Exam 2 11/8 Howard Flashcards
(97 cards)
1
Q
What bodily system:
- Regulates function of every cell, tissue, organ
- Maintains status quo in face of alterations from environment
- “senses” disturbances and secretes hormones
A
Endocrine system
2
Q
What is the average energy expenditure for a sedentary adult?
A
2300 kcal/day
3
Q
What is basal metabolic rate (BMR)?
A
the amount of energy expended to survive (~ 60-70% of total energy)
4
Q
Fidgeting uses how much of our total energy expenditure?
A
20%
5
Q
Diet-induced thermogenesis and nonshivering thermogenesis use how much of our total energy expenditure?
A
5-15%
6
Q
When is the absorptive phase of metabolism?
A
2-3 hours to digest meal
7
Q
When is the postabsorptive state?
A
between meals, energy stores must be mobilized
8
Q
When is the fasting state?
A
Overnight, starvation
9
Q
What are the metabolic phases?
A
- absorptive
- postabsorptive
- fasting
- strenuous exercise or physical labor
10
Q
What enzyme catalyzes the reversible reaction between ATP and ADP?
A
Adenylate kinase
11
Q
Kinetic controls over catabolic pathways ensure that the [ATP]/([ADP][Pi]) ratio stays very __________
A
high (more ATP than ADP)
12
Q
How much ATP would you need to consume daily if you had to “eat” it?
A
100 lbs
13
Q
What is AMPK?
A
AMP-activated protein kinase
14
Q
When ATP is ______, AMPK is inactive
A
high
15
Q
When ATP is ______, AMPK is allosterically activated
A
low
16
Q
What is inhibited when AMPK is activated?
A
Anabolic metabolism - fatty acid synthesis, protein synthesis
17
Q
What is stimulated when AMPK is activated?
A
catabolic metabolism - fatty acid oxidation, glucose uptake
18
Q
Energy content of carbs
A
4 kcal/g
19
Q
Energy content of proteins
A
4 kcal/g
20
Q
Energy content of fat
A
9 kcal/g
21
Q
Energy content of alcohol
A
7 kcal/g
22
Q
analysis of __________________ can estimate the energy
requirements for different levels of exercise and evaluate food requirements for
maintaining healthy body mass
A
Respiratory gasses
23
Q
Where all can ATP come from?
A
- glucose
- amino acids
- FFAs from adipose
- ketone bodies from the liver
24
Q
What is the normal range of blood glucose
A
72-108 mg/100mL
25
What problems can arise from having low blood sugar?
- neurological problems
- coma
- death
26
What problems can arise from having high blood sugar?
- increased oxidative stress
- intracellular lipids
- lipotoxicity
- insulin resistance
27
Can glucose diffuse across cell membrane
No needs transporter
28
What are transporters of glucose across the cell membrane?
- sodium-glucose cotransporters (SGLTs)
- facilitated diffusion (GLUT) transporters
29
Where are SGLTs found
Apical membranes of simple epithelia (intestine and proximal tubules of the kidney)
30
What GLUT receptor has a low affinity and is found in the liver and pancreatic b cells?
GLUT 2
31
What GLUT receptors are found in all mammalian tissues and have a high affinity?
GLUT1, GLUT 3
32
What is the role of the GLUT2 receptor?
- pancreas: regulation of insulin
- liver: removes excess glucose from blood
(continuous uptake of glucose via glucokinase)
33
What is the role of the GLUT1/3 receptors?
Traps glucose in cell via hexokinase
34
What is the role of the GLUT4 receptor?
- insulin dependent GLUT
- central role in glucose tolerance
- insulin promotes update of glucose by muscle and its rapid phosphorylation to G6P
35
Where are GLUT4 receptors found?
Skeletal muscle, adipose tissue
36
What GLUT is insulin dependent?
GLUT 4
37
What drives glucose uptake in the liver?
glucokinase
38
What transports glucose to the blood from the liver?
Glucose 6 phosphatase
39
How much glycogen can the liver store?
100g
40
How much glycogen can the muscles store?
400g
41
Why is fat storage and mobilization critical for survival?
Amount of caloric storage of carbs is a small fraction of the total
42
____________ releases Free Fatty Acids from triglycerides carried by chylomicrons
Lipoprotein lipase
43
The ______ is the Major Metabolic Processing Center in Vertebrates
liver
44
Liver activity centers around
G6P
45
glucose-6-phosphate can be:
- converted to glycogen
- released as blood glucose
- used to generate NADPH and pentoses
- catabolized to acetyl-CoA for fatty acid synthesis
- energy production by oxidative phosphorylation
46
What is the brains preferred substrate?
glucose (can use ketone bodies during starvation)
47
What is the skeletal muscles (resting) preferred substrate?
fatty acids
48
What is the skeletal muscles (resting) energy reservoir?
glycogen
49
What is the skeletal muscles (active) preferred substrate?
Glucose from glycogen
50
What is the skeletal muscles (active) exported energy source?
Lactate
51
What is the heart muscles preferred substrate?
Fatty acids
52
What is the heart muscles energy reservoir?
Glycogen
53
What is the adipose tissue preferred substrate?
fatty acids
54
What is the adipose tissue energy reservoir?
triacylglycerol
55
What is the adipose tissue energy source export?
- fatty acids
- glycerol
56
What is the livers preferred substrate?
- amino acids
- glucose
- fatty acids
57
What is the livers energy reservoir?
- glycogen
- triacylglycerol
58
What is the livers energy source export?
- fatty acids
- glucose
- ketone bodies
59
20% of oxygen consumption is used by what organ?
Brain
60
Does the brain have fuel reserves
No
61
Sole fuel for the brain
Glucose
62
What organ makes glucose during fasting periods?
Liver
63
ketone bodies produced by liver from _________ during starvation
Fatty acids
64
Need ____ for muscle contraction
ATP
65
Muscles use ___% of oxygen consumption (at rest)
30% (from ffa, glucose, ketone bodies)
66
muscle oxygen consumption (exertion)
90
uses:
- 2% glycogen
- 0.08% phosphocreatine
- glucose via glycolysis
67
Glycolysis rapidly _______, causing muscle fatigue
Lowers pH
68
What is the main fuel for heart muscles?
fatty acids (can use glucose or ketone bodies)
69
________ levels dictate storage or mobilization of triglycerides
glucose
70
Alcohol metabolism is around ___ kcal/g
7
71
How can alcohol consumption lead to a fatty liver?
- Ethanol to acetate in liver (alcohol dehydrogenase)
- Acetate to Acetyl-CoA + NADH
- High NADH impairs TCA, fa oxidation; promotes fa synthesis
- Elevated liver triglycerides
- Fatty liver and cirrhosis
72
Pancreatic beta cells are associated with
Insulin
73
pancreatic alpha cells are associated with what?
glucagon
74
pancreatic PP cells are associated with what?
Pancreatic polypeptide
75
pancreatic delta cells are associated with what?
Somatostatin
76
What does insulin do?
- increases absorption of glucose
- induces storage of excess nutrients
- suppresses mobilization
- anabolic
77
How is insulin secretion stimulated?
- Glucose primary stimulus via GLUT2
- Glucose to glucose-6-P
- Oxidized makes ATP
- ATP closes ATP-sensitive K+ channel
- Depolarization opens voltage-gated Ca++ channels
- ↑ intracellular Ca++
- Exocytosis of granules
78
What are inhibitors of insulin secretion?
Epinephrine, norepinephrine
79
The insulin receptor is a _______ protein composed of two α- and two β-subunits
Tetrameric
- tyrosine kinase
- insulin binding (autophosphorylation)
80
What are the 2 broad signaling pathways for insulin receptors?
- MAPK pathway (cell growth, gene expression)
- PI-3K pathway (synthesis of lipids/proteins, survival)
81
Insulin promotes ____ reactions
Anabolic
82
What is the purpose of glucagon?
↑ blood glucose via liver glucose output
*↑ glycogenolysis
*↑ gluconeogenesis
*↓ glycolysis
*↓ glycogenesis
*↓ fa synthesis
(THINK CATABOLIC)
83
Primary target of glucagon
Liver
84
Stimulus for glucacon
Low blood glucose
85
____ opposes insulin action
Glucagon
86
Glucagon and __________ stimulate glycogen breakdown and inhibit glycogen synthesis
Epinephrine (liver and muscle)
87
fight or flight hormone that:
*Mobilizes large amount of glucose in liver
*Activates glycolysis in muscle cells
Epinephrine
88
glucocorticoids are __________ hormones
Steroid
89
Stress hormone
Cortisol
90
Cortisol and Glucocorticoids are primarily ____________- degrade macromolecules
Catabolic
91
What do Cortisol and Glucocorticoids do in the liver?
- stimulates gluconeogenesis
- increase glycogen synthesis
92
what does fructose 2,6 bisphosphate regulate?
positive on phosphofructokinase 1 and negative on fructose 1,6 bisphosphatase
93
High concentrations of fructose 2,6 bisphosphate stimulate what enzyme?
Phosphofructokinase 1 (promotes glycolysis)
94
Low concentrations of fructose 2,6 bisphosphate stimulate what enzyme?
Fructose-1,6-bisphosphatase (promoted gluconeogenesis)
95
What bifunctional enzyme activity can form Fructose-2,6 P2 from fructose-6-phosphate?
- PFK 2
- Fructose bisphosphatase 2
(controlled by phosphorylation)
96
In a fed state, (insulin, high blood glucose) what enzyme is active, Phosphofructokinase 2 or Fructose bisphosphatase 2?
PFK 2 (promotes PFK1 activity, glycolysis to use up glucose)
97
In a fasting state, (glucagon, low blood glucose) what enzyme is active, Phosphofructokinase 2 or Fructose bisphosphatase 2?
fructose bisphosphatase 2 (FBPase 2)
(promotes gluconeogenesis, inhibits glycolysis)
