Brainscape's Knowledge GenomeTM


Top Flashcards (Certified)
All Flashcards

BIOC 3300 > Week 2 => Glycogen and PPP, TCA cycle, and AA Degradation (Urea Cycle) > Flashcards

Week 2 => Glycogen and PPP, TCA cycle, and AA Degradation (Urea Cycle) Flashcards

1
Q

Glycogen linear chain

A

alpha 1,4-glycosidic bonds

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

Glycogen branch points

A

alpha 1,6-glycosidic bonds

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

Reducing end

A

Anomeric carbon (C1 of glucose)

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

Purpose of glycogen degradation in liver?

A

Maintaining blood glucose

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

Major energy storage molecule in the body?

A

Glycogen

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

Why do glycogenin-glucose chains serve as “primers” for glycogen synthase?

A

To extend with additional UDP-glucose units (alpha 1,4-linkages)

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

Precursor for glucose addition to glycogen chains?

A

UDP-glucose

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

Function of UDP-Glucose Pyrophosphorylase

A

Formation of glucose-glucose linkage in glycogen costs energy

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

What are branches important?

A
  • To increase the solubility of polymeric glucose
  • To allow multiple sites for glucose release (faster degradation)
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

Andersen disease

A

Mutation in liver branching enzyme. Abnormal glycogen structure. Failure to thrive, cirrhosis

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

Glycogen Degradation Enzymes

A
  • Phosphorolysis
  • Glycogen phosphorylase (regulated step)
  • Debranching enzyme
  • Phosphoglucomutase
  • Glucose-6-phosphatase
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

Cofactor for glycogen phosphorylase

A

Pyridoxal phosphate

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

Muscle enzyme used in glycolysis

A

Phosphoglucomutase

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

Liver enzyme used in glycolysis

A

Glucose-6-phophatase

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

McArdle Disease

A

Mutations in muscle glycogen phosphorylase. Impaired muscle glycogen degradation leads to muscle weakness and fatigue

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

2 activates of debranching enzymes

A

alpha 1,4-alpha1,4-glucantrasnferase and alpha 1,6-glucosidase

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

alpha 1,4-alpha1,4-glucantrasnferase

A

activity transfers triglucose from the branchpoint chain to another outer branch

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

alpha 1,6-glucosidase

A

activity releases the last glucose from the branchpoint

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

Forbes/Cori Disease

A

Mutations in liver and muscle debranching enzyme. Hypoglycemia during fasting, muscle weakness

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

Glycogen phosphorylase (GP) (form, activation)

A
  • Homodimer
  • activated by phosphorylation
  • Even when not phosphorylated, high levels of AMP can activate the enzyme allosterically
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

Glycogen Phosphorylase (GP) two levels of regulation

A

a) Local (cellular) energy status: AMP allosteric activator, glucose-6P and ATP overcome the activation
b) Tissue/organism level: Need for glucose during fasting (liver), need for glycolysis (muscle). Hormonal regulation of phosphorylation

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

Phosphorylase kinase reaction

A

phosphorylates glycogen phosphorylase –> more active form

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

Phosphoprotein phosphatase reaction

A

dephosphorylates glycogen phosphorylates –> less active form, but can still be allosterically activated by high ATP and/or G6P

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

Phosphorylase kinase is activated when ___

A

cAMP increases and protein kinase A is activated

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
25
Phosphoprotein phosphatase is activated ___
In response to insulin
26
Pentose phosphate pathway substrates
Glucose-6-phosphate, NADP+
27
Pentose phosphate pathway products
NADPH, Co2, Pentose (Ribulose-5-phosphate)
28
Pentose phosphate pathway oxidative stage:
Synthesis of NADPH and pentose sugar
29
What happens to pentose that are not used for nucleotides?
They are metabolized in glycolysis
30
Glucose-6-phosphate dehydorgenase
Catalyzes first step of the PP, inhibited by NADPH
31
NADPH
* Required for cholesterol and fatty acid synthesis * Required for regeneration of glutathione (antioxidant)
32
Pyruvate dehydrogenase complex
Oxidation of pyruvate to acetyl-CoA
33
What is "Coenzyme A" a derivative of ?
ADP and pantothenic acid (from vitamin B5)
34
What functional group is on Free coenzyme A
a thiol group (can form thioester bonds)
35
CoASH
Coenzyme A with SH-group
36
CoA
Coenzyme A esterified to an acyl group
37
Pathways Acetyl-CoA can enter?
* Oxidation in TCA cycle (in mitochondria) * Precursor for many larger metabolites (in cytosol)
38
Thiamine pyrophosphate (TPP)
Cofactor for decarboxylations of ketoacids
39
Lipoamide
Derived form lipoic acid, acyl group and electron carrier
40
Flavin coenzymes FAD & FMN
Derived form riboflavin (vitamin B2), electron transfer reactions via reduction of ring system
41
Coenzymes in PDH and other dehydrogenases
1) Thiamine pyrophosphate (TPP) 2) Lipoamide 3)Flavin coenzymes FAD & FMN
42
Pyruvate Dehydrogenase (PDH) Complex
* Complex of 3 enzymes and 5 coenzymes * Contains up to 60 subunits (depending on species) that convert pyruvate to acetyl-CoA
43
3 enzymes in PDH
1) Pyruvate dehydrogenase/decarboxylase 2) Dihydrolipoamide transacetylase 3) Dihydrolipoamide dehydrogenase
44
5 cofactors of PDH
1) TPP 2) Lipoic acid 3) Coenzyme A (CoA) 4) Flavin adenine dinucleotide (FAD) 5) nicotinamide adenine dinucleotide (NAD+)
45
PDH allosteric regualtion
PDH is allosterically inhibited by Acetyl-CoA and NADH (product inhibition)
46
Regulation of PDH activity by phosphorylation
PDH kinase phosphorylates PDH and inactivates PDH. PDH phosphatase dephosphorylates PDH and activates PDH
47
Reaction 1 of Citric Acid Cycle
Citrate synthase adds the acetyl group from acetyl-CoA to oxaloacetate (irreversible)
48
Reaction 2 of Citric Acid Cycle
Isomerization to isocitrate (reversible)
49
First decarboxylation (citric acid cycle)
Isocitrate dehydrogenase
50
Second decarboxylation (citric acid cycle)
alpha-ketoglutarate dehydrogenase
51
Succinyl Synthetase
Formation of 1 GTP
52
Succinate dehydrogenase
Oxidation of succinate to fumarate coupled to reduction of ubiquinone Q to ubiquinol QH2.
53
Fumerase
Hydration of fumarate to malate
54
Malate dehydrogenase
Oxidations of malate to oxaloacetate coupled to reduction to NAD+ to NADH
55
What does TCA serve as a source for?
both energy and of metabolic intermediates
56
Anaplerotic reactions
Replenishment of TCA cycle intermediates
57
Processes that replenish intermediates in the cycle:
a) Oxaloacetate b) Malice enzyme c) Transamination reactions
58
Cataplerotic reactions
TCA cycle intermediates are precursors of other molecules
59
Glucogenic
can be converted to glucose
60
Metabolites that can be converted to glucose through gluconeogenesis
Glucogenic
61
Metabolites that cannot be converted to glucose through gluconeogenesis
Ketogenic
62
Nonessential amino acids
alanine, arginine, asparagine, aspartic acid, cysteine, glutamic acid, glutamine, glycine, proline, serine, and tyrosine
63
Essential amino acids
Histidine, Isoleucine, Leucine, Lysine, Methionine, Phenylalanine, Threonine, Tryptophan, Valine
64
Transamination Reactions
Amino groups can be transferred from molecule to molecule. Involve enzymes called transaminases or aminotransferases (same enzyme)
65
Transamination examples
Alanine Aminotransferase (ALT) and Aspartate Aminotransferase (AST)
66
Prosthetic group of all transaminases?
Pyridoxal phosphate PLP
67
Reductive Amination
Synthesis of amino acid
68
Oxidative Deamination
Degradation of amino acid
69
Glutamate dehydrogenase
Catalyze glutamate and alpha-ketoglutarate interconversion by reductive amination/oxidative deamination
70
What reaction uses free ammonium?
Glutamine synthetase reaction
71
What reaction releases ammonium?
Deamidation of glutamine to glutamate
72
Glutaminase
converts glutamine to glutamate (deamidation)
73
Where are most amino acids degraded?
The liver
74
Amino acid oxidation in humans occurs mainly in three metabolic states
1) Basal 2) High protein diet 3) starvation or diabetes mellitus 4) Lack of essential amino acids
75
Basal metabolic state
Amino acids generated by continual biosynthesis and degradation of cell proteins
76
High protein diet metabolic state
In take exceeds requirement for protein synthesis
77
Starvation or diabetes mellitus
Carbohydrate is not available or is improperly utilized
78
Lack of essential amino acids metabolic state
Protein synthesis is impaired, other amino acids are degraded
79
Negative N(nitrogen) balance: N (in) < N (out)
* starvation * serious illness * insufficient essential aa
80
Positive N(nitrogen) balance: N (in) > N (out)
* Growth * Pregnancy * Recovery illness or starvation
81
Forms of excreted excess nitrogen
* Ammonia * Urea * Uric acid
82
Urea cycle direct substrates
Aspartate and carbamoyl phosphate (from ammonia and bicarbonate)
83
Urea cycle products
Urea and fumerate
84
Carbamoyl phosphate synthetase
controls urea production (investment of energy to generate a transferable amino group)
85
Mitochondrial carbamoyl phosphate synthetase CPS1 enzyme tunnel shielding and channeling
Shielding: protect reactive intermediate Channeling: prevent loss of intermediates concentrate them locally
86
Urea cycle 5 enzymes
1) Carbamoyl phosphate synthase 1 2) Ornithine transcarbamoylase (OTC) 3) Arginosuccinate synthetase (ASS) 4) Arginosuccinate lyase 5) Arginase
87
What activates CSP1?
N-acetylglutamate (NAG) => increases CSP1 affinity for ATP
88
Processes for detoxification for NH4+
through glutamine synthetase or glutamate dehydrogenase
89
Aspartate-arginosuccinate shunt
Pathway linking TCA cycle and urea cycle

BIOC 3300 (11 decks)

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