EXAM 3 Lec 13

Question 1

electron transport chain (ETC)

Answer 1

has mobile electron carriers linking trans-membrane complexes that make a proton gradient

Question 2

what is the proton gradient used for in the ETC

Answer 2

to make ATP

Question 3

electrochemical gradient

Answer 3

formed by energy released as electrons flow along ETC

Question 4

what is an orbit

Answer 4

an electron in an atom has a specific level of energy that can increase or decrease a specific amount of energy

Question 5

function of a pathway of proteins and compounds

Answer 5

can pass an electron along and capture its orbital energy

Question 6

what is the cristae

Answer 6

the inner mitochondrial membrane

Question 7

where is the ER in association to mitochondria

Answer 7

the ER is proximal to mitochondria but separate

there is a lipid shuttle between the two

Question 8

mitochondrial physical ETC

Answer 8

3 transmembrane protein complexes use electron energy to pump proton into the intermembrane space

Question 9

ubiquinone

Answer 9

a membrane bound mobile carrier transfers electrons from complex 1 to complex 3

Question 10

cytochrome c

Answer 10

a water-soluble mobile carrier shuttles electrons from complex 3 to complex 5

Question 11

what is the terminal acceptor of electron flow

Answer 11

oxygen, which generates H2O

Question 12

mitochondrion NADH

Answer 12

has a covalently bound hydrogen which is released as a hydride ion composed of a proton and two high energy electrons
high energy electrons are taken up by the ETC and the proton is released into the intermembrane space

Question 13

chloroplasts have 3 independent membranes

Answer 13

double membrane (outer and inner) defines an intermembrane space, the inner membrane defines the interior stroma

Question 14

characteristics of the stroma

Answer 14

the stroma has independent membrane vesicles (thylakoids) usually stacked like pancakes (grana, granum)

Question 15

purpose of the single membrane of thylakoids

Answer 15

defines internal lumen where protons are pumped into by photosynthesis electron transport

Question 16

stage one of photosynthesis

Answer 16

light reactions
photon of light energy is absorbed with energy shifting an electron into a more energetic orbital
electron energy is captured in an ETC to produce ATP and NADPH

Question 17

stage two of photosynthesis

Answer 17

dark reactions

inorganic CO2 fixed into glyceraldehyde-3-phosphate, which is exported to the cytosol

Question 18

antenna complex

Answer 18

chlorophyll pigments in the thylakoid membrane
can absorb photons of particular wavelengths
photon of light energy absorbed with energy shifting an electron into a more energetic orbital

Question 19

light energy recapture

Answer 19

reaction center chlorophylls transfer their electrons to electron carrier proteins. PSII electrons replaced from water splitting. PSI electrons from plastocyanin

Question 20

where do protons accumulate in light-dependent reactions

Answer 20

on the lumen side of the thylakoid relative to the stromal side

Question 21

chemiosmotic coupling

Answer 21

electron energy from electromagnetic radiation or high energy carriers NADH, is released stepwise and captured in protein complexes
captured energy pump hydrogen ions across a membrane to create a H+ gradient
energy from H+ flows through an ATP synthase enzyme complex to drive ATP formation from ADP + phosphate

Question 22

where does chemiosmotic coupling occur

Answer 22

on the prokaryotic cell membrane or eukaryotic mitochondrial inner membrane

Question 23

potential energy of the mitochondrial ETC

Answer 23

protons accumulating in the intermembrane space creates a large positive charge different and a H+ gradient (pH difference)
AKA proton motive force

Question 24

function of the proton motive force in the mitochondrial ETC

Answer 24

moves protons (H+) back into the matrix coupled with ATP production from ADP and Pi