Exam 2 - Metabolism Flashcards
location of TCA
mitochondria
location of glycolysis
cytosol
ATP yield of one cycle of glycolysis
7 ATP (given NADH = 2.5 ATP)
regulation of glycolysis
product inhibition
allosteric control
covalent modulation
Fats can be converted to glucose. T/F?
F, it can only be converted as far as acetyl CoA due to irreversibility
Glycolysis and gluconeogenesis are both regulated at the same time. T/F?
F, both processes have different rate-limiting steps
Alanine is used as a substrate for glycolysis in the glucose-alanine cycle. T/F?
F, it is converted back to pyruvate for use in gluconeogenesis.
Glucose to pyruvate conversion requires a lot of energy. T/F?
T
hormone initiating glycolysis
insulin
hormone initiating gluconeogenesis
glucagon
Enzyme:
Fructose-6-P → Fructose-1,6-biP
PFK (phosphofructokinase)
Enzyme:
Fructose-1,6-bisphosphate → Fructose-6-Phosphate
fructose-1,6-biPase
Enzyme:
PEP → pyruvate
pyruvate kinase
absorption pathway of short- and medium-chain FAs
enter portal blood directly from enterocytes (readily absorbed)
bound to albumin
oxidized in the liver
absorption pathway of long-chain FAs
form chylomicrons and lipoproteins
drain into lymphatics via lacteals
enter bloodstream via thoracic duct into SCV
lipoproteins with the least and most proteins
most: HDL
least: chylomicron
lipoproteins with the least and most lipids
most: chylomicron
least: HDL
lipoproteins with the least and most fats
most: chylomicron
least: HDL
lipoproteins with the least and most free and esterified cholesterol
most: LDL
least: chylomicron
lipoproteins with the least and most phospholipids
most: HDL
least: chylomicron
LDL marker apoprotein
Apo B100
cofactor for LCAT
Apo A-I
cofactor for LPL
Apo C-II
enzyme inhibitors for LPL
Apo A-II and Apo C-III
ennzyme inhibitor for CETP
Apo C-I
ligands for LDL receptor
Apo B100 and Apo E
ligand for HDL receptor
Apo A-I
apoprotein with highest affinity to LDL receptor
Apo B100
enzyme catalyzing RLS in FA oxidation
acyl CoA synthetase
esterifies FA to CoA
net ATP produced from beta oxidation of 14-C saturated FA
formula: 14(n-1) + 10 - 2; where n = C/2
net ATP = 14(6) + 10 - 2 = 92 ATP
sources of acetyl CoA for FA synthesis
oxidative decarboxylation of pyruvate from glucose
oxidative degradation of some proteins
beta-oxidation of long-chain FA
sources of cholesterol
dietary - 0.4g/day
biliary/de novo - 2g/day
enzyme regulating cholesterol synthesis
HMG-CoA reductase
process involving HMG-CoA synthase and HMG-CoA lyase
ketogenesis
glucose hydrolysis intermediate converted to glycerol
DHAP
derivatives of cholesterol
corticosteroids
steroid hormones
bile salts and acids
Vit D
function of serum albumin
carrier protein for steroids, FAs, thyroid hormones
sources of N incorporated into urea during urea cycle
aspartate and ammonia
majority derived from glutamate
links urea cycle to TCA
fumarate
Why should essential AA be part of the diet?
The body cannot synthesize essential AA de novo and thus relies on external sources.
cofactor to forward homoCys –> Met
Vit B12
cofactor to forward homoCys –> Cys
Vit B6
possible condition following Vit B12 and B6 deficiency
homocystinuria
AA needing supplementation in diet of Px with phenylketonuria
tyrosine
impaired pathway in phenylketonuria
phenylalanine –> tyrosine
thus, tyrosine is deficient and needs supplementation in diet
principal action of thyroxine
increase O2 production increases metabolism (BMR)
factor directly related to BMR
lean body mass
importance of dietary proteins
provide essential amino acids for protein synthesis
suggested food to lower cholesterol
oat bran and other soluble fibers that reduce LDL levels
dietary fibers
decrease TAGs
increase stool bulk
improves chyme transmission
kwashiorkor
grossly underweight (<70% below normal) edema loss of pigmentation in hair and skin hypoalbuminemia moon facie and wet form
marasmus
extremely low weight
extreme wasting - loss of fat and muscle
dry form and geriatric face
cause of marasmus
calorie, protein, and nutrient deficiency
cause of kwashiorkor
protein deficiency despite adequate intake of calories
e.g. substituting milk for cassava
optimal proportion of carbs, fats, and proteins in diet
55~70% carbohydrates
20~30% fat
10~15% proteins
glycemic index
measure of blood glucose levels in response to food with respect to a standard food
glycemic load
glycemic index * carbohydrate concentration of food
food with relatively high glycemic index
bread > pasta and rice
biochemical measure of obesity/overnutrition
serum LDL
deficiencies resulting in anemia
folic acid
Vit B12
reaction associated with Vit C
hydroxylation - oxidizes the iron
oxidized Vit C is less/no longer effective
treatment for megaloblastic anemia from Vit B12 deficiency
folic acid
retinal
active form of Vit A
stored in liver
product of B-carotene hydrolysis
retinal
Vit D deficiency in children
rickets
Vit D deficiency in adults
osteomalacia
fat-soluble vitamins
Vit A, D, E, K
precursor of thiamine pyrophosphate
Vit B1
thiamine
Vit B1
riboflavin
Vit B2
Vit B6
pyridoxal, pyridoxine, pyridoxamine
thiamine deficiency
beri-beri
Wernicke-Korsakoff Syndrome
pellagra
can result from niacin deficiency
can lead to 3Ds - dermatitis, diarrhea, dementia
ascorbic acid
Vit A