cycle and link reactions

Question 6

Cristae

Answer 6

Projections of the inner mitochondrial membrane that increases surface area for oxidative phosphorylation

Question 7

Where does the link reaction occur?

Answer 7

In the mitochondrial matrix

Question 8

What is needed for the link reaction to occur?

Answer 8

ATP and oxygen

Question 9

Describe what happens during the Link reaction

Answer 9

Pyruvate is actively transported from the cytoplasm to the mitochondrial matrix which is why ATP and oxygen are needed.

• Pyruvate is oxidised by NAD+ which becomes NADH
• It then has a carbon dioxide removed which is called decarboxylation and an acetyl group is formed ( 2 carbons).
• The Co2 is removed as waste
• The acetyl group is combined with coenzyme A to form acetyl CoA which is used later.

Question 10

What is the role of NAD?

Answer 10

It is a coenzyme that carries hydrogens and uses them and accepts them to take part in redox reactions. The enzyme it assists is dehydrogenase enzyme

Question 11

Why does glycolysis not occur in the mitochondria?

Answer 11

• Glucose too big move into the mitochondria
• Inorganic phosphate ions are needed from the cytoplasm
• No transport proteins for pyruvate in the mitochondria