Biochemistry (Test 4-Final Exam)

Front 1

what three things occur in the mitochondrial electron transport chain?

Back 1

1. e- transferred and NADH and FADH2 are reoxidized to NAD+ and FAD so they can participate in additional substrate oxidation reactions

2. the transferred e's participate in the sequential redox reactions of multiple redox centers

3. during e- transfer, protons are expelled from the mitochondrion creating a proton gradient across mitochondrial membrane

pg. 597

Front 2

what is the site of eukaryotic oxidative metabolism ?

Back 2

the mitochondrion

Front 3

what organelle contains pyruvate dehydrogenase, the citric acid cycle enzymes, the enzymes catalyzing fatty acid oxidation, and the enzymes and redox proteins involved in electron transport and oxidative phosphorylation?

Back 3

the mitochondria

Front 4

the number of cristae in a mitochondria represent what?

Back 4

the respiratory activity of the cell

Front 5

is the inner or outer membrane of the mitochondria richer is protein?

Back 5

inner

Front 6

where are electrons transporters located? what do they do?

Back 6

in the inner mitochondrial membrane -they ferry electrons from NADH and FADH2 to O2

Front 7

what are the inhibitors used to study the etc?

Back 7

-rotenone (plant toxin)
-amytal (barbiturate)
-antimycin A (antibiotic)
-cyanide

Front 8

where do amytal and rotenone inhibit the ETC?

Back 8

complex I

Front 9

where does antimycin A inhibit the ETC?

Back 9

complex III

Front 10

where does CN- inhibit the ETC?

Back 10

complex IV

Front 11

what is complex I ?

Back 11

NADH-Coezyme Q oxioreductase

(passes e- to CoQ)

Front 12

what coenzymes does complex I contain?

Back 12

flavin mononucleotide (FMN) & iron-sulfer clusters

Front 13

in complex I how many electrons are capable of being accepted/donated by FMN and CoQ?

Back 13

1 or 2 -because their semiquinone forms are stable

Front 14

complex I and complex II of the e- transport chain both accomplish what?

Back 14

the transfer of electrons to CoQ from reduced substrates (NADH or succinate)

Front 15

what is complex II AKA?

Back 15

succinate-coenzyme Q oxidoreductase

(passes E- from succinate to CoQ)

Front 16

what is complex III AKA?

Back 16

coenzyme Q-cytochrome c oxidoreductase or cytochrome bc1

(passes electrons from reduced CoQ to cytochrome c)

Front 17

what does complex III contain?

Back 17

two b-type cytochromes
one cytochrome c1
one iron cluster associated with two his residues (Rieske Center)

Front 18

what is the Q-cycle?

Back 18

bifurication of the flow of electrons from CoQH2, to cytochrome c1 and to cytochrome b -permits complex III to pump protons from the matrix to the intermembrane space.

Front 19

what is cytochrome C oxidase?

Back 19

complex IV

(catalyzes the one-electron oxidations of four consecutive reduced cytochrome c molecules and the concomitant four-electron reduction of on 02 molecule)

Front 20

complex 4 contains what redox centers?

Back 20

-cytochrome a
-cytochrome a3
-Cub (copper atom)
-CuA center (pair of copper atoms)

Front 21

Complex IV reduces O2 to 2 H20 using 4 electrons from 4 ________ and 4 protons from the matrix.

2 protons are translocated to the intermembrane space for every __ electron(s) that reduce oxygen.

Back 21

Complex IV reduces O2 to 2 H20 using 4 electrons from 4 cytochrome c and 4 protons from the matrix.

2 protons are translocated to the intermembrane space for every 2 electrons that reduce oxygen.

Front 22

which theory explains that protons translocated into the intermembrane space during ET through complexes I, III and IV establish an electrochemical gradient across the inner mitochondrial membrane?

Back 22

chemiosmotic theory

Front 23

how is ATP coupled to electron transport?

Back 23

through the formation of a transmembrane proton gradient during electron transport by complexes I, III and IV.

Front 24

what does the p/o ratio do?

Back 24

Relates the moles of ATP produced to the moles of O reduced

Front 25

what does 2,4-DNP do?

Back 25

uncouples ETC and ATP synthesis

Front 26

what does the existence of a proton gradient depend on?

Back 26

the impermeability of the membrane

Front 27

what do uncouplers do?

Back 27

make the membrane permeable for protons, thereby dissipating the gradient

Front 28

complex 5 is AKA?

Back 28

the phosphorylation complex

Front 29

the affinity of the binding -change mechanism is determined by what?

Back 29

the position of the central stalk

Front 30

photosynthesis is essentially the reduction of what?

Back 30

carbon

Front 31

what occurs during light rxn of photosynthesis?

Back 31

specialized pigment molecules capture light energy and are oxidized

ultimately, NADP+ is reduced to NADPH

Front 32

what occurs during dark rxn of photosynthesis?

Back 32

NADPH and ATP are used to reduce CO2 and incorporate it into the 3-carbon GAP molecule

Front 33

a complex of antenna pigments is called what?

Back 33

light-harvesting complex

Front 34

what is the most common accessory pigment?

Back 34

b-carotene

Front 35

what is the z-scheme?

Back 35

the way in which various prosthetic groups of the photosynthetic apparatus of plants are arranged -based on electrons flowing from low to high reduction potential!

Front 36

what is PbRC?

Back 36

the reaction center involved in purple photosynthetic bacteria

it is a transmembrane protein

Front 37

how is oxygen generated in photosynthesis?

Back 37

by OEC of light rxn PSII

Front 38

what catalyzes CO2 fixation?

Back 38

ribulose bisphosphate carboxylase

Front 39

what happens to electrons released by the photooxidation of PSII ?

Back 39

they're transferred via plastoquinone to the cytochrome b6f complex.