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Flashcards in Mitochondria Deck (25)
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1
Q

Function of mitochondria

A

Oxidative phosphorylation (production of ATP through use of oxygen), Calcium sequestration, cell death, generate heat, organ-specific functions (urea cycle in the liver)

2
Q

Structure of mitchondria

A

Double lipid bilayer, innermembrane - convoluted structures - cristae, matrix (w/ ribosomes), outermembrane

3
Q

Inner membrane contains:

A

cristae, contains proteins for electron-transport, ATP synthase, transport proteins, but is impermeable to protein diffusion, because of large amounts of cardiolipin

4
Q

Matrix contains:

A

enzymes (TCA cycle), DNA, RNA, Ca++ granules, ribosomes

5
Q

Outer membrane contains:

A

Channel-forming protein (porin), is semipermiable, lipid synthesis enzymes

6
Q

Intermembrane space contains:

A

Enzymes that use ATP to phosphorylate nucleotides

7
Q

Staining of mitchondria

A

show up as striations, can use immunohistochemistry, enzyme histochemistry

8
Q

Oxidative phosphorylation definition

A

Oxidative because using oxygen as reactant to phosphorylate ADP to ATP

9
Q

Oxidative phosphorylation steps

A
  1. Pyruvate/FAs are transported into mitochondria from glycolysis and converted to acetyl CoA
  2. Acetyl CoA goes through the citric acid cycle in the matrix and produces NADH and CO2
  3. NADH is converted to NAD+ and e-
  4. e- move down electron transport chain the inner mitochondrial membrane with oxygen as the final e- acceptor becoming water, that simultaneously pushed H+ into the intermembrane space
  5. H+ flowing down its electrochemical gradient drives the production of ADP to ATP by ATP synthase
10
Q

Electron transport chain

A

Electron passed between different complexes in inner membrane

11
Q

Which has higher pH: inner membrane space or matrix?

A

Matrix because electron transport chain pumps H+ out

12
Q

Why do brown fat cells produce heat?

A

They uncouple ATPase and use H+ for lipid metabolism to make heat

13
Q

Metabolite transport

A

Carrier proteins that need energy, symporters driven by pH gradient and antiporters driven by voltage gradient

14
Q

Proteins targeted for matrix

A

TOM and TIM23, cleavable presequence

15
Q

Proteins targeted for inner membrane

A

TOM and TIM23, cleavable presequence AND ‘stop transfer’ sequence

16
Q

Proteins targeted for intermembrane space

A

TOM and TIM23, cleavable presequence AND inner membrane peptidase cleavage sequence

17
Q

What do chaperones do for proteins destined for the mitochondria

A

Keeps polypeptide in unfolded position until it gets to its final location

18
Q

Proteins w/out presequence

A

Some proteins lack presequence, but instead have noncleavable signals such as b-barrel proteins (porins), metabolite carrier proteins

19
Q

SAM complex

A

Important for proteins that need to stay in the outermembrane, such as porins, that go through TOM first and then are folded and then goes through SAM and into membrane

20
Q

TIM22 complex

A

Important for proteins that stay in the innermembrane, but that DONT have a cleavable presequence, that go through TOM first and then are folded and then goes through TIM22 and into membrane

21
Q

Chaperones use what form of energy

A

ATP and electrochemical gradient

22
Q

OXA translocase

A

Used for proteins synthesized in the mitochondria, presequence is not cleaved and protein is destined for inner membrane

23
Q

Ways to die when no ATP

A

Necrosis, causes inflammation

24
Q

Ways to die when ATP is available

A

Apoptosis, no inflammation

25
Q

Calcium and mitochondria

A

Calcium can trigger cascade of proteins leading to apoptosis