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Block 3 Week 1 > Valencik Carb Metabolism I > Flashcards

Valencik Carb Metabolism I Flashcards

1
Q

In general, the currency to generate energy is (blank)

A

glucose

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2
Q

Determining whether a nutrient will be broken own for energy (catabolism) or used to make something (anabolism) is dependent upon what three things?

A

the delta G
Concentration of Products and Reactants
Enzymes

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3
Q

Blank are different genes with the same enzymatic activity.

A

isoform/ isozymes

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4
Q

What are the 6 things that regulate metabolism?

A 
DNA
Hormones
Vitamins
Allosteric Effectors
Epigenetics
Toxins
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5
Q

(blank) Modulates enzymes that are already made, different isozymes can have different effectors.

A

allosteric effectors

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6
Q

Which have long term effects and which have short term effects?
allosteric effectors
hormones

A

allosteric-short term

hormones-long term

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7
Q

(blank) secretes insulin and glucagon in response to changes in blood glucose concentration

A

pancreas

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8
Q

(blank) processes fats, carbs and proteins from diet, synthesizes and distributes lipids, ketone bodies, and glucose for other tissues and converts excess nitrogen to urea

A

liver

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9
Q

Where do we generate ATP?

A

mitochondria

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10
Q

Where do we synthesize/ process proteins and process membrane lipids?

A

ER/Golgi

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11
Q

Where do Biosynthetic pathways, Nonoxidative catabolism and Storage of energy reserves (fat and glycogen) occur?

A

cytoplasm

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12
Q

Where do we hydrolyze macromolecules?

A

lysosomes

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13
Q

where do oxidative reactions take place?

A

peroxisomes

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14
Q

How do you regulate enzymatic activity?

A

altering amount
altering availability
modulating activity

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15
Q

(blank) is the main carb transported in humans

A

glucose

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16
Q

During fasting, the (blank) maintains blood glucose levels

A

liver

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17
Q

blood glucose is taken up by (blank) diffusion in most tissues

A

facilitated diffusion

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18
Q

When do you have severe hypoglycemia?

A

blood glucose levels below 40mg/100 mL

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19
Q

What does the brain like more, glucose or ketones?

A

glucose!!! Will use ketones if necessary

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20
Q

What are the four major roles of carb metabolism?

A
  • generate energy from glucose
  • maintain blood glucose levels
  • channel alternative monosaccharides into energy producting pathways
  • synthesize biosynthetic monosaccharide precursors
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21
Q

WHat are the sources of blood glucose?

A

food
glycogen
gluconeogenesis
LIVER!

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22
Q

What is the main source of glucose for the blood?

A

liver

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23
Q

How does glucose travel in the blood?

A

attached to albumin

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24
Q

Fasting begins (blank) hours after eating. Then decreasing levels of insulin/glucagon stimulates (Blank) then (blank)

A

3
glycogenolysis
gluconeogenesis

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24
Q

Fasting begins (blank) hours after eating. Then decreasing levels of insulin/glucagon stimulates (Blank) then (blank)

A

3
glycogenolysis
gluconeogenesis

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25
Q

What is glycogen? what is glycogenolysis?

A

storage form of glucose

breakdown of glycogen

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25
Q

What is glycogen? what is glycogenolysis?

A

storage form of glucose

breakdown of glycogen

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26
Q

What is glucagon? When is most liver glycogen depleted?

A

a hormone formed in the pancreas that promotes the breakdown of glycogen to glucose in the liver.
After an overnight fast (10-12 hours)

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26
Q

What is glucagon? When is most liver glycogen depleted?

A

a hormone formed in the pancreas that promotes the breakdown of glycogen to glucose in the liver.
After an overnight fast (10-12 hours)

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27
Q

What process turns glucose into lactate?

A

glycolysis

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27
Q

What process turns glucose into lactate?

A

glycolysis

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28
Q

What process turns lactate into glucose?

A

gluconeogenesis

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28
Q

What process turns lactate into glucose?

A

gluconeogenesis

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29
Q

What process turns glucose into glycogen

A

glycogenesis

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29
Q

What process turns glucose into glycogen

A

glycogenesis

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30
Q

Glycolysis turns a C6 into a (blank)

A

2 molecules of C3

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30
Q

Glycolysis turns a C6 into a (blank)

A

2 molecules of C3

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31
Q

Glycolysis is the biochemical pathway through which a molecule of the six-carbon sugar glucose is converted to two molecules of the three-carbon compound pyruvate. In this process, free energy is sequestered in the form of (blank) molecules.

A

two ATP

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31
Q

Glycolysis is the biochemical pathway through which a molecule of the six-carbon sugar glucose is converted to two molecules of the three-carbon compound pyruvate. In this process, free energy is sequestered in the form of (blank) molecules.

A

two ATP

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32
Q

What are the 6 enzyme classes?

A 
transferase
isomerase
lyase
oxioreductase
hydrolase
ligases
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32
Q

What are the 6 enzyme classes?

A 
transferase
isomerase
lyase
oxioreductase
hydrolase
ligases
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33
Q

Which classes of enzymes are used in glycolysis?

A

transferase
isomerase
lyase
oxioreductase

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33
Q

Which classes of enzymes are used in glycolysis?

A

transferase
isomerase
lyase
oxioreductase

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34
Q

what cells undergo glycolysis?

A

all cells

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34
Q

What do oxioreductases do?

A

transfer electrons

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35
Q

What do lyases do?

A

break apart (or join) nonhydrolytically

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35
Q

What do lyases do?

A

break apart (or join) nonhydrolytically

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36
Q

What do isomerases do?

A

rearrange

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36
Q

What do isomerases do?

A

rearrange

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37
Q

The first reaction of glycolysis is catalyzed by the enzyme (blank), which mediates the transfer of ATP’s γ phosphoryl group to the number-6 carbon of glucose. IS this reaction reversible?

A

hexokinase (if low conc. of glucose) or Glucokinase (if high conc. of glucose)
no

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37
Q

Which enzyme is used in the presence of low amounts of glucose, hexokinase or glucokinase? WHich has a large Vmax?
WHich is inhibited by G6P?

A

hexokinase (it has a smaller Km)
glucokinase
hexokinase

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38
Q

What do ligases do?

A

couple hydrolysis of phosphanydride to bond formation

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38
Q

What do ligases do?

A

couple hydrolysis of phosphanydride to bond formation

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39
Q

Where do you find the glut 1 transporter and what is its function?

A

most tissues

basal glucose uptake

39
Q

Where do you find the glut 1 transporter and what is its function?

A

most tissues

basal glucose uptake

40
Q

Where do you find the glut 2 transport and what is its function?

A

liver, intestine, pancreatic B cells

high-capacity glucose uptake

40
Q

Where do you find the glut 2 transport and what is its function?

A

liver, intestine, pancreatic B cells

high-capacity glucose uptake

41
Q

Where do you find glut 3 tranporter and what is its function?

A

brain

neuronal glucose uptake

41
Q

Where do you find glut 3 tranporter and what is its function?

A

brain

neuronal glucose uptake

42
Q

Where do you find glut 4 transport and what is its function?

A

muscle, adipose tissue, heart

insulin-dependent glucose uptake

42
Q

Where do you find glut 4 transport and what is its function?

A

muscle, adipose tissue, heart

insulin-dependent glucose uptake

43
Q

Where do you find glut 5 transporter and what is its function?

A

intestine

fructose transport

43
Q

Where do you find glut 5 transporter and what is its function?

A

intestine

fructose transport

44
Q

what cells undergo glycolysis?

A

all cells

44
Q

what cells undergo glycolysis?

A

all cells

45
Q

What are the three major stages of glycolysis?

A

priming
splitting
oxioreduction-phosphorylation stage

45
Q

What are the three major stages of glycolysis?

A

priming
splitting
oxioreduction-phosphorylation stage

46
Q

What stage is this:

D-Glucose + 2 ATP4-→D-fructose 1,6-bisphosphate4- + 2 ADP 3- + 2 H+

A

Priming stage

46
Q

What stage is this:

D-Glucose + 2 ATP4-→D-fructose 1,6-bisphosphate4- + 2 ADP 3- + 2 H+

A

Priming stage

47
Q

What stage is this:

2 D-Glyceraldehyde 3-phosphate2- + 4 ADP3- + 2 Pi- + 2 H+→2 L-lactate- + 4ATP4- + 2 H2O

A

Oxioreduction-phosphorylation stage

47
Q

What stage is this:

D-Fructose 1,6-bisphosphate4-→2 D-glyceraldehyde 3-phosphate2-

A

splitting stage

47
Q

What stage is this:

2 D-Glyceraldehyde 3-phosphate2- + 4 ADP3- + 2 Pi- + 2 H+→2 L-lactate- + 4ATP4- + 2 H2O

A

Oxioreduction-phosphorylation stage

48
Q

Glycolysis only proceeds when delta G of all individual reactions are (Blank)

A

negative

49
Q

The first reaction of glycolysis is catalyzed by the enzyme (blank), which mediates the transfer of ATP’s γ phosphoryl group to the number-6 carbon of glucose. IS this reaction reversible?

A

hexokinase

no

50
Q

Which enzyme is used in the presence of low amounts of glucose, hexokinase or glucokinase?

A

hexokinase (it has a smaller Km)

51
Q

What is the second reaction of glycolysis?

A

the isomerization of glucose 6-phosphate to fructose-6 phosphate.

52
Q

What enzyme converts G6P to F6P?

A

phosphohexose isomerase

53
Q

What catalyzes the commited step (rate-limiting step) of glycolysis?
What does a defect in this cause?

A 
phosphofructokinase 1 (PFK1)
Tarui's Disease
54
Q

What does PFK1 do?

A

it transfers ATP to F6P creating F1,6 BP

55
Q

(blank) cleaves the 6-carbon monosaccharide fructose-1,6-bisphosphate into two 3-carbon molecules, glyceraldehyde-3-phosphate and dihydroxyacetone phosphate.

A

aldolase

56
Q

When aldolase is used to turn F1,6 BP into a huge amount of DHAP and a small amount of G3P, how does the reaction move forward to continue glycolysis?

A

G3P is continuously consumed causing the reaction to shift towards creating more G3P and making the reaction favorable (i.e delta G is negative)

57
Q

How do you convert the DHAP to G3P?

A

With a triose and fast consumption of G3P

58
Q

The next step in glycolysis is the conversion of G3P to 1,3 bisphosphateglycerate, however this would seem energetically unfavorable, how does this reaction continue forward?

A

1,3BPG is rapidly consumed and the substrate NAD+ (when in high concentration) can drive the reaction forward

59
Q

What does G3P dehydrogenase do?

A

catalyzes the addition of a phosphate group to G3P to make 1,3BPG

60
Q

What is the first reaction of glycolysis in which free energy is recovered?

A

the reaction of 1,3 BPG and phosphoglycerate kinase turning into 3PG : ))))

61
Q

Why can we get ATP from 1,3 BPG?

A

because of the high negative free energy of the hydrolysis of the phosphate group

62
Q

What does phosphoglycerate mutase do?

A

turns 3PG to 2PG

63
Q

What does ENolase do?

A

converts 2PG to PEP

64
Q

What is the second reaction in which free energy is recovered in the form of ATP?
Is this reaction reversible?
How many net ATP do we have?

A

PEP to pyruvate via Pyruvate Kinase
NO!!!
two : )))

65
Q

How do we get ATP from PEP?

A

from the hydrolysis of PEP and the tautormerism of pyruvate

66
Q

Which form of pyruvate is more stable, the enol form or the keto form?

A

the keto form

67
Q

What is the investment and what is the pay off of glycolysis?

A

2 ATPS

2 ATPS and 2 NADHs

68
Q

What is the first reaction of glycolysis?

A

the conversion of glucose to g6p by glucokinase. This only happens under very high amounts of glucose due to the high Km of glucokinase.

69
Q

where do you find glucokinase?

A

liver and pancreatic B cells

70
Q

In anaerobic conditions, or in the absence of mitochondria (RBC’s) coverts glucose to (blank) with a net of (blank) ATPs and regenerates (blank)

A

lactic acid
2 ATPs
NAD for G3P

71
Q

What happens to the lactate at the end of anerobic respiration? HOwever, lactate can reenter glycolysis at pyruvate but not in (blank).

A

it is a dead end and makes cells acidic

RBCs

72
Q

(blank) generally moves in the blood stream back to the liver to be shuttled back into glycolysis.

A

lactate

73
Q

If aerobic respiration where do we shuttle pyruvate?

A

into the mitochondria

74
Q

What leads to lactic acidosis?

A

anything that impairs oxygen or inhibits TCA cycle

75
Q

What will this lead to and why:

physical excercise

A

lactic acidosis

anaerobic glycolysis in muscle

76
Q

What will these lead to and why?

server lung disease, high altitude, drowning

A

lactic acidosis

impaired respiration

77
Q

What will these lead to and why?

Severe anemia, Carbon monoxide poisoning, Sickling crisis

A

lactic acidoss

impaired oxygen delivery

78
Q

What will these lead to and why?

cyanide poisoning

A

lactic acidosis

inhibition of oxidative phosphorylation

79
Q

What will these lead to and why?

Alcohol intoxication, Von Gierke’s disease

A

lactic acidosis
elevated NADH/NAD+ ratio
impaired gluconeogenesis

80
Q

What will these lead to and why?

pyruvate dehydrogenase deficiency

A

lactic acidosis

impaired pyruvate oxidation

81
Q

What will these lead to and why?

Leukemia, Metastatic carcinoma

A

lactic acidosis

Anaerobic glycolysis by neoplastic cells

82
Q

What traps glucose inside of the cell

A

glucokinase

83
Q

What is the commited step, and catalyzes the first unique irreversible reaction in glycolysis?

A

PFK1

84
Q

What is the regulation of glucokinase?
What inhibits glucokinase?
What activates it?

A

regulated by glucokinase regulatory protein that shuttles GK in/out of nucleus depending on glucose levels. Shuttled out if glucose is high and visa versa.

2) low levels of glucose and high levels of F6P
3) high levels of glucose and high levels of fructose

85
Q

What is an allosteric activator of PFK1?
What is an allosteric inhibitor of it?
Why?

A

AMP
ATP
If you have a lot of ATP you want to shut off glycolysis.

86
Q

What is F2, 6 bis-P?

A

made in the liver from F6P in the presence of insulin and is an allosteric effector (activates) of PFK1

87
Q

WHen does F6P turn into F2, 6BP and when does F2,6BP turn into F6P?

A

in presence of insulin

in presence of glucagon

88
Q

Increase in (Blank) signals fasting, and you need blood glucose , therefore you will slow glycolysis in the liver.

A

glucagon

89
Q

Increase in (blank) means you are well fed, with plenty of glucose, therefore glycolysis is allowed in the liver.

A

insulin

93
Q

(blank) signals an abundance of energy being generated by the TCA cycle.

A

citrate

94
Q

What are the 5 components that inhibit PFK1?

A

ATP, Citrate, low pH, low F2,6 BP, glucagon

95
Q

What are the three components that inhibit pyruvate kinase?

A

ATP, Alanine, phosphate

96
Q

What are the three activators of PFK1?

A

F2,6BP, AMP, insulin

97
Q

Deficiency of (blank) causes problems in RBC’s which results in hemolytic anemia

A

pyruvate kinase

98
Q

(blank) forms an unstable mixed anhydride with G3P. After spontaneous hydrolysis, 3-phosphoglycerate (3PG) feeds back into glycolysis, but there is no net ATP from glycolysis.

A

arsenate

99
Q

(blank) poisons PDH by binding to the sulfhydryl groups in dihydrolipoic acid. Much more toxic.

A

arsenite

100
Q

(blank) protects teeth by inhibiting enolase preventing the formation of both pyruvic and lactic acid helping to prevent tooth decay. It also incorporates into the dentin to strengthen the surface of the teeth.
.

A

fluoride

101
Q

The addition of (blank) to blood samples stops glycolysis allowing blood glucose levels to be measured.

A

fluoride

102
Q

Glycolysis is different in RBCs. What is the major phosphorylated intermediate in the RBC?
What does glycolysis in the RBC bypass and what does this result in?

A

2,3 BPG

Bypasses phosphoglycerate kinase reaction, therefore net ATP per mole glucose is decreased to 0.

103
Q

RBC’s are not biosynthetic cells (enucleate). They only need energy to (blank) and maintain a (blank).

A

survive

membrane potential

104
Q

What enzyme turns 1,3 BPG into 2,3 BPG in the RBC?

A

2,3 bisphospholycerate mutase

105
Q

What converts 2,3 BPG into 3 PG or 2PG in the RBC?

A

2,3 bisphosphoglycerate phosophotase

106
Q

RBC’s use (Blank) glucose/day

A

15-20g

115
Q

What allosterically stimulates pyruvate kinase?

A

F1,6 bisphosphate in the liver

117
Q

WHat is the allosteric effector (activator) of pyruvate kinase?
HOw does it work?

A

fructose 1,6 bis-phosphate

It feedforward stimulates

130
Q

What are the effectors of glycolysis in the RBC:
for Hexokinase?
For PFK1?
For Pyruvate Kinase?

A

-G6P, -ATP
+AMP, -ATP +F2,6 BP
+F1,6BP, -ATP

131
Q

What are the effectors of glycolysis in the RBC:
for Hexokinase?
For PFK1?
For Pyruvate Kinase?

A

-G6P, +ATP
-ATP, +AMP, +F2,6 BP
+F1,6BP, -ATP

132
Q

Once the committed step of glycolysis has passed, it makes sense to stimulate the irreversible enzyme downstream which is pyruvate kinase. What does this?

A

F1,6 BP

Block 3 Week 1 (18 decks)

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