Mitochondria and Peroxisomes

Question 1

What is the function of the mitochondria?

Answer 1

It is known as the powerhouse of the cell.

Energy production from the oxidation of glucose substances / release ATP / Apoptosis / Thermogenesis.

Question 2

What does the F0 and F1 section of the mitochondria represent?

Answer 2

Represents the ATPase enzyme.

Question 3

Why does mitochondria have microtubules?

Answer 3

Aids diffusion of substances.

Question 4

What is a key feature that allows mitochondria to change shape and size?

Answer 4

Plasticity.

Question 5

During which processes does mitochondrial morphology changes occur?

Answer 5

Apoptosis
Ca2+ transfer
Cell Cycle
Nutrient Starvation

Question 6

What is the genome of mitochondria like?

Answer 6

Mitochondrial chromosome is circular and NOT enveloped. I is also not packaged into chromatin.

Question 7

Where is the genome of the mitochondria usually found?

Answer 7

Usually present in the matrix.

Question 8

Where is mtDNA normally found?

Answer 8

Hair
Bones
Teeth

Question 9

Who is mitochondrial genes inherited from?

Answer 9

The mother’s side.

Therefore, if the mum has a mutation in the mitochondrial DNA the mutation is passed onto the child.

Question 10

What is the size of the small mitochondrial ribosome?

Answer 10

28S

Question 11

What is the size of the large mitochondrial ribosome?

Answer 11

39S

Question 12

What is the purpose of the mitochondria during ATP production?

Answer 12

Produces ATP via the usage of oxygen and energy stored in the food.

Question 13

What does the breakdown of fatty acids by the mitochondria result in?

Answer 13

Produces acetyl CoA.

Question 14

Where does mitochondria localise?

Answer 14

Near sites of high ATP utilisation and demand.

Question 15

What are the main causes of mitochondrial disease?

Answer 15

Defects of mitochondrial DNA and mitochondrial translation.

Question 16

Explain what the Leigh Syndrome is.

Answer 16

This is a neurometabolic disorder which affects the CNS.

Question 17

Why does Leigh Syndrome occur?

Answer 17

Mutation in the MT - ATP6 gene - this encodes for the ATP synthase.

Question 18

What is a peroxisomes?

Answer 18

Ubiquitous single - membrane bound organelles.

Question 19

What does ubiquitous mean?

Answer 19

Appears everywhere.

Question 20

What does peroxisomes NOT contain?

Answer 20

DNA or Ribosomes.

Question 21

What does peroxisomes CONTAIN?

Answer 21

Contains digestive enzymes which use molecular oxygen to OXIDISE various substrates.

Question 22

Where are peroxisomal proteins normally found?

Answer 22

Encoded within the nucleus / translated in the cytoplasm and then imported.

Question 23

How does peroxisomes replicate?

Answer 23

Self - replicating via the process of fission.

Question 24

What does the process of fission allow?

Answer 24

Splits the peroxisome to split into 2 daughter cells.

Question 25

What is the main function of peroxisomes?

Answer 25

The enzymes use oxygen in order to convert certain substances into peroxide.
Convert the peroxide into water by ENZYME CATALASE.

Question 26

What enzymes does peroxisomes contain?

Answer 26

Oxidative enzymes = D - amino acid oxidase / grate oxidase / catalase / lysosomes digestive enzymes.

Question 27

What is the function of peroxisomes in terms of metabolism?

Answer 27

Metabolism of very long chain fatty acids / branched chain fatty acids / D - amino acids and polyamines.

Question 28

What function does peroxisomes play in synthesis?

Answer 28

Certain lipids like cholesterol and plasmoalogens are synthesised.

Question 29

What function does peroxisomes play in breakdowns?

Answer 29

Breaks down excess purines to uric acid.

Question 30

How does peroxisomes communicate physically?

Answer 30

Vesicles transport and by biological messengers.

Question 31

What are some of the metabolic processes peroxisomes are part of?

Answer 31

Beta - oxidation of fatty acids / bile acid synthesis / maintenance of cellular ROS homeostasis.