Exam 3 Integration of Metabolism

Question 1

aas are _ into acetyl coA

Answer 1

deaminated

Question 2

carbohydrates are digested into monosaccharides where they enter _ to make acetyl coA

Answer 2

glycolysis

Question 3

FAs undergo _ into acetyl coA

Answer 3

B-oxidation

Question 4

we can have glycogen metabolism via the key molecule _

Answer 4

G6P

Question 5

formation of pyruvate from _ via _

Answer 5

from G6P via glycolysis or gluconeogenesis

Question 6

formation of ribose-5-phosphate from _ via _

Answer 6

from G6P via PP pathway

Question 7

formation of acetyl coA from _ via _

Answer 7

pyruvate via pyruvate dehydrogenase

Question 8

formation of lactate from _ via _

Answer 8

from pyruvate via lactate dehydrogenase (exercising muscle)

Question 9

formation of alanine from _ via _

Answer 9

pyruvate via transaminase

Question 10

formation of OAA from _ via _

Answer 10

pyruvate via TCA cycle

Question 11

formation of CO2 from _ via _

Answer 11

acetyl coA via TCA cycle

Question 12

formation of ketone bodies from _

Answer 12

from excess acetyl coA (ketone body metabolism)

Question 13

formation of FAs from _

Answer 13

acetyl coA (building block)

Question 14

preferred energy source of RBCs?

Answer 14

glucose because has no other organelles

Question 15

preferred energy source of brain?

Answer 15

glucose and ketone bodies under conditions of starvation

Question 16

preferred energy source of adipose tissue?

Answer 16

glucose and FAs

Question 17

preferred energy source of liver?

Answer 17

FAs; liver may be a “hub” for all energy sources but for itself, prefers FAs for B-oxidation for its own energy needs (for liver cells)

Question 18

preferred energy source of muscles?

Answer 18

glucose, FAs, aas

Question 19

why is the liver the “MVP” of metabolism?

Answer 19

• processes most incoming nutrients via HPV
• responds quickly to dietary conditions (makes sure every organ/tissue gets its nutrition and provides constant nutrient level in the blood)
• synthesizes and secretes proteins for rest of body (plasma proteins, antibodies, acute phase proteins)
• processes toxins and wastes

Question 20

aas go directly to the liver through _ after absorption

Answer 20

portal vein

Question 21

liver uses aas to make:

Answer 21

proteins, biosynthesis of nitrogen-containing molecules, for gluconeogenesis, or for feul

Question 22

adipose tissue synthesizes and stores _ as signaled by _

Answer 22

synthesizes and stores TAGs as signaled by insulin (fed state)

Question 23

adipose tissue releases _ + _ as signaled by _

Answer 23

releases FAs + glycerol as signaled by glucagon/epinephrine (hunger, exercise)

Question 24

FAs are transported in the blood via _ to

Answer 24

via albumin to muscle, heart, liver

Question 25

the brain has no significant energy reserves which means...

Answer 25

relies on circulation with blood bringing glucose and oxygen

Question 26

brain uses 20% of total _ consumed by resting human (only 2% of body mass)

Answer 26

oxygen (O2)

Question 27

the brain switches to _ for energy needs (starvation) which are metabolized by _ to prevent _ breakdown for energy pruposes

Answer 27

switches to ketone bodies metabolized by TCA cycle and prevents protein breakdown

Question 28

cardiac muscle is exclusively _

Answer 28

aerobic

Question 29

_, _, _, and _ serve as fuel for the heart

Answer 29

glucose, lactate, FAs, and ketone bodies

Question 30

lack of O2 in heart leads to _

Answer 30

tissue death (MI)

Question 31

is skeletal muscle rich in glycogen?

Answer 31

yes; contains 75% of body's glycogen stores

Question 32

skeletal muscle uses _ for glycolysis

Answer 32

G6P for glycolysis as lacks glucose-6-phosphatase

Question 33

skeletal muscle, besides glycogen, uses _ and _ for energy

Answer 33

FAs and ketone bodies

Question 34

what fuel source immediately provides energy

Answer 34

phosphagen: regeneration of ATP by phosphocreatine via phosphocreatine kinase

Question 35

what fuel source provides short-term energy

Answer 35

anaerobic glycolysis and glycogenolysis; oxidation of free blood glucose into pyruvate or glycogen into glucose

Question 36

what fuel source provides long-term energy

Answer 36

oxidative system i.e. oxidative phosphorylation and FA metabolism

Question 37

phosphocreatine stored in _ to quickly regenerate ATP from ADP

Answer 37

muscle

Question 38

anaerobic glycolysis and glycogenolysis provides short-term energy and next forms lactate which causes decrease in _ which makes the shift into what?

Answer 38

glycogen->G6P->pyruvate->lactate; lactate causes decrease in power and muscle fatigue which causes the shift to a longer, more sustainable energy production system (OxPhos)

Question 39

what is the fate of lactate?

Answer 39

cori cyle which is the cooperation between muscle and liver; regenerates glucose from lactate (glycolysis forms pyruvate which forms lactate, lactate travels in the blood and is picked up by liver to undergo gluconeogenesis to form glucose which is transported back into the blood and is picked up by muscle)

Question 40

OxPhos provides energy via?

Answer 40

- involves ETC in mito to result in reduction of co-enzymes; forms NADH - oxidation of coenzymes NADH and FADH2 forms 3 and 2 ATP respectively - produces ATP via ATP synthase

Question 41

energy charge of a cell is defined as the ration of

Answer 41

ATP to ADP; ratio high in energy-rich cells and low in cells that are low in energy

Question 42

the reducing power of a cell is defined by

Answer 42

[NADH]:[NAD+]; represents the potential energy and varies inversely to [ATP]:[ADP] ratio

Question 43

when ATP levels are low, TCA cycle is _

Answer 43

up-regulated to produce more NADH as substrate for OxPhos

Question 44

when ATP levels are high, TCA cycle is _

Answer 44

down-regulated to limit the amount of NADH created and oxidized by the ETC

Question 45

cholecystokinin (CCK) is secreted by _ in response to _

Answer 45

secreted by SI in response to a meal; induce satiety signals as bind to receptors in brain and potentiate insulin action in the pancreas

Question 46

glucagon like peptide-1 (GLP1) is secreted by _ in response to _

Answer 46

secreted by cells in SI in response to fed state; tells pancreas to secrete more insulin

Question 47

short-term signals from GI tract relay feelings of _

Answer 47

satiety from gut to various regions of the brain

Question 48

CCK is a _ hormone secreted into the blood as a _ signal

Answer 48

is a peptide hormone secreted into the blood as a postprandial signal

Question 49

CCK binds to its receptor _ located in _

Answer 49

GPCR located in various peripheral neurons that relay signals to the brain

Question 50

ghrelin works as:

Answer 50

a peptide secreted by stomach to act on regions of hypothalamus to stimulate appetite

Question 51

leptin works as:

Answer 51

secreted in direct proportion to fat mass to act on receptor in hypothalamus to inhibit food intake and stimulate energy expenditure

Question 52

what are the 2 key signal molecules to regulate energy homeostasis over time (long-term)

Answer 52

1. leptin secreted by adipocytes reports on status of TAG stores 2. insulin secreted by beta cells of pancreas reports on status of blood glucose (carb availability)

Question 53

what happens in the liver during the fed state?

Answer 53

increase in: - glycolysis - glycogen synthesis - TG synthesis (TG goes into VLDLs as TAGs)

Question 54

what happens in the liver during the fasting state?

Answer 54

- glycogenolysis - gluconeogenesis - FA oxidation - ketone body formation

Question 55

what is the overall energy sensor in cells?

Answer 55

AMP-activated protein kinase (AMPK) is the cellular energy sensor

Question 56

when ATP is high, AMPK is _

Answer 56

inactive

Question 57

when ATP is low, AMPK is _

Answer 57

allosterically activated and phosphorylates many targets controlling cellular energy production and consumption

Question 58

AMPK is allosterically activated by _ which provides competition

Answer 58

competition between ATP and AMP