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Flashcards in Biochemistry Deck (293)
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181

Delayed wound healing, hypogonadism, decreased adult hair (axillary, facial, pubic), ansomia - vit deficiency?

Zinc deficiency

182

Vitamin K is necessary for the synthesis of what heme factors/proteins?

Clotting factors: 10, 9, 7, 2
Proteins C and S
*Warfarin = vit K antagonist

183

Fomepizole

inhibits alcohol dehydrogenase (ehtanol-->acetaldehyde); antidote for methanol or ethylene glycol poisoning

184

Disulfiram - "antibuse"

inhibits acetaldehyde dehydrogenase (acetaldehyde-->acetate); get acetaldehyde accumulation-->hang-over symptoms!

185

How may ethanol lead to hypoglycemia and acidosis?

ethanol metabolism increases the NADH/NAD ratio in the liver, causing: pyruvate-->lactate and Oxaloacetate-->malate
-this inhibits gluconeogenesis and stimulates fatty acid synthesis --> hypoglycemia and hepatic fatty change
-also: overproduction of lactate--> acidosis

186

Kwashiorkor vs Marasmus

Kwashiorkor- protein deficiency; edema (big belly), skin lesions, fatty liver (b/c decreased apolipoprotein synthesis)
Marasmus- malnutrition; muscle wasting, skinny, may have some edema

187

Actions of:
-kinases
-phosphorylase
-phosphatase
-dehydrogenase
-carboxylase

kinases- add a P, uses ATP
phosphorylases - add a P, does not use ATP
phosphotase - removes a P
dehydrogenase - oxidizes
carboxylase - transfers CO2 groups with help of biotin

188

rate limiting enzyme of glycolysis?

PFK-1

189

rate-limiter of gluconeogenesis?

F-1,6-BP

190

rate limiter of TCA cycle?

isocitrate dehydrogenase

191

rate-limiter of glycogen synthesis

glycogen synthase

192

rate-limiter of glycogenolysis

glycogen phosphorylase

193

rate-limiter of HMP shunt

G6PD

194

rate-limiter of de novo pyrimidine synthesis

CMP 2

195

rate-limiter of de novo purine synthesis

glutamine-PRPP amidotransferase

196

rate limiter of urea cycle

CMP 1

197

rate limiter of FA synthesis

ACC (acetyl-CoA carboxylase)

198

rate limiter of FA oxidation

Carnitine acyltransferase I

199

rate limiter of ketogenesis

HMG-CoA synthase

200

rate limiter of cholesterol synthesis

HMG-CoA reductase

201

rate-limiter of heme synthesis

aminolevulinate synthase

202

rate-limiter of bile acid synthesis

7-alpha-hydroxylase

203

Metabolic processes: Glycolysis, Gluconeogenesis, TCA cycle, acetyl-CoA production, HMP shunt, oxidative phosphorylation, Urea cycle, FA oxidation, FA synthesis, protein synthesis, steroid synthesis, heme synthesis:
-which take place in cytoplasm?
-which in mictochondria?
-which in both cytoplasm and mitochondria?

Cytoplasm: Glycolysis, FA synthesis, HMP shunt, protein synthesis (RER), steroid synthesis (SER)
Mitochondria: FA oxidation, acetyl-CoA production, TCA cycle, oxidative phosphorylation
Both: Heme synthesis, Urea cycle, Gluconeogenesis (HUG :))

204

Which 3 reactions in metabolism require TPP (thiamine cofactor)?

1) Transketolase (HMP shunt: ribulose-5-P --> fructose-6-P)
2) Pyruvate dehydrogenase (glycolysis/acetyl CoA prod: pyruvate--> acetyl CoA)
3) alpha-ketoglutarate dehydrogenase: alpha-ketoglutarate-->succinyl CoA

205

Which 3 metabolic reactions require a biotin cofactor?

1) ACC: acetyl-CoA-->malonyl CoA
2) pyruvate carboxylase: pyruvate-->oxaloacetate
3) propionyl CoA carboxylase: propionyl-CoA-->methylmalonyl CoA

206

which metabolic reaction requires vitamin B12 (cobalamin)?

methylmalonyl-CoA --> succinyl CoA

207

How many ATP are produced per glucose molecule (aerobic in heart/liver; aerobic in muscle; anaerobic)?

Aerobic metabolism via malate aspartate shuttle in heart and liver: 32 ATP/glucose
Aerobic via glycerol-3-phosphate shuttle in muscle: 30 ATP/glucose
Anaerobic: 2 ATP/glucose

208

What do these carriers carry:
-ATP
-NADH/NAD/FADH2
-Coenzyme A
-Lipoamide
-Biotin
-Tetrahydrofolates
-SAM
-TPP

-ATP --> phophoryl groups
-NADH/NAD/FADH2 --> electrons
-coenzyme A --> acyl groups
-lipoamide --> acyl groups
-biotin --> CO2
-tertrahydrofolates --> 1 Carbon units
-SAM --> CH3 groups
-TPP --> Aldehydes

209

NADPH:
-what process is it a product of?
-list 4 processes it is used in:

-NADPH = product of HMP shunt (why G6PD is so important!)
-NADPH is used in:
1) anabolic processes (ie steroid and FA synthesis)
2) respiratory burst (ie in phagolysosomes)
3) P-450
4) glutathione reductase (protects RBCs from oxidative damage by oxygen free radicals)

210

Hexonkinase vs Glucokinase:
-where is it located?
-affinity/km?
-capacity/vmax?
-induced by insulin?
-feedback inhibition on hexokinase/glucokinase?

*both can catalyze glucose --> G-6-P
*Hexokinase:
-ubiquitous
-high affinity/low km
-low capacity/low vmax
-uninduced by insulin

*Glucokinase:
-liver and Beta-cells of pancreas
-low affinity/high km
-high capacity/high vmax
-induced by insulin

*Feedback inhibition:
G-6-P---> inhibits hexokinase
F-6-P ---> inhibits glucokinase
ATP --> inhibits both (AMP stimulates both)
Citrate --> inhibits both