Exam 3 Integration of Metabolism Flashcards
aas are _ into acetyl coA
deaminated
carbohydrates are digested into monosaccharides where they enter _ to make acetyl coA
glycolysis
FAs undergo _ into acetyl coA
B-oxidation
we can have glycogen metabolism via the key molecule _
G6P
formation of pyruvate from _ via _
from G6P via glycolysis or gluconeogenesis
formation of ribose-5-phosphate from _ via _
from G6P via PP pathway
formation of acetyl coA from _ via _
pyruvate via pyruvate dehydrogenase
formation of lactate from _ via _
from pyruvate via lactate dehydrogenase (exercising muscle)
formation of alanine from _ via _
pyruvate via transaminase
formation of OAA from _ via _
pyruvate via TCA cycle
formation of CO2 from _ via _
acetyl coA via TCA cycle
formation of ketone bodies from _
from excess acetyl coA (ketone body metabolism)
formation of FAs from _
acetyl coA (building block)
preferred energy source of RBCs?
glucose because has no other organelles
preferred energy source of brain?
glucose and ketone bodies under conditions of starvation
preferred energy source of adipose tissue?
glucose and FAs
preferred energy source of liver?
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)
preferred energy source of muscles?
glucose, FAs, aas
why is the liver the “MVP” of metabolism?
- 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
aas go directly to the liver through _ after absorption
portal vein
liver uses aas to make:
proteins, biosynthesis of nitrogen-containing molecules, for gluconeogenesis, or for feul
adipose tissue synthesizes and stores _ as signaled by _
synthesizes and stores TAGs as signaled by insulin (fed state)
adipose tissue releases _ + _ as signaled by _
releases FAs + glycerol as signaled by glucagon/epinephrine (hunger, exercise)
FAs are transported in the blood via _ to
via albumin to muscle, heart, liver
the brain has no significant energy reserves which means…
relies on circulation with blood bringing glucose and oxygen
brain uses 20% of total _ consumed by resting human (only 2% of body mass)
oxygen (O2)
the brain switches to _ for energy needs (starvation) which are metabolized by _ to prevent _ breakdown for energy pruposes
switches to ketone bodies metabolized by TCA cycle and prevents protein breakdown
cardiac muscle is exclusively _
aerobic
_, _, _, and _ serve as fuel for the heart
glucose, lactate, FAs, and ketone bodies
lack of O2 in heart leads to _
tissue death (MI)
is skeletal muscle rich in glycogen?
yes; contains 75% of body’s glycogen stores
skeletal muscle uses _ for glycolysis
G6P for glycolysis as lacks glucose-6-phosphatase
skeletal muscle, besides glycogen, uses _ and _ for energy
FAs and ketone bodies
what fuel source immediately provides energy
phosphagen: regeneration of ATP by phosphocreatine via phosphocreatine kinase
what fuel source provides short-term energy
anaerobic glycolysis and glycogenolysis; oxidation of free blood glucose into pyruvate or glycogen into glucose
what fuel source provides long-term energy
oxidative system i.e. oxidative phosphorylation and FA metabolism
phosphocreatine stored in _ to quickly regenerate ATP from ADP
muscle
anaerobic glycolysis and glycogenolysis provides short-term energy and next forms lactate which causes decrease in _ which makes the shift into what?
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)
what is the fate of lactate?
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)
OxPhos provides energy via?
- 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
energy charge of a cell is defined as the ration of
ATP to ADP; ratio high in energy-rich cells and low in cells that are low in energy
the reducing power of a cell is defined by
when ATP levels are low, TCA cycle is _
up-regulated to produce more NADH as substrate for OxPhos
when ATP levels are high, TCA cycle is _
down-regulated to limit the amount of NADH created and oxidized by the ETC
cholecystokinin (CCK) is secreted by _ in response to _
secreted by SI in response to a meal; induce satiety signals as bind to receptors in brain and potentiate insulin action in the pancreas
glucagon like peptide-1 (GLP1) is secreted by _ in response to _
secreted by cells in SI in response to fed state; tells pancreas to secrete more insulin
short-term signals from GI tract relay feelings of _
satiety from gut to various regions of the brain
CCK is a _ hormone secreted into the blood as a _ signal
is a peptide hormone secreted into the blood as a postprandial signal
CCK binds to its receptor _ located in _
GPCR located in various peripheral neurons that relay signals to the brain
ghrelin works as:
a peptide secreted by stomach to act on regions of hypothalamus to stimulate appetite
leptin works as:
secreted in direct proportion to fat mass to act on receptor in hypothalamus to inhibit food intake and stimulate energy expenditure
what are the 2 key signal molecules to regulate energy homeostasis over time (long-term)
- leptin secreted by adipocytes reports on status of TAG stores
- insulin secreted by beta cells of pancreas reports on status of blood glucose (carb availability)
what happens in the liver during the fed state?
increase in:
- glycolysis
- glycogen synthesis
- TG synthesis (TG goes into VLDLs as TAGs)
what happens in the liver during the fasting state?
- glycogenolysis
- gluconeogenesis
- FA oxidation
- ketone body formation
what is the overall energy sensor in cells?
AMP-activated protein kinase (AMPK) is the cellular energy sensor
when ATP is high, AMPK is _
inactive
when ATP is low, AMPK is _
allosterically activated and phosphorylates many targets controlling cellular energy production and consumption
AMPK is allosterically activated by _ which provides competition
competition between ATP and AMP
