biochem exam 1 turning points Flashcards
___ is formed by an essentially irreversible process and is the “glucose donor” in the synthesis of glycogen.
A. Glucose-1-phosphate
B. Glucose-6-phosphate
C. ADP-glucose
D. UDP-glucose
D. UDP-glucose
The primer and enzyme that begins the synthesis of glycogen is…
A. Glycogen phosphatase
B. Glycogen phosphorylase
C. Glycogen synthase
D. Glycogenin
E. Glycogenkinase
D. Glycogenin
For the transformation of 1 molecule of glucose to 2 molecules of pyruvate, how many ATPs are required & produced, respectively?
A. 0, 2
B. 0, 4
C. 2, 2
D. 2, 4
E. 4, 2
D. 2, 4
At which steps of glycolysis is ATP required/consumed?
A. 1, 3
B. 1, 6
C. 3, 6
D. 6, 7, 10
E. 7, 10
A. 1, 3
At which steps of glycolysis is ATP generated/formed?
A. None
B. 6, 7
C. 6, 10
D. 7, 10
E. 6, 7, 10
D. 7, 10
at which step of glycolysis is NADPH required/consumed
none
6
7
10
none
at which step of glycolysis is NADH generated/formed
none
6
7
10
6
if aldolase is absent or not functioning in a cell, whcih intermediate iin glycolysis is most likley to accumulate when glucose is catabolized
fru 1,6 bisphos
G3P
DHAP
PEP
Pyruvate
fru 1,6 bisphos
Under anaerobic conditions in human muscle cells, pyruvate is metabolized to…
A. Acetyl-CoA
B. Ethanol
C. Lactate
D. PEP
E. TPP
C. Lactate
In gluconeogenesis, instead of reversing the PEP→pyruvate reaction, pyruvate is converted to ___, which is then converted to PEP.
A. Ethanol
B. Malate
C. Lactate
D. Oxaloacetate
D. Oxaloacetate
the metabolism of 1 pyruvate to 1 oxaloacateta etc 1 PEP required
1 ATP
1 GTP
1 ATP + 1 GTP
2 ATP + 2 GTP
2 ATP equivalents
1 ATP + 1 GTP
2 ATP equivalents
For the synthesis of 1 molecule of glucose from pyruvate, how many ATP equivalents are required and produced, respectively?
A. 2, 4
B. 4, 0
C. 4, 2
D. 6, 0
E. 6, 2
D. 6, 0
For a given reaction, ∆H = -10.6 kJ/mol and ∆S = + 7.8 kJ/mol-K. This reaction is clearly…
A. Endothermic
B. Endergonic
C. Exergonic
D. None of the above
C
given the Keq for various rxns, and the mass action ratios in given cells, which of the following rxns will be very exergonic in these cells
given these conditions, which of the following wll happen inittailly
fru 6-phos (1.5M) to glu 6-phos (0.5M)
delta G = -4.4 kJ/mol
the rxn will proceed from left to right
the rxn will proceed from right to left
the system is at equilibium so there will be not net movement
the rxn will proceed from left to right
given these conditions, which of the following wll happen inittailly
fru 6-phos (0.2M) to glu 6-phos (1.8M)
delta G = +3.7 kJ/mol
the rxn will proceed from left to right
the rxn will proceed from right to left
the system is at equilibium so there will be not net movement
the rxn will proceed from right to left
In the reaction: NAD+ <-> NADH, identify the oxidation direction, and identify the reduction direction.
A. Oxidation: L→R Reduction: R→L
B. Oxidation: R→L Reduction: L→R
B. Oxidation: R→L Reduction: L→R
which of the following pairs of rxns is a futile (substrate) cycle
1,3 bisphosphoglycerate + ADP + Pi -> 3-phosphoglycerate + ATP 3-phosphoglycerate + ATP -> 1,3 bisphosphoglycerate + ADP +Pi
3-phosphoglycerate -> 2-phosphoglycerate
2-phosphoglycerate -> 3-phosphoglycerate
glyceraldehyde 3-phosphate + NAD+ + P -> 1,3 bisphosphoglycerate + NADH
1,3 bisphosphoglycerate + NADH -> glyceraldehyde 3-phosphate + NAD+ + PI
3-phosphoglycerate -> 2-phosphoglycerate
2-phosphoglycerate -> PEP + H2O
fructose 6-phos. + ATP -> fructose 1,6-bisphos. + ADP
fructose 1,6-bisphos. + H2O -> fructose 6-phos
fructose 6-phos. + ATP -> fructose 1,6-bisphos. + ADP
fructose 1,6-bisphos. + H2O -> fructose 6-phos
it was just one of the examples he gave honestly….
Which of the following is true about the regulation of muscle hexokinase?
A. Elevated [glucose] increases activity
B. Elevated [glucose] decreases activity
C. Elevated [glc 6-phos] increases activity
D. Elevated [glc 6-phos] decreases activity
D. Elevated [glc 6-phos] decreases activity
yup, G6P will do a feedback inhibition onto hexokinase when there is too much of it so that glycolysis will stop
so hexokinase
- muscle: inhibited by G6P
- liver: activated by glucose
Which of the following is true about the regulation of liver hexokinase?
A. Elevated [glucose] increases activity
B. Elevated [glucose] decreases activity
C. Elevated [glc 6-phos] increases activity
D. Elevated [glc 6-phos] decreases activity
A. Elevated [glucose] increases activity
What effect does an elevated [AMP] have on PFK-1 activity? FBPase?
A. Increase, decrease
B. Decrease, increase
C. Increase, increase
D. Decrease, decrease
A. Increase, decrease
You’re fasting, what are your enzymes PFK-1 and FBPase-1 doing?
A. FBPase-1 more active PFK-1 less active Gluconeogenesis
B. FBPase-1 more active PFK-1 less active Glycolysis
C. FBPase-1 less active PFK-1 more active Gluconeogenesis
D. FBPase-1 less active PFK-1 more active Glycolysis
A. FBPase-1 more active PFK-1 less active Gluconeogenesis
an elevated [glucagon] leads to
an elevated [fru 2,6-BP]
a decrease in fru 2,6-BP
a decrease in fru 2,6-BP
BECAUSE fru 2,6-BP and AMP stimulate glycolysis and so more glucagon will decrease it
at a relatively high [fru 2,6-BP]
the activity of PFK-1 is relatively high
the activity of PFK-1 is relatively low
the activity of PFK-1 is relatively high
