Mitochondria Flashcards Preview

M2M Unit IV HM > Mitochondria > Flashcards

Flashcards in Mitochondria Deck (21):
1

Principal sources of ATP

Fatty acids and glucose

2

Endosymbiont hypothesis

Inner mito mem is from bacteria, outer mem is from eukaryotic cell.
Mitochondria arose because of endocytosis of bacteria capable of oxidative phosphorylation.

3

Outer membrane

Semi-permeable

4

Inner membrane

less permeable, contains most of the machinery needed for oxidative phosphorylation.
Has cristae that increase SA.
Electron transfer.
Electrons from matrix are pumped across the inner mem.
Where ATP synthase is.

5

Matrix

Central space. Contains mito DNA. Has high proton gradient inside (outside is low)... nec. for ATPsynthase.

6

Where are mito proteins synthesized?

Majority in nucleus. Get into mito via TOM (passive. Translocase of outer mem) and TIM (ATP) (translocase of..)

7

Fission

Cell dividing into 2 parts that make new cells.
Required for mitophagy. Depends on GTPase. Uses Fis1 and Drp.

8

Fusion

GTPase. Mfn and OPA1.

9

Electron transfer

Mito electrons go from NADH to O2 to H20 during respiration.

10

NADH

Reducing enzyme. Holds the energy from glucose oxidation.

11

Mitochondria fx.

ATP generation, regulation of intracellular Ca, apoptosis.

12

Oxidative phosphorylation

Oxidation of nutrients to make ATP.
I. NADH-CoQ reductase
II. Succinate-CoQ reductase
III. CoQ-cytochrome c reductase
IV. Cytochrome c oxidase
The energy released by electrons flowing through electron transport chain is used to transport H+ across the inner mito mem (electron transport)
This generates potential energy in the form of a pH gradient and an electrical potential across this membrane.

13

ATP synthase

Makes ATP from ADP. ON INNER MEM.
Uses potential energy from electron transport chain... tapped by allowing H+ to flow back across the membrane down this gradient, through a large enzyme called ATP synthase; this process is known as chemiosmosis.
This rxn is driven by H+ flow, which forces rotation of a part of the enzyme; ATP synthase is a rotary mechanical motor.
2 main parts: F1 (enzyme that makes ATP) and is bound to F0 (inner mito mem proton channel).

14

How does ATP get out of mito

ATP-ADP antiporter

15

Mitochondria and cell damage

Cell damage --> Bak/Bax permeate outer mito mem --> cytochrome C released and binds cytoplasmic proteins to form --> apoptosome --> caspase activation --> death by apoptosis.

16

Mitochondria and ischemic damage

Mito can promote necrosis.
Ischemic injury --> MPTP dependent permeatio of inner/outer mito mem --> cytochrome release --> H+ gradient elimination --> blocked ATP production --> ATPsynthase converted to ATPase so use up available ATP ---> leads to ATP depletion and necrosis.

17

Why is mito quality controlled?

Damage mito can't produce ATP and produce lots of ROS, leads to cell damage and senescence by oxidating various cell proteins, lipids, DNA.

18

How is mito's quality controlled?

mito proteases (mAAA, iAAA, and Lon) recognize/degrade misfolded proteins.
Damaged mito can be "fixed" by fusing with healthy mito.
Really damaged ones eliminated with mitophagy.
Or can induce apoptosis.

19

Mutations in mito fusion machinery cause...?

AD optic atrophy
Charco-marie tooth type 2A

20

mutation in mAAA

hereditary spastic paraplegia

21

Arsenic

Inhibits oxidative phosphorylation and thus ATP production.