Brainscape's Knowledge GenomeTM


Top Flashcards (Certified)
All Flashcards

Medical Biochemistry > Ch. 20: Perturbations Of Energy Metabolism: Obesity & DM > Flashcards

Ch. 20: Perturbations Of Energy Metabolism: Obesity & DM Flashcards

1
Q

What is anabolism?

A

Synthesis of new molecules (requires energy)

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

What is catabolism?

A

Breakdown of large molecules ➡️ smaller ones (yields energy)

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

What is intermediary metabolism?

A

All changes in a food substance from absorption ➡️ excretion

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

How many kcal/g are there in: Carbs? Protein? Fat? Alcohol?

A

Carb: 4 kcal/g
Protein: 4 kcal/g
Fat: 9 kcal/g
Alcohol: 7 kcal/g

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

What is basal metabolic rate (BMR)?

A

Vital energy needs of the body during physical, emotional, and digestive rests

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

In what situations is BMR ⬆️?

A

Hyperthyroidism, fever, Cushing’s syndrome, adrenal tumors, anemia, leukemia, polycythmia, cardiac insufficiency, injury

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

In what situations is BMR ⬇️?

A

Hypothyroidism, starvation, malnutrition, hypopituitarism, hypoadrenalism (Addison’s), anorexia nervosa

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

What is the role of the hypothalamus in mediating feeding behavior?

A

Integrates signals for energy storage & dissipation

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

What is the structure of AMP-activated protein kinase (AMPK)?

A

Heterotrimeric protein complex:

1) Catalytic alpha-subunit
2) Regulatory beta & gamma subunits

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

How is AMPK activated? Function?

A

⬆️ [AMP]/ATP ➡️ ➕ AMPK ➡️ ATP synthesis

AMPK also ➕ by: Metformin, Troglitazone, LKB1, CaMKKbeta, other kinases

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

What are the negative allosteric regulators of AMPK?

A

Phosphocreatine

Glycogen

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

What does AMPK activate?

A

1) p53 ➡️ ⬆️ cell cycle arrest ⬇️ cancer risk
2) TSC2 ➡️ ➖ mTOR ➡️ ⬇️ protein synthesis/cell survival
3) EF2K ➡️ ⬇️ protein synthesis

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

What does AMPK inhibit?

A

1) ACC1/FAS ➡️ ⬇️ FA synthesis
2) ACC2 ➡️ ⬆️ FA oxidation
3) HMG-CoA reductase ➡️ ⬇️ sterol synthesis

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

What is leptin? Function?

A

Long term regulator of energy metabolism, hunger & satiety

Acts in afferent signal pathway of negative feedback loop ➡️ regulate size of adipose tissue & energy balance

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

What cells synthesize leptin?

What ⬆️ leptin synthesis? ⬇️ leptin synthesis?

A

Adipocytes

⬆️ leptin synthesis: insulin, glucocorticoids, estrogens
⬇️ leptin synthesis: beta-adrenergic agonists

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

What does leptin inhibit? What is its function as a regulator?

A

PPAR-gama2: regulates conversion of preadipocyte to adipocytes ➡️ ⬇️ blood glucose

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

Why do obese individuals have ⬆️ leptin levels?

A

Resistance/defect in leptin receptors

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

During starvation, ⬇️ [leptin]

What does this cause?

A

hypothalamus produces neuropeptide Y ➡️ transported to PVN (in brain) ➡️:

1) ⬆️ appetite
2) ⬇️ energy expenditure
3) ⬇️ temp
4) ⬇️ reproductive function
5) ⬆️ parasympathetic activity

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

When ⬆️ [leptin], what does this cause?

A

MSH (melanocyte stimulating hormone) binds to MC4-R ➡️:

1) ⬇️ appetite
2) ⬆️ energy expenditure
3) ⬆️ sympathetic activity

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

What are the appetite decreasing (satiating) mediators?

A 
PYY
CCK
Oxyntomodulin
Insulin
Leptin
CNS mediators (serotonin, dopamine)
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

What are the appetite stimulating (orexigenic) mediators?

A 
Ghrelin
⬇️ leptin
CNS mediators (galanin, opioids)
Glucocorticoids
Norepinephrine
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

BMI range for overweight? Obese?

A

Overweight: 25-29.9

Obese: greater than or equal to 30

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

Obesity is a risk factor for development of what conditions?

A

Diabetes mellitus
Hypertension
Heart disease

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

What are short term regulators of hunger & satiety?

A

Plasma levels of glucose & a.a.

CCK & other hormones

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
25
What is ghrelin? Where is secreted from?
Only known appetite stimulating hormone Stomach
26
What condition can congenital human leptin deficiency cause?
Early onset obesity (defective leptin receptor gene)
27
What is Prader-Willi syndrome? What causes it?
Most prevalent form of dysmorphic genetic obesity Absence of paternally derived PWS/AS region of chromosome 15
28
Angelman syndrome (similar to Prader-Willi): what causes it?
Inherited chromosome 15 deletions from mother
29
What drugs can be used to treat obesity? (Appetite suppression)
Sibutramine | Orlistat
30
At rest, what energy sources does smooth muscle use to maintain cellular integrity?
FA catabolism | BCAAs
31
What is the energy source during exercise generating max power?
ATP & Phosphocreatine ➡️ glycolysis from glycogen
32
What is the energy source during high intensity endurance exercise?
Phosphocreatine ➡️ glycogenolysis (muscle & liver) ➡️ ⬆️ aerobic oxidation, FA & plasma glucose utilization, BCAA oxidation
33
What is the energy source during low level non-fatiguing exercise?
Aerobic oxidation of FAs, glucose, BCAAs No depletion of phosphocreatine & minimal muscle glycogen used
34
What is metabolic homeostasis? What regulates it?
Tendency for biological systems to maintain constant chemical conditions in their internal environments Endocrine system
35
How are major fuels (CHO, lipid, pro) used to maintain energy requirements?
1) maintain blood glucose level w/in normal limits 2) maintain optimal glycogen supply 3) maintain optimal pro supply
36
How is body weight regulated?
1) food intake 2) heat loss 3) energy expenditure (e.g. exercise)
37
General description of the heart & its energy use/requirements?
Scavenger: uses anything for energy (FAs, glucose, KBs)
38
General description of the brain & its energy use/requirements?
Selfish: uses majority of glucose, also uses KBs in starvation
39
General description of the liver & its energy use/requirements?
Unselfish: provider of nutrients to other tissues, "mother figure" Uses fat (not glucose) for energy
40
Main metabolic roles of liver?
1) 1st to receive nutrients from intestines (EXCEPT fats) 2) Deliver bile to intestines (cholesterol homeostasis) 3) Main site of glycogen deposition & blood glucose maintenance 4) important in lipid, protein, & nitrogen homeostasis 5) supplies energy via FA oxidation
41
Difference between brown adipose & white adipose?
Brown adipose: produce heat; contain lots of mitochondria White adipose: export triacylglycerol as FAs
42
Main metabolic roles of skeletal muscle?
1) contains most of body's nonlipid fuel 2) has 4x more glycogen than liver (but less concentrated) 3) lacks G6P ➡️ can't be a source of blood glucose 4) starvation: provides a.a. (main carbon source for glucose homeostasis) 5) Part of Cori cycle
43
Main metabolic roles of kidneys?
1) a.a. homeostasis | 2) gluconeogenesis (fasting)
44
Main metabolic roles of blood/body fluids?
1) contains simple CHOs, a.a. (⬆️ ala, gln), anions, TCA intermediates, toxic metabolites, macromolecules 2) has albumin: transports FAs, drugs, toxic metabolites, indicator of liver function, osmotic regulator 3) has lipoproteins
45
What hormones does the endocrine pancreas secrete? What cell types secrete each hormone?
``` Secretes: insulin (beta cells) glucagon (alpha cells) somatostatin (delta cells) pancreatic polypeptide (F cells) ```
46
Structure of insulin? Steps of insulin biosynthesis?
A & B chain + C peptide preproinsulin ➡️ proinsulin ➡️ packaged into secretory granules ➡️ conversion to insulin + C peptide
47
What is lispro insulin? How is it structurally different from other insulin?
Artificial, no dimer formation, insulin used to treat diabetes 28Pro29Lys on B chain are switched
48
How can you measure how much insulin the body is making?
Measure C peptide
49
What things ➕ insulin secretion?
Glucose, a.a., glucagon-like peptide, acetylcholine, beta-adrenergic agents, sulfonylurea
50
What things ➖ insulin secretion?
Somatostatin, alpha-adrenergic agents, diazoxides
51
What are the biological actions of insulin?
1) ➕ fuel storage & protein synthesis (➖ breakdown) | 2) ➕ glucose uptake into muscle & adipose via GLUT4
52
Describe the structure & function of the insulin receptor.
Heterotetramer (2 alpha, 2 beta subunits) tyrosine kinase (insulin binds to extracellular alpha subunits ➡️ intracellular domain of beta subunits self-phosphorylate)
53
What conditions involve problems with the insulin receptor?
Leprechaunism/Donohue syndrome: ⬇️ functionality of insulin receptor Type A insulin resistance (autoimmune disease, mutation in insulin receptor genes)
54
What are the short acting insulins?
Lispro Aspart Glulisine
55
What are the long-acting insulins?
Glargine | Detemir
56
Steps of insulin secretion?
Glucose enters beta cells (via GLUT1 and 2) ➡️ convert to G6P (via glucokinase) ➡️ ATP production ➡️ ➖ ATP-sensitive K+ channel ➡️ ⬇️ K+ efflux ➡️ membrane depolarization ➡️ Ca2+ influx ➡️ insulin release from granules
57
How do sulfonylurea and diazoxides affect insulin secretion?
Sulfonylurea: inhibits K+ channel via sulfonylurea receptors (SUR) ➡️ ➕ insulin secretion Diazoxides: keeps K+ channels open via SUR ➡️ ➖ insulin secretion
58
How does somatostatin affect insulin secretion?
➖ Ca2+ influx ➡️ ➖ insulin secretion
59
How does acetylcholine affect insulin secretion?
➕ Gq protein ➡️ ➕ phospholipase C-IP3-Ca2+ ➡️ ⬆️ insulin secretion
60
How does epi & norepi affect insulin secretion?
Bind to alpha-adrenergic receptor sites ➡️ ➕ Gi protein ➡️ ➖ adenylate cyclase ➡️ ⬇️ cAMP ➡️ ⬇️ protein kinase A activity ➡️ ⬇️ insulin secretion
61
How does glucagon-like peptide 1 (incretin) affect insulin secretion?
➕ Gs protein ➡️ ➕ adenylate cyclase ➡️ ⬆️ cAMP ➡️ ⬆️ protein kinase A activity ➡️ ➕ insulin secretion
62
What does glucagon stimulate?
⬆️ in blood glucose: ➕ glycogenolysis, gluconeogenesis, ketogenesis in liver ➕ lipolysis of TG in adipocytes
63
What enzymes ➕ with ⬆️ insulin/glucagon ratio?
Glucokinase, citrate cleavage enzyme, acetyl-CoA carboxylase, HMG-CoA reductase, pyruvate kinase, PFK1, PFK2, F-2,6-BPase ➡️ glycolysis
64
What enzymes ➕ with ⬇️ insulin/glucagon ratio?
G6Pase, PEP carboxylase, F-1,6-BPase ➡️ gluconeogenesis
65
Under what circumstances is glucagon secreted? Under what circumstance is glucagon secretion inhibited?
Secreted: hypoglycemia, ⬇️ blood glucose, ⬆️ blood a.a., exercise Inhibited: ⬆️ blood glucose
66
What does somatostatin do in the pancreatic islets? Pituitary gland? Gut?
Islets: ➖ insulin & glucagon secretion Pituitary gland: ➖ GH & TSH release Gut:➖ gastrin & motilin secretion
67
When is pancreatic polypeptide secreted? What is its potential effect on pancreas?
Secreted in response to fuel ingestion May affect pancreatic exocrine secretion of HCO3- and proteolytic zymogens
68
What are the 2 principal energy stores?
Triacylglycerol & proteins
69
CHO digestion & absorption: compare glucose, galactose, & fructose?
Glucose & galactose ➡️ direct into blood via enterocytes (Na+ dependent co-transport) Fructose: absorbed by specific system (GLUT V) ➡️ some metabolized in enterocytes, rest enters portal blood to be used by liver & kidneys
70
Glucose tolerance (in fasting state): consume 75g glucose and monitor blood glucose over time What are the values for normal & diabetes?
Normal: < 110 mg/dL Diabetes: > or equal to 200 mg/dL
71
How do catecholamines trigger utilization of hepatic glycogen?
Catecholamines released w/⬆️ stress & high intensity exercise ➡️ ➕ Ca2+ release from ER & ➕ phosphorylase kinase ➡️ ➕ glycogen phosphorylase ➡️ glycogenolysis
72
What enzyme is the key step in regulation of glycolysis in skeletal muscle? What inhibits this enzyme? What activates it?
PFK ➖: ATP ➕: Pi, 5'-AMP, ADP
73
What allosterically regulates skeletal muscle phosphorylase?
5'-AMP
74
What are the 3 sources used as substrates for gluconeogenesis?
Glycerol Lactate Glucogenic a.a.
75
What things regulate gluconeogenesis?
➕, acute: Glucagon & epinephrine ➕, chronic: glucocorticoid (cortisol) ➖: absence of insulin

Medical Biochemistry (23 decks)

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