Chapter 10 Carb Metabolism Flashcards
1
Q
Glycogen is the most abundant:
A
Animal carbohydrate
2
Q
Glucose oxidation provides _____ at _____/______ capable of supporting a wide variety of activities.
A
ATP, Rates, Quantities
3
Q
The most abundant animal carb is:
A
Glycogen
4
Q
On average a 154 lb man has how much glycogen stored?
A
15.5 ounces
5
Q
Glycogen stored in the muscles and liver in the:
A
Cytosol
6
Q
The glycogen in the cytosol is kept in:
A
Granules
7
Q
The granules contain:
A
The enzyme that controls synthesis/breakdown as well as enzymes that regulate the process
8
Q
UDP-glucose is the:
A
Activated form of glucose
9
Q
The activated form of glucose is called:
A
UDP-glucose
10
Q
Glycogen synthesis makes only:
A
α1-4 bonds
11
Q
Branching enzyme makes:
Branching enzyme breaks:
A
α1-6 bonds
α1-4 bonds
12
Q
How many enzymes build glycogen?
A
Two
13
Q
How many enzymes are involved in breaking down glycogen?
A
Two
14
Q
What breaks α1-4 linkages while transferring phosphates to liberated glucose molecules?
A
Phosphorylase
15
Q
What is the purpose of phosphorylase?
A
To break α1-4 linkages while transferring phosphates to liberated glucose molecules
16
Q
Phosphorylase is unable to:
A
Remove glucose residues from a branch point
17
Q
Debranching enzyme:
A
Catalyzes two reactions
18
Q
Debranching enzyme catalyzes two reactions:
A
- Transport of remaining glucosyl units of a branch to the end of another branch.
- Removes the remaining glucosyl unit by hydrolysis of the α1-6 bond
19
Q
Phosphorylase a is:
A
Active
20
Q
Phosphorylase b is:
A
Inactive but can be active
21
Q
Transitioning from phosphorylase a to phosphorylase b is done by:
A
Protein Phosphatase 1
(PP1)
22
Q
Transitioning from phosphorylase b to phosphorylase a is done by:
A
Phosphorylase kinase
23
Q
Protein Phosphatase 1 removes phosphates from:
A
Phosphorylase a
24
Q
Glycogenolysis rates are ____ in resting muscle.
A
Low
25
What makes only α1-4 bonds?
Glycogen synthase
26
What are the glycogenolysis rates in resting muscle?
Low
27
What activates glycogenolysis during exercise?
Epinephrine and glucagon
28
What happens to Pi concentrations during exercise?
Increase
29
What enzyme is inhibited by protein phosphatase I?
Phosphorylase kinase
30
What is the form of phosphorylase when it is inactive?
Phosphorylase b
31
What process leads to the activation of phosphorylase?
Phosphorylation by phosphorylase kinase
32
What inhibits phosphorylase activity?
Glucose
33
What happens to AMP and IMP during exercise?
They increase
34
What happens to ATP levels during exercise?
Decrease
35
What role does AMP have in relation to phosphorylase?
Allosteric activator
36
True or False: ATP acts as an allosteric inhibitor of phosphorylase.
True
37
What activates phosphorylase kinase?
Calcium activates phosphorylase kinase
## Footnote
Calcium plays a critical role in the activation of phosphorylase kinase, which is important for glycogenolysis.
38
How does exercise affect calcium signaling?
Exercise increases calcium signaling
## Footnote
The intensity of exercise can influence the levels of calcium in muscle cells, impacting various metabolic pathways.
39
Where is epinephrine released from?
Epinephrine is released from the adrenal medulla
## Footnote
The adrenal medulla is part of the adrenal glands and plays a key role in the body's fight-or-flight response.
40
What is the relationship between exercise intensity and epinephrine release?
More intense exercise leads to more epinephrine release
## Footnote
Higher exercise intensity triggers greater physiological responses, including increased secretion of epinephrine.
41
Fill in the blank: _______ is released from the adrenal medulla.
Epinephrine
42
What type of receptors does epinephrine bind to in muscle?
B-adrenergic receptors
43
What is the role of adenylate cyclase in the signaling pathway activated by epinephrine?
Converts ATP to cyclic-AMP (cAMP)
44
What is the reaction catalyzed by adenylate cyclase?
ATP → cAMP + PPi
45
What is the Gibbs free energy change (AG°') for the reaction involving adenylate cyclase?
1.6 kcal/mol
46
What metabolic process is activated as a result of the signaling pathway initiated by epinephrine?
Glycogenolysis
47
Fill in the blank: In muscle, epinephrine binds to _______.
B-adrenergic receptors
48
Epinephrine binds to:
β-adrenergic receptors
49
When epinephrine binds to β-Adrenergic receptors what is produced?
cAMP
50
The most common energy pathway is:
Glycolysis
51
The sole source of energy for erythrocytes is:
Glycolysis
52
Glucose 1-phosphate interacts with ____ to make glucose 6-phosphate.
Phosphoglucomutase
53
Glucose is phosphorylated by:
Hexokinase
54
When glucose interacts with hexokinase ______ is produced.
Glucose 6-phosphate
55
Glucose 6-phosphate interacts with ______ to make _____.
Phosphohexoisomerase
Fructose-6-phosphate
56
Glucose 6-phosphate interacts with phosphohexoseisomerase to produce:
Fructose 6-phosphate
57
Fructose 6-phosphate interacts with phosphofructokinase to produce:
Fructose 1,6-biphosphate
58
What happens to the glycolytic rate during exercise?
Rate increases > 100 fold during exercise
59
What are the two main ways to get more glucose substrate during exercise?
* Increased glucose uptake from blood
* Increased glucose production from glycogen
60
What is the role of phosphofructokinase (PFK) in glycolysis?
Rate Limiting enzyme of glycolysis
61
What is the effect of exercise on glucose uptake?
Increased glucose uptake from blood
62
What factors contribute to increased glucose uptake during exercise?
* Increased blood flow
* Increased glucose transporters: GLUT4
* Augmented GLUT4 translocation from intracellular vesicles
63
What is the efficiency of anaerobic fermentation compared to aerobic respiration?
Horribly inefficient: 2 or 3 ATP vs. 30 ATP in aerobic
64
How many ATP are produced specifically from anaerobic fermentation?
2 or 3 ATP
65
What enzyme is responsible for increasing glucose production from glycogen?
Phosphorylase
66
What makes only α1-4 bonds?
Glycogen synthase
67
ATP <-> cAMP +PPi yields how much energy?
ΔG = 1.6 kcal
68
ATP production in fermentation is fast or slow?
Fast. Just inefficient
69
Pyruvate is converted into____ during fermentation.
Lactate
70
In fermentation, NADH is oxidized to:
NAD
71
For glycolysis to continue, NAD+ must be:
Regenerated
72
For glycolysis to continue, _____ must be regenerated.
NAD+
73
For ____ to continue, NAD+ must be regenerated.
Glycolysis
74
Glycolysis shuts down without:
NAD+
75
Shuttling electrons from glycolytic NADH into mitochondria and through ETC (aerobic) is very:
Time consuming.
To slow for high intensity exercise
76
What uses Pyruvate to oxidize NADH?
Lactate Dehydrogenase
77
Lactate is used two different ways. In both steps lactate is ____ to ____. What are the two pathways for Pyruvate?
Completely oxidized through PDH, CAC, and ETC
Used to produce glucose through gluconeogenesis
78
When pyruvate is completely oxidized, what results?
CO2 and 12.5 ATP
79
What Is the purpose of the Cori Cycle?
Cycle of blood glucose -> pyruvate -> lactate (in muscle) -> pyruvate (in liver) -> blood glucose
80
Pyruvate Dehydrogenase Kinase (PDHK) at rest is a:
Pyruvate Dehydrogenase (PDH) inhibitor
81
Exercise is a ______ ________ activator.
Pyruvate Dehydrogenase (PDH)
82
The Krebs Cycle happens within the:
Mitochondrial Matrix
83
Products per Acetyl-CoA:
CO2
3 NADH
1 FADH2
1 GTP (~ATP)
84
Exercise increases the rate of the citric acid cycle.
True or false
True
85
During exercise, acetyl-CoA oxidation:
Increases 100-fold
86
The increase in acetyl-CoA oxidation during exercise is mostly due to:
Increase in acetyl-CoA availability
87
Rate limiting enzymes usually have the most:
Allosteric regulators
88
The rate limiting enzyme of the citric acid cycle is:
IDH (Isocitrate Dehydrogenase)
89
What is the main function of the Electron Transport Chain?
To pass electrons to O2 through a series of proton pumps
90
How does the earlier addition of electrons affect proton movement in the Electron Transport Chain?
More protons move to the intermembrane space
91
What is the Chemiosmotic Theory?
“…protons are expelled from the mitochondrion (matrix) only to return through ATP synthase" -Peter Mitchell
92
What is the ATP yield per NADH?
2.5 ATP
93
What is the ATP yield per FADH2?
1.5 ATP
94
What is the primary function of the electron transport chain according to the chemiosmotic theory?
To establish a proton gradient that will power the production of ATP by ATP synthase
## Footnote
This process is critical for cellular respiration and energy production.
95
What would happen to ATP production if protons could escape the innermembrane space without passing through ATP synthase?
ATP production would decrease or cease
## Footnote
This is because the proton gradient is essential for driving ATP synthesis.
96
What are Uncoupling Proteins (UCPs)?
Proteins in the mitochondrial matrix that play a role in energy metabolism
97
What effect does the general leakiness of the innermembrane have on protons?
It allows protons to escape the innermembrane space
## Footnote
This leakiness can impact the efficiency of ATP production.
98
What do UCPs do?
Act as channels for protons to leak back into the mitochondrial matrix, dissipating the proton gradient and releasing energy as heat.
This is known as uncoupling.
99
What is uncoupling?
The dissipation of the proton gradient that drives ATP synthesis
100
What happens to oxygen consumption during exercise?
Increases
101
How is oxygen consumption related to exercise intensity?
Proportional
102
What happens to NADH concentration during exercise?
Decreases
103
What effect does the decrease in NADH concentration have on PDH and the CAC?
“Lifts the brakes” on PDH and CAC
104
What process is sped up by exercise in relation to NAD+ and FAD?
Regeneration
105
What are NAD+ and FAD considered in glycolysis, pyruvate oxidation, and the CAC?
Indispensable oxidants
106
What does exercise increase in mitochondria?
Biogenesis
107
What is gluconeogenesis?
Production of new glucose from non-carbohydrates
108
What non-carbohydrate sources can be used in gluconeogenesis?
* Pyruvate
* Lactate
* Glycerol
* Amino acids
109
How is gluconeogenesis different from glycolysis?
Reversal of 7 of the 10 reactions of glycolysis.
Glycolysis breaks glucose, glyconeogenesis builds new glucose
110
Where does gluconeogenesis mostly occur?
Mostly in the cytosol, but starts in the mitochondrial matrix
111
How many ATP are required for gluconeogenesis?
6 ATP required
112
In which organs does gluconeogenesis primarily take place?
Mostly in the liver and kidneys
113
Does gluconeogenesis occur in muscle tissue?
No, it doesn't happen in muscle
114
Why doesn't gluconeogenesis occur in muscle?
Lack of glucose 6-phosphatase
115
Exercise increases gluconeogenesis in the:
Liver
116
What ensures that the blood has plenty of glucose?
Epinephrine and glucagon
117
What is hypoglycemia?
Low blood glucose concentration
118
What is the term for normal blood glucose?
Normoglycemia
## Footnote
Normoglycemia is essential for maintaining metabolic functions.
119
What does hyperglycemia refer to?
High blood glucose
## Footnote
Hyperglycemia can lead to various health issues, including diabetes.
120
Which organs or cells especially need glucose?
Brain, erythrocytes
## Footnote
The brain relies heavily on glucose for energy, while erythrocytes (red blood cells) use it for metabolism.
121
What is the postprandial state?
A physiological state after a meal involving digestion, absorption, and metabolism of nutrients.
## Footnote
In the postprandial state, blood glucose levels typically rise due to food intake.
122
Name the regulators of blood glucose levels.
Insulin, glucagon, epinephrine
## Footnote
These hormones work together to maintain blood glucose homeostasis.
123
Where are insulin, glucagon, and epinephrine produced?
Pancreas, adrenal glands
## Footnote
Insulin and glucagon are produced in the pancreas, while epinephrine is produced in the adrenal glands.
124
Why are insulin, glucagon, and epinephrine produced?
To regulate blood glucose levels
## Footnote
These hormones respond to changes in blood glucose and help maintain homeostasis.
125
What is the most important regulatory hormone of fuel metabolism?
Insulin
## Footnote
Insulin plays a critical role in managing the body's energy balance.
126
Which macronutrients does insulin regulate?
Carbohydrate, fat, and protein
## Footnote
Insulin affects the metabolism of all three major macronutrients.
127
What triggers the release of insulin?
Blood glucose concentration
## Footnote
Elevated blood glucose levels stimulate insulin secretion.
128
What hormone is released in response to blood glucose levels alongside insulin?
Glucagon
## Footnote
Glucagon works to increase blood glucose levels when they are low.
129
What is the primary function of insulin in relation to glucose?
Transport of glucose into muscle and fat
## Footnote
Insulin facilitates the uptake of glucose by tissues.
130
What is the goal of insulin's effects on biological fluids?
Decrease glucose concentration
## Footnote
Insulin aims to lower blood glucose levels.
131
What process does insulin increase in muscle and liver?
Glycogen synthesis
## Footnote
Glycogen synthesis is the conversion of glucose to glycogen for storage.
132
What effect does insulin have on glycogenolysis in muscle and liver?
Decreases
## Footnote
Glycogenolysis is the breakdown of glycogen to glucose.
133
What metabolic process does insulin speed up in the liver?
Glycolysis
## Footnote
Glycolysis is the breakdown of glucose for energy.
134
What effect does insulin have on gluconeogenesis in the liver?
Slows
## Footnote
Gluconeogenesis is the production of glucose from non-carbohydrate sources.
