Mitochondria- energy production

Question 1

what is the largest organelles?

Answer 1

mitochondria

Question 2

how are mitochondria usually depicted (in shape and size)?

Answer 2

Usually depicted as cylinders around 0.5 – 1 mm in diameter and up to 7 mm long

Question 3

how many mitochondria are in the typical cell?

Answer 3

200

Question 4

how many mitochondria are found in a liver cell?

Answer 4

1000-2000 (20% of the total cell volume)

Question 5

how many mitochondria are in skeletal muscle (in athletes)?

Answer 5

4000

Question 6

what are 2 types of cells that have less than average number of mitochondria?

Answer 6

• skin cells
• fat cells

Question 7

explain the inner membrane of a mitochondria (three things)

Answer 7

• highly specialised lipid bilayer
• particularly impermeable to ions
• the site of the electron transport chain and ATP synthesis.

Question 8

what do the 2 highly specialised membrane create?

Answer 8

creates an intermembrane space and the internal matrix

Question 9

what are the fold in the inner membrane called? function?

Answer 9

• cristae
• serve to greatly increase the surface area of the inner membrane

Question 10

what does the matrix of a mitochondria contain?

Answer 10

enzymes that metabolise pyruvate and fatty acids to produce acetyl CoA and also enzymes that oxidise acetyl CoA in the citric acid cycle

Question 11

what is glycolysis?

Answer 11

• Glucose can be metabolised through oxidation to produce energy
• These reactions occur in the cytosol.

Question 12

how many molecules of ATP are produced from 1 molecule of glucose?

Answer 12

• Yields a net production of 2 ATP molecules.
• Under aerobic conditions this can increase to 4 ATP molecules.

Question 13

where does the citric acid cycle occur? what does it produce?

Answer 13

• occurs in the mitochondrial matrix
• produces reduced electron carriers (e.g. NADH) for the electron transport chain.

Question 14

what is the electron transport chain’s function?

Answer 14

is to break the large free-energy drop from food to O2 into smaller steps that release energy in manageable amounts

Question 15

what takes up around 90% of the total oxygen uptake in most cells?

Answer 15

cytochrome oxidase complex

Question 16

what are uncoupling proteins?

Answer 16

• Mitochondrial transporters present in the inner membrane of mitochondria.
• They are found in all mammals and in plants.