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Flashcards in Mitochondria Deck (41):
1

The number of mitochondria in healthy cells varies from

200-10,000

2

Liver cells have how many mitochondria?

~1000

3

Muscle is a syncytium, meaning

a fused series of cells with thousands of mitochondria

4

What is the evolutionary nature of mitochondria?

Endosymbiotic bacteria that were incorporated into eukaryotes 2 billion years ago

5

Acetyl-coA is produced from

pyruvate or fatty acid oxidation (both in mitochondria)

6

What are the processes carried out by mitochondria?

Acetyl-coA production from pyruvate or fatty acid oxidation, ketone body synthesis (from Acetyl-coA via HMG-coA), TCA cycle, and oxidative phosphorylation

7

Ketone body synthesis

primary fuel in starvation; metabolite products of fatty acids (acetoacetate, d-B-hydroxybutyrate, acetone)

8

Fatty acid oxidation occurs where?

occurs in mitochondria, produces Acetyl-coA from fatty acids eg palmitic acid (16c) produces 8 AcoAs for TCA cycle

9

Reactive oxygen species

are created when e- leak from the ETC; they degrade and destroy mitochondria and other cell components

10

Mitochondria produce high yields of ATP by

oxidation of fuels (pyruvate or fat) to CO2

11

What cells in the body lack mitochondria?

red blood cells and retina cells - they are obligated to anaerobic metabolism producing lactate

12

Ageing can be attributed to

loss of mitochondria and damage by ROS

13

Mitochondrial diseases are attributed to

mutations in mitochondrial or nuclear DNA

14

What is the pathological appearance of mitochondrial disease?

ragged red fibres

15

What are ragged red fibres?

hallmark of mitochondrial disorders; red subsarcolemmal deposits in sections of muscle stained with Gomori trichome

16

Adipose tissue is signalled to release fatty acids by

adrenaline (FoF) or glucagon

17

Palmitic acid metabolism yields how many ATP?

~108

18

What is the role of the urea cycle?

metabolism of nitrogen (NH3) from proteins (amino acids) to urea - occurs in mitochondria

19

How many grams of protein are required daily?

100g

20

Adipose tissue releases what in response to adrenaline or glucagon?

glycerol for gluconeogenesis and trigylcerides (FFA) for beta-oxidation in mitochondria

21

The outer membrane of mitochondria is permeable to

small molecules

22

The inner membrane of mitochondria is permeable to

nothing without a transporter

23

Pyruvate enters the inner mitochondrial membrane via

antiport with OH- or symport with H+

24

Pyruvate is converted to acetyl-coA by

pyruvate dehydrogenase

25

Each turn of the TCA cycle produces

3NADH, 1FADH2, 1GTP (ATP)

26

Oxidative phosphorylation occurs at

the inner mitochondrial membrane

27

Ubiquinone =

Q = coenzyme Q = Q10 = coQ10

28

What does ATP synthase (ETC) require to function?

an in-tact inner mitochondrial membrane; if the membrane is broken it becomes an ATPase

29

mtDNA mutations do not affect which respiratory complex?

II - it is encoded on nuclear DNA

30

How many H+ are pumped per mol NADH?

10 (200kJ/mol)

31

How many H+ are pumped per mol FADH2?

6 (enters at complex II)

32

How does ATP synthase generate ATP?

H+ enters the c10 subunit and via charge separations rotates the gamma subunit; this triggers each beta subunit to make ATP from ADP + Pi

33

What is the role of superoxide dismutase?

generates hydrogen peroxide (H2O2) from O2 radicals which is converted to water by glutathione peroxidase - protective mechanism against ROS

34

What is uncoupling of oxidative phosphorylation??

leaking of the membrane (eg caused by dinitrophenol) allows H+ to leak out without ATP production - the chain oxidizes NADH but produces no ATP

35

NADH generates how many ATP?

2.5

36

FADH2 generates how many ATP?

1.5

37

Glucose generates how many ATP?

32

38

What is the function of the malate-aspartate shuttle?

transfers the reducing power of NADH from cytosol to mitochondria for oxidative phosphorylation; generates 32 ATP per glucose

39

What is the function of the glycerol-3-phosphate shuttle?

operates in muscle, dumps reducing power of NADH right into complex II via FADH2; generates 30 ATP per glucose

40

Malate-aspartate shuttle results in how many ATP per glucose?

32

41

Glycerol-3-phosphate shuttle results in how many ATP per glucose?

30