SFP: mitochondria

Question 1

name the major structural components of mitochondria

Answer 1

outer membrane, inner membrane, inter-membrane space, matrix

Question 2

describe the outer membrane

Answer 2

it contains porins, making it permeable to small molecules

Question 3

describe the inner membrane

Answer 3

folded into cristae that contain ETC and ATP synthase. these help maintain the protein gradient

Question 4

describe the matrix

Answer 4

has enzymes for TCA cycle and FA oxidation; also contains mitochondrias DNA< ribosomes, tRNAs, and calcium

Question 5

what determines the concentration of mitochondria in a cell

Answer 5

the cells energy needs! cardiac muscle for example will have a lot of mitochondria

Question 6

what is the general shape of cristae?

Answer 6

lamellar; steroid hormones have tubular ones. the length of cristae is related to how active and energy producing they are

Question 7

how are mitochondria able to move

Answer 7

traveling along microtubules

Question 8

what kind of issues are linked to problems with mitochondrial division?

Answer 8

diabetes and neurodegenerative disease

Question 9

what is the presequence pathway

Answer 9

delivers matrix proteins and some inner membrane proteins

Question 10

what are Tom and tim?

Answer 10

tom: translocase of the outer membrane
tim: translocase of the inner membrane

Question 11

what is a presequence

Answer 11

a specific AA sequence that directs the protein to the mitochondria

Question 12

what is an internal sequence

Answer 12

a hydrophobic targeting sequence that allows proteins to exit tim laterally to be inserted into the inner membrane

Question 13

what are heat shock proteins

Answer 13

chaperones that protect proteins from degradation and help them fold

Question 14

what is a matrix processing peptidase

Answer 14

enzyme in the matrix that snips off the presequence to allow for proper folding of a protein

Question 15

describe the presequence pathway

Answer 15

• proteins are targeted to the outer mitochondrial membrane by binding of the presequence to tom
• protein passes through tom and inter the intermembrane space
• protein passes through tim in the inner membrane. process is driven by a gradient attracting positive charges
• if the protein has an internal sequence it will move laterally into the inner membrane. if not it enters the matrix.
• once in the matrix, the protein is driven into the mitochondria via a heat shock protein
• presequence is cleaved off. protein is folded.

Question 16

describe the insertion of proteins into the outer membrane

Answer 16

• synthesized porin goes through tom
• tiny tim shuttle the porin to the SAM complex
• SAM complex inserts the porin

Question 17

what are beta barrels

Answer 17

the porins on the outer membrane; often called VDAC. they transport small hydrophilic molecules like ATP, ADP, pyruvate

Question 18

what is CPT1

Answer 18

enzyme that transports long chain FA into the intermembrane space from the cytosol

Question 19

the inner membrane of the mitochondria is ___ to ATP, ADP, FA, Pi

Answer 19

impermeable

Question 20

what is ANT?

Answer 20

transports one ATP out of the matrix in exchange for ADP from the intermembrane space

Question 21

what is a Pi symporter

Answer 21

brings Pi and H into the matrix

Question 22

what is a. pyruvate symporter

Answer 22

brings pyruvate and H into the membrane

Question 23

what is a calcium uniporter

Answer 23

brings calcium into the matrix

Question 24

what is CPT II

Answer 24

trantsports FAs from the intermembrane space into the matrix

Question 25

main components in the outer membrane

Answer 25

VDAC, TOM, CPT I

Question 26

main components in the inner membrane

Answer 26

TIM, ANT, CPTII, pyruvate symporter, Pi symporter, calcium uniporter

Question 27

main components on the cristae

Answer 27

ETC, ATP synthase

Question 28

what are peroxisomes

Answer 28

membrane bound organelles that contain a bunch of enzymes. they are oxidative enzymes that generate a lot of peroxide.

Question 29

what do catalases do

Answer 29

break down the peroxide produced by peroxisomes

Question 30

what is the function of peroxisomes

Answer 30

oxidating fatty acids, synthesizing lipids, synthesizing bile acids, synthesizes phospholipids