MBOD

Question 1

How many mitochondrial genes with known function are transcribed in the mitochondria?

Answer 1

13

Question 2

What percent of proteins found in the mitochondria are imported?

Answer 2

98%

Question 3

What do the mitochondrial genes encode?

Answer 3

oxphos subunit proteins

Question 4

What major protein is located in the outer mitochondrial membrane?

Answer 4

porin, a trimerizable protein

Question 5

What does porin do?

Answer 5

transports small (<5000Daltons) molecules between cell cytosol and intermembrane space

Question 6

What is the space between the outer and inner membranes called?

Answer 6

the intermembrane space

Question 7

What are the invaginations of inner membrane called?

Answer 7

cristae

Question 8

What connects the cristae to the inner membrane?

Answer 8

mitofilin

Question 9

What is cytochrome C, where is it located, and what does it do?

Answer 9

a mitochondrial carrier protein located near to the intermembrane space that functions to transport electrons between TM complexes of the inner membrane

Question 10

What are some proteins located in the inner mitochondrial membrane?

Answer 10

cardiolipin, electron transfer complexes, transporters/carriers

Question 11

What is cardiolipin?

Answer 11

important inner membrane protein associated with ETC complexes

Question 12

The inner mitochondrial membrane is permeable to what? impermeable to what?

Answer 12

permeable: H2O, O2, CO2
impermeable: protons, ions

Question 13

What is the morphology of cristae in a state of active respiration?

Answer 13

condensed

Question 14

What is the morphology of cristae in state 4 respiration?

Answer 14

condensed

Question 15

What is the morphology of cristae in state 3/inactive respiration?

Answer 15

expanded

Question 16

Why is the IM space expanded during active respiration?

Answer 16

it is full of protons (gradient) and thus has brought lots of water with it

Question 17

What are the main mitochondrial events leading up to apoptosis?

Answer 17

cristae fusion; cytochrome C released into cytosol; apoptosome formed in cytosol

Question 18

What is mitochondrial uncoupling?

Answer 18

It’s the uncoupling of mitochondria’s joint functions: consume O2 and produce ATP. Can occur when the proton gradient is lost

Question 19

What are the major mitochondrial metabolic functions?

Answer 19

TCA, ETC, Heme synthesis, DNA/RNA transcription, protein synthesis, ribosome assembly, beta-oxidation, urea cycle (ammonia), transport, Ca2+ uptake/release

Question 20

What are the 4 major ROS?

Answer 20

1. O2 (oxygen)
2. O2- (superoxide)
3. H2O2 (hydrogen peroxide)
4. *OH (hydroxyl radical)

Question 21

What is the cell’s protection against superoxide?

Answer 21

superoxide dismutase

Question 22

What is the cell’s protection against hydrogen peroxide?

Answer 22

catalase –> H2O + O2

Question 23

What is the cell’s protection against hydroxyl free radical?

Answer 23

vitamin C and E

Question 24

How does hydroxyl radical result?

Answer 24

reaction of Fe2+ with H2O2

Question 25

Where is a mitochondrial carrier located?

Answer 25

in the mitochondrial inner membrane

Question 26

How does the ATP/ADP mitochondrial carrier work?

Answer 26

binds ADP in IM space, everts, released ADP to matrix; binds ATP in matrix, everts, releases ATP to IM space

Question 27

How are mitochondrial carriers stabilizing when changing conformation?

Answer 27

charge pairs occur at membrane boundaries