ENERGY METABOLISM I AND II

Question 1

removal of electrons

Answer 1

oxidation

Question 2

gain of electrons

Answer 2

reduction

Question 3

oxidizes a reduced substrate
also called oxidant; electron acceptor
must be in the oxidized state
converted to the reduced form

Answer 3

oxidizing agent

Question 4

reduces an oxidized substrate; also called reductant
electron donor
must be in the reduced state
converted to the oxidized state

Answer 4

reducing agent

Question 5

measures the tendency of a biologic system to release or accept electrons

Answer 5

standard redox potential

Question 6

enzymes involved in oxidation and reduction

Answer 6

oxidoreductases

Question 7

4 groups of oxidoreductases

Answer 7

oxidases, dehydrogenases, hydroperoxidase, oxygenase

Question 8

transfers electrons directly to oxygen

catalyze removal of hydrogen from a substrate by using oxygen as a hydrogen receptor

forms water or hydrogen peroxide

examples include: flavin mononucleotide

Answer 8

oxidase

Question 9

it is a hemoprotein

contains 2 hemes (2 Fe)

terminal component of the ETC

inhibited by carbon monoxide, cyanide, and hydrogen sulfide

Answer 9

cytochrome oxidase

Question 10

contains flavin mononucleotide or flavin dinucleotide as prosthetic groups

derivatives of vitamin B2 or flavoprotein

Answer 10

flavoprotein oxidases

Question 11

enzyme found in the kidney, oxidative deamination of naturally occuring amino acids

flavoprotein oxidase

Answer 11

l-amino acid oxidase

Question 12

contains metals as essential cofactors

ex. xanthine oxidase, FMN linked (contains molybdenum)

Answer 12

metalloflavoproteins

Question 13

transfer of hydrogen from one substrate to another in a coupled oxidation-reduction reaction

transfers electrons in the electron transport chain

Answer 13

dehydrogenases

Question 14

3 types of dehydrogenases

Answer 14

pyridine linked dehydrogenases
flavin linked dehydrogenases
cytochrome b,c1, c , a

Question 15

use derivatives of of niacin as coenzymes

examples:NAD+ and NADP-linked dehydrogenase

Answer 15

pyridine linked dehydrogenase

Question 16

involved in oxidative pathways of metabolism that generates ATP

ex: glycolysis, Kreb’s cycle, and ETC

Answer 16

NAD linked dehydrogenase

Question 17

involved in reductive synthesis

examples fatty acid and steroid synthesis

Answer 17

NADP linked dehydrogenase

Question 18

FMN and FAD are more tightly bound

derivatives of vitamin B2 or riboflavin

involved in electron transport chain and therefore ATP generation

examples NADH, succinate, and fatty acyl-CoA dehydrogenases

Answer 18

flavin linked dehydrogenases

Question 19

derived from Niacine (Vit. B3)
active portion is the nicotinamide ring
carries 2 electrons but only 1 H+
NADH+H

Answer 19

NAD

Question 20

derived from Riboflavin (vitamin B2)
active portion is the isoalloxazine ring
carries 2 electrons and 2H+

Answer 20

FAD

Question 21

iron containing hemoproteins

iron atoms oscillates between oxidized fe3+ ferric and reduced Fe2+ ferrous states

involved as carriers of electrons from flavoproteins to cytochrome oxidase

found in the respiratory chain
Cytochromes b, c1, c, and a

Answer 21

cytochromes

Question 22

uses hydrogen peroxide or an organic peroxide as substrate

found in peroxisomes

peroxidase and catalase

Answer 22

hydroperoxidases

Question 23

hydrogen peroxide is reduced to water by substances that act as electron donors

prosthetic group is protoheme

ex: glutathione peroxidase

Answer 23

peroxidase

Question 24

contains selenium as prosthetic group catalyzes destruction of H20 and lipid hydroperoxides through conversion of reduced glutathione to oxidized glutathione

protects membrane lipids and hemoglobin
prevents hemolytic anemia

Answer 24

glutathione peroxidase

Question 25

uses hydrogen peroxide as electron donor and electron acceptor to form water

destroys hydrogen peroxide formed by oxidases

tetramer of four polypeptide chains

Answer 25

catalase

Question 26

catalyzes the direct transfer and incorporation of oxygen into a substrate molecule

1. oxygen binds to the active site of the enzyme
2. bound oxygen is reduced or transferred to a substrate
3. Two kinds: dioxygenase and monooxygenase

Answer 26

oxygenase

Question 27

incorporates both atoms of molecular oxygen into substrate

ex. homogentisate, L tryptophan and 3, hydroxyanthranilate dioxygenases

Answer 27

dioxygenase

Question 28

incorporates only 1 atom of molecular oxygen to substrate

example is cytochrome P450 important for the detoxification of many drugs and hydroxylation of steroids

Answer 28

monooxygenase

Question 29

catalyzes removal of superoxide

due to conversion of oxygen to a reactive oxygen species (ROS)

Answer 29

superoxide dismutase

Question 30

electron transport chain is made up of the following electron carriers which are

Answer 30

NAD
FMN
Co-Enzyme Q
Cytochromes B, C, A ,and A3

Question 31

collects and transports reducing equivalents and directs them to their final reaction with oxygen to form water

acts as proton pumps (COMPLEX 1, 3, 4)

coupled to oxidative phophorylation

Answer 31

electron transport chain

Question 32

electrons are transferred from NADH to coenzyme Q (ubuiquinone)

Answer 32

COMPLEX 1 - NADH-Q oxidoreductase

Question 33

FAD-linked dehydrogenase oxidizes a substrate (e.g. succinate) and passes electrons to CoQ

Answer 33

COMPLEX II - succinate q-reductase

Question 34

passes electrons from CoQ to cytochrome c

Answer 34

q-cytochrome c oxidoreductase

Question 35

transfer electrons to oxygen reducing the latter to water

Answer 35

cytochrome c oxidase

Question 36

________- links complex 1 and 2 to complex 3

Answer 36

CoQ

Question 37

____________ links complex 3 to complex 4

Answer 37

cyto c

Question 38

_____________ hydrogen are use to form 2 water and _______- are pumped in the intermembrane space

Answer 38

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