Biochemistry - Heck Flashcards
absorptive state
after a meal - immediate
blood glucose level increases
insulin released
glycogen synthesis
protein synthesis
triglyceride synthesis
brain and RBCs - insensitive to insulin
post-absorptive state
during fast - 12 hours or overnight
glucagon released
glycogenolysis in liver
AA uptake for gluconeogenesis
epinephrine released
- muscle - AA to blood
- adipose - FA to blood
liver
maintain blood glucose
synthesize ketones from acetyl CoA
adipose
take up FA and convert to TGs for long term storage
resting skeletal muscle
release AA to blood
active skeletal muscle
fast twitch - anaerobic glycolysis from glycogen
slow twitch - oxidative metabolism of glycogen
-after several hours - switch to lipolysis
muscle contraction
activates the TCA cycle
via:
increase in Ca
increase in ADP
decreased NADH/NAD ration
high intensity level of exercise
increased lactate dehydrogenase
- convert pyruvate to lactate
- with anaerobic metabolism
NADH dehydrogenase
in ETC complex 1
increases with high intensity exercise
anaerobic muscle metabolism
high intensity exercise
need for ATP - exceeds mito capacity for ox phos
lactate production - increased NADH/NAD ratio directs pyruvate into lactate
H production - decreased pH, causing pain and fatigue
-lactic acid dissociates to lactate and H
aerobic muscle metabolism
low intensity exercise
rate of ATP utilization is lower
increased CO2 - complete oxidation of glucose to CO2
TCA cycle
generates NADH and FADH2
-driving force for ETC
NAD and FAD
from ETC
increase activity of TCA cycle
myosin ATPase
stimulates ADP
-increases activity of isocitrate DH (rate limiting of TCA cycle)
isocitrate DH
produces NADH - driving ETC
buildup of NADH
inhibit TCA cycle
-inhibit alpha-KG DH and isocitrate DH
muscle contraction
increase Ca
stimulates - isocitrate DH and alpha-KG DH - increased TCA cycle activity
citrate
with buildup - unable to proceed through TCA cycle
inhibits acetyl CoA entering TCA cycle
aerobic metabolism supplements
probably no immediate benefit
rate limiting factor - O2 availability, not cycle intermediates
CoQ, succinate, riboflavin, niacin, pantothenate
exercise
increases skeletal m capacity and efficiency for fuel ox
over time:
- more TCA cycle enzymes
- more ETC components
- more mitochondria - size and productivity
also more vasodilatory and lymphatic drainage
major metabolic source in anorexic
fuel for skeletal muscle - is fatty acids
ketone bodies
made in liver
-fuel for brain and skeletal m
elevated ammonia in blood
liver failure
elevated ketones in blood
during starvation
from FA produced by liver
severe hypoglycemia
passing out
unresponsive