Mitochondria

Question 1

What size is a mitochondria?

Answer 1

1-10um

Question 2

What are the functions of the mitochondria?

Answer 2

-Cell signalling
-Cell differentiation
-Cell death
-Control of cell cycle and growth

Question 3

What is needed to neutralise a molecule of ATP?

Answer 3

2 molecules of magnesium

Question 4

Where is mitochondria localised?

Answer 4

-Aerobic eukaryotic cells

Question 5

Where do mitochondria cluster in the body?

Answer 5

-Regions of greatest metabolic activity, e.g. greatest muscle groups

Question 6

What is the name of the theory of how mitochondria arise?

Answer 6

Endosymbiotic theory

Question 7

What does the endosymbiotic theory state?

Answer 7

Mitochondria are descended from ancient bacteria, which were engulfed by the ancestors of eukaryotic cells

Question 8

How many types of mitochondrial proteins do humans have?

Answer 8

614

Question 9

When do mitochondrial proteins increase in numbers?

Answer 9

At times when more energy is needed

Question 10

What is the role of the outer membrane of the mitochondria?

Answer 10

Encloses the organelle

Question 11

What is the protein to phospholipid ratio in the outer membrane of the mitochondria?

Answer 11

1:1

Question 12

What is the name of the large proteins in the outer membrane?

Answer 12

Porins

Question 13

What is the role of porins in the outer membrane?

Answer 13

Controls the size of proteins that can pass through the membrane

Question 14

How can larger proteins enter the outer membrane of the mitochondria?

Answer 14

They have a signalling sequence to utilise active transport called a translocase

Question 15

What can disruption of the outer membrane of the mitochondria lead to?

Answer 15

Proteins leak into the cytosol and larger molecules enter leading to cell death

Question 16

What is the intermembrane space of the mitochondria?

Answer 16

Space between the outer membrane and inner membrane

Question 17

What is the name of the protein that is located in the intermembrane space?

Answer 17

Cytochrome c

Question 18

What are the functions of proteins in the mitochondria?

Answer 18

-Redox reactions of oxidative phosphorylation
-ATP synthase
-Transport proteins

Question 19

Where does ATP synthesis occur?

Answer 19

Matrix

Question 20

What is the role of transport proteins?

Answer 20

Regulates metabolite passage in and out of the matrix

Question 21

What is ATP synthase?

Answer 21

The enzyme that synthesises ATP from ADP and phosphate group

Question 22

What does the inner membrane consist of?

Answer 22

A high protein-to-phospholipid ratio, 3:1

Question 23

What phospholipid is the inner membrane rich in?

Answer 23

Cardiolipin

Question 24

What is unusual about cardiolipin

Answer 24

has 4 fatty acids rather than 2, helps make membrane impermeable

Question 25

What is the cristae of the mitochondria?

Answer 25

Invaginations of the inner membrane

Question 26

What is the role of the cristae?

Answer 26

Increases surface area of inner membrane

Question 27

What does an increased surface area of the inner membrane aid?

Answer 27

ATP production

Question 28

What is the new theory for the shape of mitochondria organelles?

Answer 28

Extensively branched -Fewer -Larger size

Question 29

What is the mitochondrial matrix?

Answer 29

The space enclosed within the inner membrane

Question 30

What is contained in the matrix?

Answer 30

-2/3 of proteins -Enzymes -Mitochondrial ribosomes -tRNA

Question 31

What are the functions of the enzymes in the matrix?

Answer 31

-Oxidation of pyruvate and fatty acids -Krebs cycle

Question 32

What metabolic functions occur in the outer membrane?

Answer 32

-Phospholipid synthesis -Fatty acid desaturation -Fatty acid elongation

Question 33

What metabolic functions occur in the inner membrane?

Answer 33

-Electron transport -Oxidative phosphorylation -Pyruvate import -Fatty acyl CoA import -Metabolite transport

Question 34

What metabolic functions occur in the matrix?

Answer 34

-Pyruvate oxidation -TCA cycle -DNA replication -RNA synthesis -Protein synthesis

Question 35

What is the role of mitochondrial DNA?

Answer 35

Codes for most proteins genes for RNA, tRNA and protein coding regions

Question 36

What are mitochondrial diseases?

Answer 36

Genetic defects of muscle or nerve tissue

Question 37

What are the results of severe mitochondrial diseases?

Answer 37

-Infant death -Blindness -Deafness -Seizures

Question 38

What are the results of milder mitochondrial diseases?

Answer 38

-Muscle weakness -Intolerance to exercise -Infertility

Question 39

Where do most defects in mitochondrial DNA occur?

Answer 39

In genes coding for mitochondrial tRNA

Question 40

How do mitochondrial diseases arise?

Answer 40

When most of mitochondria in a tissue have a certain mutant gene