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Intro To Metabolism Flashcards

1
Q

Devoted to the capture of useful energy from high-energy compounds, and to the breakdown of compounds to simpler constituents

A

Catabolic Pathways

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2
Q

The small molecules that are the reactants and products of a reaction are called

A

Metabolites, enzymes, and energy

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3
Q

Signal transduction pathways regulate

A

Metabolism

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4
Q

Signaling molecules become activated by modifications such as

A

Phosphorylation

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5
Q

A major role of the hormones involved in metabolic homeostasis is to maintain blood glucose levels above

A

60mg/100mL

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6
Q

It is also important that fasting glucose levels remain below

A

100mg/dL

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7
Q

The stored form of fuels, in particular adipose tissue, directly correlated with

A

Leptin and Insulin Levels

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8
Q

Sense blood glucose and use this information to regulate food intake

A

Glucoreceptors in the hypothalamus

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9
Q

Stimulates anabolic metabolism

A

mTOR signaling pathway

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10
Q

The mechanistic target of rapamycin (mTOR) signaling pathway controls

A

Metabolism and cell growth

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11
Q

Stimulates multiple anabolic pathways in the response to the presence of nutrients and growth factors such as insulin

A

mTOR protein complex 1 (mTORC1)

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12
Q

Controls a number of mechanisms involved in protein, lipid, and nucleotide synthesis to produce macromolecules required for cell growth

A

mTORC1

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13
Q

mTOR also negatively regulates catabolic processes such as

A

Autophagy and lysosome biogenesis

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14
Q

Which signaling pathway stimulates catabolic metabolism?

A

AMPK signaling pathway

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15
Q

Activated when metabolic demand exceeds metbolic supply, resulting in a decrease in the ATP/ADP ratio

A

AMP-activated Protein Kinase

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16
Q

Together, act as nutrient and energy sensors and regulate metabolism in conjunction with hormones

A

mTORC1 and AMPK

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17
Q

Metabolic pathways generate substrates that are used as post-translational modifications to control

A

Signal Transduction

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18
Q

Glycosylation, acetylation, mehtylation, and prenylation change activity, localization, and stability of

A

Target proteins

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19
Q

Also modify DNA and histones, leading to epigenetic alterations that influence gene expression and chromatin structure

A

Acetylation and methylation

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20
Q

Insulin binding to the insulin receptor triggers the PI3K/mTOR pathway, thus promoting

A

Anabolic Metabolism

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21
Q

Insulin is secreted into the portal vein, but almost half is degraded before leaving the

A

Liver

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22
Q

Serum insulin levels normally begin to rise within 10 minutes after ingestion of food and reach a peak in

A

30-45 minutes

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23
Q

Permit a rate of glucose influx that is proportional to the blood concentration in the physiological range

-In beta cells

A

GLUT2

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24
Q

The rate limiting step for glucose metabolism in the beta cell and the major mechanism of glucose sensing production of ATP

A

Glucose phosphorylation by Glucokinase (Hexokinase)

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25
Inhibits the ATP-sensitive K+ channel and leads to depolarization, while also opening Ca2+ channel, leading to insulin exocytosis
Glucose phosphorylation by Glucokinase (Hexokinase)
26
Insulin gene expression and islet cell biogenesis are dependent on several transcription factors that are specific to the
Pancreas, liver, and kidney
27
Bind to K channels to block activity and promote insulin release
Sulfonylurea drugs
28
The most important hormone coordinating the use of fuel
Insulin
29
The primary hormone that orchestrates fuel use and storage during the fed state
Insulin
30
Insulin is synthesized in the beta cells as a prepro-hormone consisting of peptides
A, B, and C (a connecting peptide)
31
About 5-10% of the final secreted product is still in the form of -no insulin activity
Proinsulin
32
Genes coding for insulin are transcribed to mRNA in the
Nucleus
33
mRNA then moves into the cytoplasm and translation occurs with formation of an N-terminal hydrophobic signal sequence that targets the nascent chain into the
ER
34
Further elongation of the nascent chain into the lumen of the ER results in the formation of
Preproinsulin
35
The signal sequence is then cleaved, forming
Proinsulin
36
Proinsulin is transported from the ER to the Golgi where it is cleaved, forming the
Insulin and C-peptide
37
Insulin and C-peptide are stored in
Secretory granules
38
Secretory granules are secreted by exocytosis, releasing
Insulin and C-peptide
39
A good indicator of insulin production due to its longer half life
C-peptide
40
Used to differentiate the cause of high insulin in patients -i.e. increased endogenous production vs exogenous overdose
C-peptide levels
41
Activates protein kinases such as Akt that negatively regulate repressors of the anabolic effects of insulin
Insulin signaling
42
Repressing these factors (such as FOXO, TSC2, and GSK3) promotes
Glucose metabolism and the other effects of insulin
43
In the liver, insulin stimulates glucose uptake by -Leads to subsequent glycolysis
GLUT-2
44
Once hepatic glycogen stores are replenished (80-100g), excess glucose is used for the synthesis of
Triglycerides
45
The glucose that is not captured by the liver contributes to the postprandial rise in
Peripheral Glucose levels
46
Refers to the ability of an individual to minimize the increase in blood glucose concentration after a meal
Glucose tolerance
47
A primary way by which insulin promotes glucose tolerance is the activation of
GLUT4 in skeletal muscle
48
Stimulates the translocation of GLUT4 transporters to the cell membrane
Insulin
49
Insulin also stimulates GLUT4 dependent uptake of glucose and subsequent glycolysis in
Adipose tissue
50
Utilizes glycolysis for energy needs, but also for generation of glycerol-3-P required for reesterification of FFAs into triglycerides
Adipose TIssue
51
Stimulates the expression of LPL within adipose, promoting the release of FFAs from chylomicrons
Insulin
52
Under resting conditions, Rab10 is constitutively inactivated by TBC1D4/AS160 through its
GAP activity
53
Inactive Rab10 is then unable to target the
GLUT4 containing vesicles
54
Upon insulin stimulation, the insulin receptor phosphorylates
IRS-1
55
IRS-1 then activates
PI3K
56
Produced by PI3K at the plasma membrane where it activates Akt/PKB
PIP3
57
The activated Akt phosphorylates a variety of target molecules including
TBC1D4
58
Phosphorylated TBC1D4 then loses its GAP activity, and thus Rab10 is activated, promoting translocation of
GLUT4 to the plasma membrane
59
Glucagon and Epinephrine bind to
G-protein coupled receptors
60
Epinephrine and glucagon both function to control
Glycogen metabolism
61
Glucagon and epinephrine both trigger the production of cAMP and the activation of
PKA
62
Has epinephrine receptors but no glucagon receptors
Muscle
63
In the muscle, glycogen metabolism stimulated by Epi produces
Lactate
64
In the liver, epinephrine and glucagon stimulate the breakdown of glycogen to
Glucose phosphate
65
Represent the primary hormones that induce the mobilization of energy stores and new synthesis of glucose and ketone bodies during the fasting state
Glucagon and catelcholamines
66
Glucagon and catecholamines also promote proteolysis and the release of
Amino acids
67
Activation of the pituitary-adrenal axis is a prominent neuroendocrine response to
Stress
68
Stimulation of this axis results in hypothalamic secretion of
Corticotrophin-Releasing Factor (CRF)
69
CRF then stimultes the pituitary to release
ACTH
70
Which part of the hypothalamus is responsible for the integrated response to stress?
Paraventricular nucleus
71
Which three things mediate much of the neurogenic stimulation of CRF production
Norepi, Seratonin, and Acetylcholine
72
Binds to G-protein coupled receptor to manage acute stress
Epinephrine
73
The same signaling pathways can be used for both
Glucagon and epinephrine
74
Epinephrine responds to
Stress
75
Glucagon responds to
Low blood sugar
76
Caffeine, theophylline, and other members of the methylxanthine group of compounds inhibit
Phosphodiesterase
77
Inhibiting phosphodiesterase leads to an increase in cellular levels of
cAMP
78
Cortisol is present in the blood bound to
Corticosteroid-binding globulin (CBG)
79
When cortisol binds its receptor, the steroid-receptor complex enters the nucleus as a dimer and binds to the
Glucocorticoid Response Element (GRE)
80
GH stimulates growth primarily through the regulation of the growth-promoting hormone
IGF
81
Also has metabolic functions such as raising blood glucose by decreasing peripheral tissue utilization
GH
82
Promotes lypolysis and thus increases the availability of glycerol and FFas as fuel for muscle work
GH
83
During periods of metabolic demand, GH shunts the metabolic pathways from glycogenolysis to the metabolism of FFAs into
Acteyl CoA
84
The only proglycemic hormone
GH
85
GH directly blocks glucose uptake by skeletal muscle, and thus promotes
Insulin resistance
86
Increase the basal rate of oxygen consumption and heat production
Thyroid hormones
87
Potentiates stimulatory effects of epi, norepi, glucagon, cortisol, and GH on gluconeogenesis, lipolysis, ketogenesis, and proteolysis
T3
88
The overall metabolic effect of thyroid hormone is accelerating the response to
Starvation
89
How many types of intracellular thyroid hormone receptors are there?
Two
90
The unoccupied thyroid hormone receptor is bound to DNA and it represses
Transcription
91
Therefore, thyroid hormone receptor acts as a repressor in the absence of
Thyroid hormone
92
What is the first compound common to the catabolism oarbohydrates, lipids, proteins, and ethanol?
Acetyl CoA
93
Can humans synthesize fatty acids from glucose?
No
94
Which 4 amino acids can glucose NOT synthesize?
Leu, Ile, Lys, and Phe

GI (59 decks)

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