Metabolism Flashcards Preview

NBDE PART 1 BIOCHEM/PHYSIOLOGY > Metabolism > Flashcards

Flashcards in Metabolism Deck (62):
1

which complex contains cytochromes b and c1 and an Fe-S center:
complex I, II, III, IV?

complex III

2

electrons from NADH are transferred to the __

FMN prosthetic group of NADH-Q: COMPLEX I

3

succinate dehydrogenase (the enzyme found in TCA) is in complex

COMPLEXII

4

the mobile carriers of electrons are

cytochrome c and Q

5

cytochrome c oxidase is

Complex IV

6

cytochromes a and a3 are in

complex IV

7

how many molecules of ATP per NADH oxidized

2.5

8

how many molecules of ATP per FADH2 oxidized

1.5

9

glucokinase is in the

liver!

10

difference bw glucokinase and hexokinase:
1. which one has higher affinity (lower Km)
2. which one can only catalyze glucose

1. glucokinase has lower affinity
2. glucokinase only glucose
While other hexokinases are capable of phosphorylating several hexoses, glucokinase acts with a 50-fold lower substrate affinity and its only hexose substrate is glucose

11

cycle where glucose and lactate shuttle bw muscle and liver

cori cycle aka lactic acid cycle

12

the cori cycle functions more efficiently when muscle activity has

ceased bc oxygen debt can be made up so that the citric acid cycle and electron transport chain also work

13

2 places in body lactic acid produced

RBC and active muscle

14

pyruvate is converted to acetyl coA by

pyruvate dehydrogenase = enzyme
NAD+, CoA, and pyruvate ==> CO2 + Acetyl-CoA + NADH

15

pyruvate is converted to lactic acid by

lactate dehydrogenase = enzyme
pyruvate + NADH ==> lactate + NAD+

16

the glycolytic pathway is:
a. aerobic
b. anaerobic
c. facultative

it is called ANAEROBIC bc it does not need oxygen

17

what happens to the carbons and oxygens of glucose?

released as waste! one carbon lost from pyruvate ==> Acetyl CoA ==> TCA lose the other two

18

is TCA
a. aerobic
b. anaerobic
c. facultative

a. aerobic

19

glycolysis is _ and TCA is __
a. aerobic
b. anaerobic
c. facultative

glycolysis anaerobic
TCA aerobic

20

the most common pathway of glycolysis is

Embden-Meyerhof pathway

21

Embden-Meyerhof pathway is a specific glycolytic pathway by which

glucose converted to pyruvate

22

oral bacteria use which pathway

Embden-Meyerhof pathway = anaerobic and facultative bacteria

23

Embden-Meyerhof pathway will take pyruvate and

make lactic acid and 2 ATP per molecule of glucose metabolized

24

the Entner Doudoroff pathway is an alternative to glycolysis used by many _ bacteria

obligate aerobic bacteria.

25

1. the Entner Doudoroff pathway results in the net production of _ ATP
2. Embden-Meyerhof pathway results in the net production of _ ATP

1. one ATP by substrate level phosphorylation
2. two ATP

26

the Entner Doudoroff pathway ends with production of

pyruvate and glyceraldehyde 3 phosphate (which is converted by enzymes outside the pathway to pyruvate).

27

the Entner Doudoroff pathway bacteria lack which enzymes of the Embden-Meyerhof pathway?

either 6-PFK or aldolase

28

the _ pathway oxidized hexose and glucose 6 phosphate makes 5C sugars. it generates reducing equivalents ___

pentose phosphate pathway
NADPH

29

NADPH is used in ___ reactions

reductive biosynthesis pathways (FA/steroid synthesis)

remember oxidative pathways are catabolic ie. just remember glucose

30

does the pentose phosphate pathway
require ATP for phosphorylation

no. no ATP is consumed or produced directly in the cylce

31

pentose phosphate pathway
consists of 2 __ oxidative reactions followed by a series of reversible sugar phosphate interconversions

irreversible

32

pentose phosphate pathway
occurs where in the cell

cytosol

33

pentose phosphate pathway
produces ribose 5 phosphate which is required for

synthesis of nucleotides

34

the __branch of the pentose phosphate pathway
synthesizes NADPH

oxidative

35

the rate limiting step in pentose phosphate pathway enzyme

G6P DH

36

the _ branch links ribulose 5 P (the product of the oxidative rxns) to glycolytic and gluconeogenic pathways

non oxidative

37

most important enzymes in the reversible reactions of the non oxidative PPP are

tranketolase and transaldolase

38

PPP activity is _ in muscle and brain

minimal.

39

PPP important in what organs

liver and mammary glands adrenal cortex

40

PPP important in cells exposed to high

oxygen partial pressure

41

___ pathway important in cornea of eye

cornea of eye = 60% of total glucose consumption via PPP

42

the _ portion of PPP is not reversible

oxidative
makes NADPH

43

the __ portion of PPP generates the sugars so they can re enter glycolysis

nonoxidative

44

__ is the first phase of respiratory metabolism of glucose and _ is the 2nd, and _ is the 3rd

glycolysis
tca
e transport chain

45

photophosphorylatin occurs as a result of

photosynthesis (which also involves the electron transport chain)

46

oxygen uptake which is dependent on the presence of ADP phosphate and an electron donor is called

coupled respiration

47

THEORETICALLY most human cells: one glucose molecule produces enough chemical energy to synthesize:
32-34 ATP
36-38 ATP

36-38

48

which cells may synthesize 38 electrons?

heart and liver cells that shuttle electrons more efficiently

49

a net profit of _ ATP is produced by substrate level phosphorylation during glycolysis and TCA

4 ATP (2 glycolysis + 2 TCA)

50

___ ATP form oxidative phosphorylation

32-34ATP during e- transport

51

glucose is completely oxidized to

CO2 and water (not oxygen!!!! oxygen is the final electron acceptor and turns into water)

52

THEORETICALLY glucose oxidation to CO2 and H20 makes _ ATP
in reality it is

theoretically: 36-38 (counting NADH as 3ATP and FADH2 as 2ATP - theoretical)
in realtiy: 30-32ATP (really NADH is 2.5 and FADH2 is 1.5)

53

T/F gluconeogenesis is the reverse of glycolysis

false

54

gluconeogenesis produces glucose from (3)

amino acids
lactate
glycerol

55

gluconeogenesis uses the __ reactions of glycolysis and bypasses the __ ones

uses the reversible steps and bypasses the irreversible steps

56

__ is the only source of glucose during long term fasting

gluconeogenesis

57

only the _ can do GNG

liver and kidneys

58

how many steps in GNG

11

59

GNG begins in the _ with the formation of _. enzyme? energy?

mitochondria forms OAA
pyruvate + CO2 +ATP ==> OAA
pyruvate carboxylase

60

OAA is then reduced to __ using __ in order to be transported out of mitochondria in GNG

malate
NADH

61

Name the enzymes in GNG that are unique

pyruvate carboxylase (pyruvate ->OAA)
PEP carboxykinase (OAA --> PEP)
F1,6 Bisphosphatase (F1,6BP -->F1,6)
glucose 6 phosphatase: in ER, forms glucose

62

1. lactate dehydrogenase
2. pyruvate dehydrogenase

1. make lactic acid
2. make acetylCoA