Brainscape's Knowledge GenomeTM

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


See full index

Biochemistry II > Exam 2: Sample Questions > Flashcards

Exam 2: Sample Questions Flashcards

1
Q

provide 6 functions of the PPP

A
  1. NADH
  2. prevents oxidative stress
  3. major route of glucose metabolism
  4. xenobiotic metabolism
  5. scrambles glucose carbons
  6. nucleotide synthesis
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

what are the 2 modes of the PPP?

A
  1. cellulose division
  2. fatty acid synthesis
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

the cellulose division mode of the PPP requires?

A

R-5-P

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

what are the metabolic event that occur in the cellulose division mode of the PPP.

A

glycolysis intermediate is used to make more R-5-P

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

the fatty acid synthesis mode of the PPP requires?

A

more NADPH

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

the fatty acid synthesis mode of the PPP includes what metabolic event?

A

parts of gluconeogenesis is used to make more G-6-P

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

what is the regulatory step of the PPP?

A

G-6-P

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

what enzyme regulates G-6-P?

A

dehydrogenase

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

dehydrogenase is inactivated by….

A
  • increase in NADPH
  • decrease in NADP+/NADPH ratio
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

what hormone activates dehydrogenase?

A

cortisol

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

what rxns are unique to gluconeogenesis?

A
  • pyruvate carboxylase
  • moving OAA to the cytosol
  • PEPCK
  • F16BiPhosphate
  • G-6-phosphatase
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

what role does translocase play in fatty acid metabolism?

A

during exchange step of setting up fatty acids it exchanges carnitine far acyl carnitine

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

How many FADH2 and NADH molecules would be formed from an 8 carbon fatty acid through fatty acid oxidation?

A

3 FADH2
3 NADH

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

describe how unsaturated fatty acid oxidation differs from saturated fatty acid

A

saturated fatty acid oxidation forms FADH2 and NADH and consecutively undergoes β-oxidation until making acetyl CoA

unsaturated fatty acid oxidation cis-trans isomerase flips fatty acid if necessary then it undergoes β-oxidation until making acetyl CoA

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

both saturated and unsaturated fatty acids go through hydration by enoyl-CoA hydratase to form…

A

L-β-hydroxyacyl-CoA

D-β-hydroxyacyl-CoA

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

what is the prosthetic group of pyruvate carboxylase?

A

biotin

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

what is the significance of biotin in fatty acid oxidation?

A

it increased utilization of glucose for fat synthesis

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

provide 4 reasons why the production of ketone bodies is important?

A
  1. less toxic
  2. more soluble
  3. bypass regulatory points
  4. spares glucose
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

provide 3 conditions under which amino acids would be oxidized

A
  1. diet excess
  2. starvation
  3. cellular situations (diabetes)
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

what role does pyruvate carboxylase play in gluconeogenesis?

A

adds bicarbonate to pyruvate to form oxaloacetate

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

provide 3 ways that organisms can deal w/ ammonia & excess nitrogen

A

ammonia
- ammoniotelic
- uricotelic
- ureotelic

nitrogen
- urea cycle

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

what molecule links the TCA cycle to the urea cycle?

A

fumerate

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
23
Q

Describe how glutamate (GLU) and glutamine (GLN) metabolism are involved in pH homeostasis.

A
  • At normal pH: Gln = Glu production
  • At acidic pH: there’s a decrease in the production of Gln -> Glu + NH4+
  • At basic pH: there is a increase in the production of Gln -> Glu+ NH4+
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
24
Q

What is the preferred methyl carrier metabolically and why?

A
  • SAM (S-adenosyl methionine)

b/c it contains a sulfonium ion

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
25
Q

provide 3 reasons why sugar nucleotides are used in metabolism.

A
  • irreversible
  • increase enzyme interactions
  • good leaving group: nucleotide
  • resource allocation
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
26
Q

what is the rate limiting enzyme in glycogenolysis?

A

glycogen phosphorylase

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
27
Q

glycogen phosphorylase requires what coenzyme to be active?

A

pyridoxal phosphate

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
28
Q

what is the summarized mechanism for glycogen phosphorylase?

A

removes end glucose on glycogen to generate G-1-P

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
29
Q

what are the 4 steps in the mechanism of glycogen phosphorylase?

A
  1. donates proton to 4C on glycogen chain
  2. donates protein to inorganic phosphate
  3. forms carbonium ion intermediate
  4. Pi attacks intermediate forming G-1-P

proton is given back to pyridoxal phosphate

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
30
Q

what is the 1st reaction for many amino acids?

A

transamination reaction

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
31
Q

what is the actual reaction for the transamination reaction?

A

converting α-keto acid to glutamate

by transfer of amino group to carbon atom of α-ketoglutarate

32
Q

what coenyme do transaminases require?

A

pyridoxal phosphate (PLP)

33
Q

what molecule plays an important role in getting fatty acids into the MTCH?

A

carnitine acyl transferase I (CATI)

34
Q

what effect does fructose-2,6-biphosphate have on gluconeogenesis and glycolysis?

A
  • gluconeogenesis: inhibits
  • glycolysis: stimulates
35
Q

what is the significance of CoA to fatty acid oxidation?

A

thiolytic cleavage uses CoA

36
Q

explain the role of glycogenin in glycogen synthesis

A
  • glycogenin attaches glucose molecule to tyrosine residue
  • complex is formed between glycogenin and glycogen synthase (allows attachment of glucose molecules)
  • finally glycogen synthesis forms a large chain
37
Q

what ultimately decides if a molecule is glucogenic or ketogenic?

A

determined based on whether the carbon skeleton can be made into glucose or acetyl CoA

38
Q

describe the hormonal regulation of acetyl CoA carboxylase

A
  • inactivated through dephosphorylation by insulin
  • activated through phosphorylation by glucagon
39
Q

list the 3 major activities of the fatty acid synthesis complex

A
  1. entry/condensation
  2. reduction of = bond (master step)
  3. release of molecule
40
Q

describe the role of vitamin B12 in amino acid metabolism

A

rearranges the carbon skeleton

41
Q

provide 3 ketone bodies that can be formed

A
  1. acetoacetate
  2. acetone
  3. hydroxybutyrate
42
Q

how does odd-chain fatty acid oxidation differ from even chain fatty acid oxidation?

A
  • odd-chain produces benzoate
  • even-chain produces phenylacetate
43
Q

what is the role of hormone sensitive lipase in fatty acid metabolism?

A
  • to break down triglycerides into:

glycerol & 3 fatty acids

44
Q

describe the Cori Cycle

A

process of transporting lactate from cell undergoing anaerobic respiration to liver where it is used to provide glucose back to cells

transporting liver energy

45
Q

what are the organs involved in the Cori Cycle?

A

liver & muscle

46
Q

what are the major molecules of the Cori Cycle?

A
  • lactate
  • glycogen
  • glucose
47
Q

list 3 arachidonic acid products

A
  1. prostaglandins
  2. thromboxane
  3. prostacyclin
  4. leukotrienes
48
Q

what are the effects of prostaglandins?

A
  • transit of RBCs
  • decrease gastric acid production
49
Q

what is the effect of thromboxane

A
  • blood clotting
50
Q

what is the effect of prostacyclins

A
  • basodialators
  • decrease platelet aggregation
51
Q

what is the effect of leukotrienes?

A
  • allergic reactions
  • promote inflammation
52
Q

what is the source of all the carbons found in cholesterol?

A

acetyl CoAs

53
Q

what is the role of HDL and LDL in regards to cholesterol transport?

A

HDL: transports cholesterol to the liver
LDL: transports cholesterol to tissues

54
Q

what are the 5 stages of cholesterol synthesis?

A
  1. mevalonate production
  2. isoprenoids
  3. squalene
  4. cyclize squalene to lanosterol
  5. formation of cholesterol
55
Q

what is a similarity of chylomicrons and VLDL?

A
  • both aid in transport of triglycerides through the blood
56
Q

what is a difference between chylomicrons AND VLDL?

A

chylomicrons: dietary lipids seen in the GI tract
VLDL: endogenous — seen in the liver

57
Q

what is the 3 carbon carrier used in fatty acid synthesis?

A

acyl carrier protein (ACP)

58
Q

what role does thioesterase play in determining the fatty acid that a particular cell produces?

A

dictates if a molecule is palmitate or something else during the cleavage stage of fatty acid synthesis

59
Q

what are the 2 types of attachment for glucose molecules in glycogen?

A
  • α 1,4 linkage —–main chain
  • α 1,6 linkage——-branching points of main chain
60
Q

what are the 2 glycogen storage diseases?

A
  1. Pompe’s
  2. Anderson’s
61
Q

the disease Pompe’s occurs in the ______________ and leads to _________________

A

lysosomes

respiratory failure

62
Q

the disease Anderson’s occurs in the ____________ and leads to ___________

A

liver

liver failure

63
Q

name two amino acids that can undergo direct deamination. Why?

A
  1. serine
  2. threonine
  • they contain an OH group
64
Q

what are the 2 sources of nitrogen in the urea compound?

A
  1. glutamate/glutamine
  2. aspartate
65
Q

what effect does dietary nitrogen have on enzymes in the urea cycle?

A
  • it down regulates the enzymes

- ex: too much protein in civil war & concentration camps

66
Q

diagram the glucose/alanine cycle

A
  • glucose converted to alanine in muscle
  • alanine spills into the blood
  • alanine converts to glucose in liver
  • glucose is transported into muscle
67
Q

what role does pyridoxal phosphate play in amino acid synthesis?

A
  • cofactor for aminotransferases
  • forms Schiff-base linkage w/ specific lysine group of aminotransferase enzyme
68
Q

overall reaction for synthesis of palmitate

A

8AcCoA + 7ATP + 14NADPH ————–> palmitate + 14NADP+ + 6H2O + 7ADP + 7Pi + 8CoA

69
Q

what are the 2 enzymes that metabolize/modify arachidonic acid?

A
  • cyclooxygenase
  • lipoxygenase
70
Q

what types of molecules are formed by cyclooxygenase?

A
  • prostaglandins
  • prostacyclin
  • thromboxane
71
Q

what types of molecules are formed by lipoxygenase?

A
  • leukotrienes
72
Q

what types of molecules are formed by lipoxygenase?

A
  • leukotrienes
73
Q

fatty acids can be modified into their ____________ and _________________ forms

A

ester

thioester

74
Q

what are the 3 sources of NADPH for fatty acid synthesis?

A
  1. PPP
  2. hexose monophosphate
  3. malic enzyme
75
Q

what are the 2 modifications that can be made to fatty acids? what are the enzymes responsible for this?

A
  • elongate ———–elongase
  • desaturation —————desaturase
76
Q

what is the overall reaction for the PPP?

A

G-6-P + 2NADP+ + H2O ——————> R-5-P + 2NADPH + 2H+ + CO2

Biochemistry II (6 decks)

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