Metabolism

Question 1

Where do FA synthesis, HMP shunt, steroid synthesis, and cholesterol synthesis occur?

Answer 1

Cytoplasm

Question 2

What cycles occur in both the mitochondria and cytoplasm?

Answer 2

Urea
GLuconeogenesis
Heme

Question 3

What is the rate limiting enzyme of glycolysis? Regulators?

Answer 3

Phosphofructokinase 1
+= F2,6-BP, AMP
- = CITRATE, ATP

Question 4

What is the rate limiting enzyme of Gluconeogenesis? regulators?

Answer 4

F-1,6-BPase
+ = ATP,
- = F2,6BP, AMP

Question 5

What is the rate limiting enzyme of TCA cycle? regulators?

Answer 5

Isocitrate dehydrogenase

- = NADH

Question 6

What is the rate limiting enzyme of HMP shunt?

Answer 6

G6PD

- = NADPH

Question 7

What is the rate limiting enzyme of de novo pyrimidine synthesis?

Answer 7

Carbamoyl phosphate synthetase II

Question 8

What is the rate limiting enzyme of de novo Purine synthesis?

Answer 8

Glutamine-PRPP amidotransferase

- = IMP, AMP, GMP

Question 9

What is the rate limiting enzyme of Urea cycle?

Answer 9

Carbamoyl phosphate synthetase I

+ = N- acetylglutamate

Question 10

What is the rate limiting enzyme of FA synthesis? regulators?

Answer 10

Acetyl-CoA carboxylase

- = Palmitoyl CoA, glucagon

Question 11

What is the rate limiting enzyme of FA oxidation?

Answer 11

Carnitine acytransferase I

- = Malonyl CoA

Question 12

What is the rate limiting enzyme of Ketogenesis?

Answer 12

HMG-CoA synthetase

Question 13

What is the rate limiting enzyme of cholesterol synthesis? regulators?

Answer 13

HMG CoA reductase

+ = Insulin, T3

Question 14

What enzyme is def in SEVERE galactosemia?

Answer 14

Galactose-1-phosphate uridyltransferase

Question 15

What enzyme is def in von Gierke’s disease?

Answer 15

Glucose-6-phosphatase= turns G6P–> Glucose for release during gluconeogenesis

Question 16

What enzyme is deficient in Fructose intolerance?

Answer 16

Aldolase B = Fructose-> G3P/ DHAP

Question 17

What enzymes require Thiamine as a cofactor?

Answer 17

Transketolase (ribulose 5P->F6P)
Pyruvate dh (pyruvate-> acetyl CoA)
aKetogluterate dh (aketo--> Succinyl-CoA)

Question 18

Difference btwn Hexokinase & Glucokinase?

Answer 18

Hexo= muscles/Fat, low Km, low Vmax, uninduced by insulin
Glucokinase= Liver/ Pancreatic beta cells, High Vmax/Km

Question 19

What molecules carry CO2, 1 carbon units, or methyl group?

Answer 19

CO2= Biotin
1carbon unit= THF
Methyl group= SAM

Question 20

What are the KETOGENIC AAs?

Answer 20

Lysine

Leucine

Question 21

benign asymptomatic enzyme def with Fructose appearing in urine?

Answer 21

Fructokinase def

Question 22

Enzyme def causing Hypoglycemia, Jaundice, cirrhosis, vomiting and build up of F-1-P?

Answer 22

Aldolase B def= Fructose intolerance

Question 23

Enzyme def causing Galactitol accumulation, galactose in urine and infantile cataracts?

Answer 23

Galactokinase Def

Question 24

Infant with failure to thrive, jaundice, Hepatomegaly, cataracts, and retardation, with Excess Galactitol accumulation?

Answer 24

Galactose 1-phosphate Uridyltransferase def

Question 25

Def in Galactosemia vs Fructose intolerance?

Answer 25

``` Fructose= Aldolase B Galactose= Uridyltransferase ```

Question 26

What cells have only Aldose reductase and NOT sorbitol dehydrogenase?

Answer 26

Retina Schwann Kidney

Question 27

What are the Ketogenic & glucogenic essential AAs?

Answer 27

``` Keto= Leu/ Lys Gluco= Met, Val, His ```

Question 28

What is the treatment for Hyperammonemia?

Answer 28

Low protein | Lactulose to Acidify GI and trap NH4

Question 29

What is Ornithine transcarbamyolase def?

Answer 29

MC Uraa cycle enzyme def= Hyperammonia + High Orotic acid in blood/urine **Infant with Tremor, somnolence, vomiting, and lactic acidosis.

Question 30

Production of DA/NE/ Epi require what 2 AAs?

Answer 30

Pheylalanine--> Tyrosine-> DA--> NE --> EPi

Question 31

Conversion of Dopa to DA requires? DA--> NE requires? NE--> Epi requires?

Answer 31

B6 Vit C SAM

Question 32

How is glycogenesis and muscle activity coordinated?

Answer 32

Ca/ Calmodulin in muscle activate Glycogen phosphorylase to breakdown glycogen

Question 33

Epi & glucagon have what similar actions?

Answer 33

increase cAMP activate PKA activate Glycogen phosphorylase

Question 34

Function of ApoE?

Answer 34

remnant uptake (all but LDL)

Question 35

Function of ApoA1?

Answer 35

Activate LCAT on HDL

Question 36

Function of ApoCII

Answer 36

Lipoprotein lipase cofactor (HDL, VLDL, chylomicrons)

Question 37

Function of ApoB48?

Answer 37

chylomicron secretion

Question 38

ApoB100?

Answer 38

Binds LDL receptor