Brainscape's Knowledge GenomeTM


Top Flashcards (Certified)
All Flashcards

Biochem Final > Lecture 13 - Gluconeogenesis > Flashcards

Lecture 13 - Gluconeogenesis Flashcards

(68 cards)

Start Studying
1
Q

Is gluconeogenesis the exact reverse of glycolysis?

A

NO - differs at 3 steps

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

Gluconeogenesis converts ___ back to ___

A

converts pyruvate back to glucose

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

When will gluconeogenesis occur?

A

in times of fasting

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

Gluconeogenesis is a pathway for forming glucose using ______ precursors

A

non-carbohydrate precursors

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

Name some non-carbohydrate precursors that can be used in gluconeogenesis

A

lactate, glycerol, and numerous amino acids

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

Gluconeogenesis occurs almost exclusively in…

A

the liver

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

Why is gluconeogenesis so important?

A

It’s important in maintaining blood glucose levels

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

What is the rate-limiting step in gluconeogenesis?

A

pyruvate—>—>PEP

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

The conversion of pyruvate to phosphoenolpyruvate requires ___ steps. Name them

A

2 steps:

pyruvate—>oxaloacetate

oxaloacetate–>phosphoenolpyruvate

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

pyruvate—> oxaloacetate
is catalyzed by the enzyme….

A

Pyruvate Carboxylase

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

oxaloacetate->PEP
is catalyzed by the enzyme….

A

Phosphoenolpyruvate Carboxykinase

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

Where is the enzyme pyruvate carboxylase located?

A

in the matrix of the mitochondria

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

Since the enzyme pyruvate carboxylase is located in the mitochondria, what must happen to pyruvate?

A

cytosolic pyruvate must be transported into the mitochondria through the pyruvate transport system

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

What is the rate limiting ENZYME in gluconeogenesis?

A

phosphoenolpyruvate
carboxykinase

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

the production of oxaloacetate is catalyzed in the _____

A

mitochondria

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

the conversion of oxaloacetate –> PEP occurs in…

A

the cytosol

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

Since the conversion of oxaloacetate–>PEP occurs in the mitochondria…

A

oxaloacetate must be indirectly transported to the inner mitochondrial membrane

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

What are the 2 conversions by which oxaloacetate enters the inner mitochondrial membrane?

A
  1. Reduction to malate
  2. Transamination to aspartate
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

The 2 conversions involved in transporting oxaloacetate into the inner mitochondrial membrane are…

A

near equilibrium

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

What enzyme catalyzes the reduction to malate?

A

malate dehydrogenase

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

What enzyme catalyzes the transamination to aspartate?

A

aspartate aminotransferase

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

What is the gluconeogenesis reaction that bypasses the PFK step in glycolysis?

A

Fructose-1,6-biphosphate
–>
Fructose-6-Phosphate

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

What enzyme catalyzes the conversion of Fructose-1,6-biphosphate to fructose-6-phosphate?

A

fructose-1,6-biphosphatase

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
24
Q

What is the mechanism of the reaction catalyzed by fructose-1,6-biphosphatase?

A

the hydrolysis of the phosphate bond

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
25
Fructose-1,6-biphosphatase is activated by what molecule?
citrate
26
Fructose-1,6-biphosphatase is allosterically INHIBITED by what molecule?
fructose-2,6-biphosphate
27
What is the last step of gluconeogenesis and what enzyme catalyzes it?
Glucose-6-phosphate-> Glucose catalyzed by glucose-6-phosphatase
28
The regulation of Glucose-6-Phosphate -> Glucose is regulated through ____ means
genetic
29
glucose-6-phosphate--> glucose is INCREASED during.....
starvation directed by glucagon
30
glucose-6-phosphate-> glucose is SUPPRESED in ___ state directed by ____
fed state directed by insulin
31
When does the pancreas release insulin?
when blood sugar (glucose)enters our blood stream
32
What does insulin do?
helps glucose enter the body's cells so it can be used for energy ALSO signals the liver to store glucose as glycogen for later use
33
Insulin ___ blood glucose levels
lowers
34
During a meal, glucose moves from the ____ to the ___
from the digestive tract to the bloodstream
35
When we eat something, _____ release is triggered, activating _____ synthesis in the __ and ___
when we eat something, INSULIN release is triggered, activating GLYCOGEN synthesis in the LIVER and MUSCLE
36
After a meal, what happens to glucose concentration?
it drops
37
When our glucose concentration decreases after a meal, _____ release is decreased and ___ release is stimulated
INSULIN release is decreased and GLUCAGON release is stimulated
38
Epinephrine is released in response to ____ blood glucose
low
39
epinephrine stimulates....
glycogen breakdown in the liver
40
What are the target(s) of insulin?
liver, muscle, others
41
What is the origin of insulin?
pancreatic-beta cell
42
What are the target (s) of glucagon?
ONLY the liver
43
What is the origin and target of epinephrine?
origin = adrenal gland target= liver, muscle, others
44
What is a major consumer of glucose in the resting state?
skeletal muscle
45
During exercise, is glucose utilization increased or decreased?
increased 100 fold
46
What is another term for the state the body is in after eating a meal (when blood glucose conc drops)
the postprandial state
47
the regulation of muscle metabolism is largely ____
intrinsic
48
During exercise, blood flow is shunted away from the ___ and toward ____
away from the liver and towards muscle
49
In the post-exercise state, blood flow returns to the ____ and excess ___ accumulated by muscle glycolysis is converted to glucose by liver ______
blood flow returns to the LIVER and excess LACTATE accumulated by muscle glycolysis is converted to glucose by liver GLUCONEOGENESIS
50
Exercise causes a rise in intracellular...
calcium ions
51
_____ also increases cytosolic calcium ions
epinephrine
52
Cytosolic [Ca]+ concentration stimulates....
liver glycogen breakdown
53
calcium activates ___ breakdown which is important during ____
glycogen breakdown, exercise
54
The pentose phosphate shunt occurs in....
nearly all cells
55
The pentose phosphate shunt has 2 distinct contributions to the cell:
1. Partially oxidize glucose-6-phosphate and generate NADPH 2. Produce sugar phosphates including ribose phosphates
56
In the pentose phosphate shunt, NADPH is utilized as a....
reducing agent
57
in the pentose phosphate shunt, there is a __ stage and a __ stage
oxidative stage and nonoxidative stage
58
All of the reactions of the oxidative stage of the pentose phosphate shunt are metabolically _____
irreversible
59
give the formula for the oxidative stage of the pentose phosphate shunt
Glucose-6-P + 2NADP+ --> Ribulose-5-Phosphate + CO2 + 2NADPH
60
Give the enzymes that catalyze the 1st, 2nd, and 3rd steps of the oxidative stage of the pentose phosphate
1st step - glucose-6-pDH 2nd step - lactonase 3rd step - 6-p-gluconateDH
61
In the nonoxidative stage of the pentose phosphate shunt, all reactions are....
near equilibrium
62
In the nonoxidative stage, _______ undergoes 2 reactions:
ribulose-5-phosphate 1. Epimerase reaction (special type of isomerase) 2. Isomerase reaction
63
The intermediates of the nonoxidative stage can be incorporated into....
ribonucleotides
64
What are the 2 intermediates in the nonoxidative stage?
glyceraldehyde-P Fructose-6-p BOTH CAN ENTER GLYCOLYSIS WHICH GENERATES NO WASTE
65
The conversion to produce the 2 intermediates is performed by 2 enzymes:
transketolase transaldolase
66
in the transketolase enzyme, the cleavage occurs between the carbonyl and the ___ carbon
alpha carbon
67
in the transaldolase enzyme, the cleavage occurs between the carbonyl and the ___ carbon
beta
68
How is NADPH production and r5P distributed?
based on cellular demand.

Biochem Final (8 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2025 Bold Learning Solutions. Terms and Conditions