Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

Biochemistry II > Exam 1 > Flashcards

Exam 1 Flashcards

1
Q

A rxn. in a catabolic pathway is found to have a large -Gibbs free enerfy. How likely is it that this rxn is a regulatory step in the pathway?

A

Very likely. Large -Gibbs Free energy means rxn. is further from equilibrium making it more irreversible (better regulatory step)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

what are some likely general products of a catabolic pathway?

A
  • ATP
  • GTP
  • NADH
  • FADH2
  • Acetyl CoA
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

list the control steps for the TCA cycle

A
  1. citrate synthase
  2. isocitrate dehydrogenase
  3. a-ketoglutarate dehydrogenase
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

provide the allosteric activators and inactivators of pyruvate dehydrogenase enzyme.

A

inactivators: ATP, acetyl CoA, NADH
activators: AMP, CoA, NAD+

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

how does citrate help tie glycolysis activity to the TCA cycle?

A
  • in TCA cycle Acetyl-CoA reacts w/ oxaloacetate to make citrate
  • citrate buildup in MTCH causes spilling into the cytosol
  • citrate in cytosol inhibits PFK-1
  • inhibition indicates no need for the breakdown of glucose b/c MTCH is high energy
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

provide 5 ways to regulate a metabolic pathway

A
  1. amount of enzymes
  2. catalytic activity
  3. compartmentalization
  4. energy charge
  5. isoenzymes
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

what are all the fates of G-6-P in non-liver cells?

A
  • glucosamine
  • PPP
  • glycolysis
  • glycogen
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

list similarities between pyruvate dehydrogenase and a-ketoglutarate dehydrogenase

A
  • control scheme
  • thioester produces
  • products
  • 3 enzymes
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

list the 3 control steps in glycolysis. which one is considered the pacemaker?

A
  1. HK/GK
  2. PFK-1
  3. pyruvate kinase

PFK-1 is the PACEMAKER

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

provide 2 differences between anabolic and catabolic processes

A

catabolic
- enzymes are activated by phosphorylation
- makes ATP

anabolic
- enzymes are inactivated by phosphorylation
- uses ATP

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

14). List the two shuttles responsible for transferring reducing equivalents from glycolysis into the mitochondria. What is the major difference between these two?

A
  1. matate-asparatate shuttle
  2. glycerol-3-phosphate shuttle

difference: malate is slower but more efficient & produces more ATP b/c electrons are transferred to NAD+ instead of FAD

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

15). Write the overall reaction for glycolysis and explain where the other two protons come from.

A
  • phosphorylation of glucose to G-6-P
  • phosphorylation of F-6-P to F-1,6-BiP
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

16). Fully describe the mechanism for phosphoglycerate mutase

A
  1. phosphoenzyme with His residue at the active site binds w/ 3-phosphoglycerate
  2. phosphoenzyme transfers phosphate group from HIS residue to 2 position of 3-phosphoglycerate making 2-3 biphosphoglycerate
  3. phosphate at 3 position of 2-3biphosphoglycerate is + to HIS residue. Making 2-phosphoglycerate. regenerating phosphoenzyme
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

Which of the following is not an intermediate of the citric acid cycle?
A) oxaloacetate
B) citrate
C) α-ketoglutarate
D) succinyl-CoA
E) pyruvate

A

pyruvate

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

18). Use an example from one glycolysis or the TCA cycle to briefly explain the concept of isozymes.

A

different structure but catalyze the same rxn. HK and GK both catalyze the phosphorylation of glucose

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

19). Use an example from glycolysis and the TCA cycle that we have discussed so far to briefly describe the term flux.

A
  • flux is net metabolite movement
  • crucial in pathways that change with varying conditions
  • Glycolysis: phosphofructokinase serves as control step
  • TCA cycle: isocitrate dehydrogenase serving as control step
17
Q

20). Describe the term substrate level phosphorylation and provide 3 examples discussed in class.

A
  • substrate-level phosphorylation is the transfer of phosphate to ADP from another phosphorylated compound
  1. succinyl-CoA synthetase
  2. phosphoglycerate kinase
  3. pyruvate kinase
18
Q

21). Explain how kinases use induced fit as well as magnesium to catalyze their reactions.

A
  • induced-fit: prevent unwanted hydrolysis of ATP by H2O (closes the H2O active site)
  • magnesium: acts as cofactor allowing facilitated rxn between ATP and glucose
19
Q

22). Provide three functions for GTP in cells.

A

important to the formation of

  1. proteins
  2. cAMP
  3. ATP
20
Q

Explain why succinate dehydrogenase is called the mixer reaction and the role it plays in linking the TCA cycle to the ETS.

A
  • mixer rxn. b/c the label is lost w/ the formation of fumerate
  • links: oxidizes succinate to form fumerate & causes the regeneration of FADH2

Biochemistry II (6 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions