Process: Fatty acid oxidation What is the rate-limiting enzyme?
Carnitine acyltransferase I
Rate-limiting enzyme: Carnitine acyltransferase I What is the process?
Fatty acid oxidation
Process: Ketogenesis What is the rate-limiting enzyme?
Pyruvate -< acetyl-CoA produces what?
1 NADH + 1 CO2
The TCA cycle (Krebs) produces what?
3 NADH, 1 FADH2, 2 CO2, 1 GTP per acetyl-CoA = 12 ATP/acetyl-CoA (2x
everything per glucose).
Where does the TCA cycle rxtn take place?
In the mitochondria.
Mnemonic to remeber the important molecules in the urea cycle
"O rdinarily, C areless C rappers A re A lso F rivolous A bout U rination" O
rnithine C arbamoyl phosphate C itrulline A spartate A rginosuccinate F umarate
A rginate U rea <img src="105d urea
Process: De novo pyrimidine synthesis What is the rate-limiting enzyme?
Aspartate transcarbamoylase (ATCase)
Rate-limiting enzyme: Aspartate transcarbamoylase (ATCase) What is the
De novo pyrimidine synthesis
Process: De novo purine synthesis Wha
Metabolic fuel use: Fasting and starvation (generally)
Priorities are to supply sufficient glucose to brain and RBCs and to preserve
Metabolic fuel use: fasting and starvation - days 1-3
Blood glucose is maintained by: 1.) Hepatic glycogenolysis
Energy malnutrition resulting in tissue and muscle wasting, loss of
subcutaneous fat, and variable edema. "M arasmus results in M uscle wasting"
Metabolism sites: Mitochondria
Fatty acid oxidation (beta-oxidation) Acetyl-CoA production TCA cycle
Maple syrup urine dz: etiology?
Blocked degradation of branched amino acids (I le, L eu, V aline) due to decr
alpha-ketoglutarate dehydrogenase. ("I L ove V ermont maple syrup from maple
trees with branches .")
Maple syrup urine dz: findings?
Process: TCA cycle What is the rate-limiting enzyme?
Rate-limiting enzyme: Isocitrate dehydrogenase What is the process?
Process: Glycogen synthesis What is the rate-limiting enzyme?
Pyruvate dehydrogenase deficiency: findings?
Pyruvate dehydrogenase deficiency: Tx?
Incr intake of ketogenic nutrients (e.g., high fat content or incr lysine and
leucine) *L ysine and L eucine are the only purely ketogenic amino acids.
Vitamin C (ascorbic acid): fxn?
Antioxidant. Also: 1.) Facilitates iron absorption by keeping iron in Fe2+ state
(more absorbable) 2.) Necessary for hydroxylation of proline and lysine in
collagen synthesis. 3.) Necessary for dopamine Beta-hydroxylase, wh
Mnemonic for the irreversible enzymes of gluconeogenesis?
"P athway P roduces F resh G lucose" P yruvate carboxylase P EP
carboxykinase F ructose-1,6-bisphosphatase G lucose-6-phosphatase
Where does gluconeogenesis occur (anatomically)?
Occurs primarily i
Type of lipoprotein: Chylomicron Function and route? Apolipoproteins?
Deligers dietary TGs to peripheral tissue. Delivers XOL to liver in the form of
chylomicron remnants, which are mostly depleted of their triaclyglycerols.
Secreted by intestinal epithel
Tx for PKU
Decr phenylalanine (contained in aspartame, e.g., NutraSweet) and incr tyrosine
Lack of proper dietary therapy during pregnancy. Findings in infant:
microcephaly, mental retardation, growth retardation, congenital heart de
Glycolytic enzyme deficiency: Associated with.? Why? Due to deficiencies
Associated w/ hemolytic anemia . Inability to maintain activity of Na+/K+
ATPase leads to RBC swelling and lysis. (RBCs metabolize glucse
anaerobically - no mitochondria - and t
Structure of ATP (what are the 3 important moieties?)
<img src="97a - ATP structure.JPG" />
Subtance: Phosphoryl What is the activated carrier for this substance?
Activated carriers: ATP What does substance does this carry?
Risk of what dz w/ albinism?
Lack of melanin results in an incr risk of skin cancer.
3 Forms of homocystinuria
1.) Cystathionine synthase deficiency (Tx: decr Met and Incr Cys, and incr B12
and folate in diet) 2.) Decr affinity of cystathionine synthase f
Lysosomal storage dz's (generally)
Each is caused by a deficiency in one of the many lysosomal enzymes. Results
in an accumulation of abnormal metabolic products. Include sphingolipidoses
and mucopolysaccharidoses. <img src="111c - Lysosomal storage dzs.J
Lipid transport enzymes: Cholesterol ester transfer protein (CETP)
Mediates transfer of XOL-esters to other lipoprotein particles. <img src="114b Lipid pathways.JPG" />
Major apolipoproteins: A-I
A -I A ctivates LCAT
Major apolipoproteins: B-100
B -100 B
Met, Val, Arg, His Ile, Phe, Thr, Trp Leu, Lys All essential AA's need to be
supplied in diet. (classified as glucogenic and/or ketogenic)
Ile, Phe, Thr, Trp Glucogenic AA's can be converted into glucose via
Subtance: 1-carbon units What is the activated carrier for this substance?
Activated carriers: Tetrahydrofolate What does substance does this carry?
Subtance: CH3 groups What is the activated carrier for this substance?
B12 (cobalamin): what rxtns does it help to proceed?
Homocysteine + N-methyl THF -(B12 + homocysteine methyl transferase)-<
Methionine + THF Methylmalonyl-CoA -(B12 + methylmalonyl-CoA
B12 (cobalamin): found where?
Found in animal p
What sphingolipidosis (lysosomal storage dz) does this describe? [don't look at
the picture if you want to guess] Findings: Peripheral neuropathy,
developmental delay, optic atrophy, globoid cells Def. enzyme:
Galactocerebrosidase Accum substrate: Galacto
NADPH: Product of.? Used in. (3 things)?
Product of the HMP shunt. Used in: 1.) Anabolic processes 2.) Respiratory burst
Hexokinase vs. glucokinase: why are the 2 enzymes similar?
Phosphorylation of glucose to yield glucose-6-phosphate serves as
Anabolic effects of inuslin (list of 6)
1.) Incr glucose transport ("In sulin moves glucose In to cells." 2.) Incr glycogen
synthesis and storage 3.) Incr TG synthesis and storage 4.) Incr Na+ retention
(kidneys) 5.) Incr protein synthesis (muscles) 6.) I