Biochemistry- Metabolism Flashcards by Robin Sautter

What metabolic functions occur in the mitochondria?

fatty acid oxidation (beta-oxidation)
acetyl-CoA production
TCA cycle
oxidative phosphorylation

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What metabolic functions occur in the cytoplasm?

glycolysis
fatty acid synthesis
cholesterol synthesis
steroid synthesis (SER)
protein synthesis (RER)
HMP shunt

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What metabolic functions occur in both the cytoplasm and mitochondria?

Heme synthesis
Gluconeogenesis
Urea cycle

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What is the function of a kinase?

Uses ATP to add a phosphate group onto a substrate

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What is the function of a phosphorylase?

Adds a phosphate group onto a substrate WITHOUT using ATP

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What is the function of a phosphatase?

Removes a phosphate group

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What is the function of a dehydrogenase?

catalyzes oxidation-reduction reactions

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What is the function of a hydroxylase?

adds a hydroxyl group onto a substrate

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What is the function of a carboxylase?

transfers CO2 groups with the help of biotin

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What is the function of a mutate?

relocates a functional group within a molecule

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How many ATP does aerobic glycolysis produce?

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How many ATP does anaerobic glycolysis produce?

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How many ATP does arsenic cause glycolysis to produce?

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What type of processes is NAD+ generally used in?

catabolic processes

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What type of processes is NADPH generally used in?

anabolic processes (steroid and fatty acid synthesis)

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NADPH is also used in what other functions of the cell?

anabolic processes
respiratory burst
cytochrome P-450 system
glutathione reductase

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Where is hexokinase located and what are some characteristics about the enzyme?

Most tissues

higher affinity (lower Km)
higher capacity (lower Vmax)
NOT induced by insulin
Feedback-inhibited by glucose-6-phosphate
NO gene mutation assoc. w/ maturity-onset diabetes of the young (MODY)

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Where is glucokinase located and what are some characteristics about the enzyme?

Liver, beta-cells of pancreas

lower affinity (higher Km)
lower capacity (higher Vmax)
Induced by insulin
Feedback is NOT induced by glucose-6-phosphate
Gene mutation associated with maturity-onset of diabetes of the young (MODY)

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How many ATP are produced through glycolysis?

2 ATP

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FBPase-2 an PFK-2 are the same bifunctional enzyme who function is reversed by phosphorylation by what protein?

protein kinase A

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What is the order of substrates in the TCA cycle?

Citrate
Isocitrate
alpha-ketoglutarate
Succinyl-Coa
Succinate
Fumarate
Malate
Oxaloacetate

Citrate Is Kreb’s Starting Substrate For Making Oxaloacetate!

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What are some electron transport inhibitors?

Rotenone (Complex I)
Cyanide (Complex IV)
Antimycin A (Complex III)
CO (Complex IV)

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What is an ATP synthase inhibitor?

Oligomycin

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What are some uncoupling agents?

2,4- dinitrophenol
aspirin
thermogenin in brown fat

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What are the enzymes necessary for gluconeogenesis?

Pyruvate carboxylase Phosphoenolpyruvate carboxykinase Fructose-1,6-biphosphatase Glucose-6-phosphatase Pathway Produces Fresh Glucose

What organ does gluconeogenesis primarily occur in?

liver

What does propionyl-CoA form from?

odd chain fatty acids

Where in the TCA cycle can propionyl-CoA enter?

Succinyl-CoA

What are major products of the HMP shunt and what are these products used for in the body?

NADPH --> glutathione reduction inside RBCs, FA and cholesterol biosynthesis Ribose --> nucleotide synthesis and glycolytic intermediates

Where does the HMP shunt occur?

lactating mammary glands liver adrenal cortex (sites for FA or steroid synthesis) RBCs

What is the purpose of the respiratory burst (oxidative burst)?

Plays an important role in the immune response (both creation and neutralization with ROS)

What type of infections are patients with chronic granulomatous disease at an increase risk for and why?

Catalase + microorganisms because these organisms can neutralize their own H2O2

What is the most common human enzyme deficiency?

Glucose-6-phosphate dehydrogenase deficiency

What population is G6PD def. more common in?

African Americans

What can precipitate hemolytic anemia in individuals with G6PD deficiency?

``` fava beans sulfonamides primaquine anti-TB drugs infections ```

What type of inheritance is G6PD deficiency?

X-linked Recessive

What symptoms are seen with essential fructosuria? Is it a serious condition?

Fructose in the blood and urine Benign condition

What inheritance pattern is seen in both essential fructosuria and fructose intolerance?

Autosomal recessive

What is the sequelae of fructose intolerance?

fructose-1-phosphate accumulates --> decrease in available phosphate --> inhibition of glycogenolysis and gluconeogenesis

What are symptoms of fructose intolerance?

hypoglycemia jaundice cirrhosis vomiting

What is the treatment for fructose intolerance?

decrease intake of both fructose and sucrose

What substrate accumulates in galactokinase deficiency?

galactitol

What are symptoms of galactokinase deficiency?

galactose in blood and urine infantile cataracts may present as failure to track objects or to develop a social smile

What enzyme is deficient in classic galactosemia?

galactose-1-phosphate uridyltransferase

What are symptoms of classic galactosemia?

``` failure to thrive jaundice hepatomegaly infantile cataracts intellectual disability ```

What is the treatment for classic galactosemia?

exclude galactose and lactose (galactose + glucose) from the diet

What is the pathogenesis of diabetes symptoms due to sorbitol metabolism?

chronic hyperglycemia --> increase glucose converted to sortbitol --> increase sorbitol accumulation --> osmotic damage --> peripheral neuropathy, cataracts, and retinopathy

What are findings associated with lactase deficiency?

bloating, cramps, flatulence, and osmotic diarrhea

What is the treatment for lactase deficiency?

avoid dairy products | add lactase pills

What are the essential amino acids?

``` Phe Val Thr Trp Ile Met His Arg Leu Lys ``` PVT TIM HALL

What are the acidic amino acids?

Asp. and Glu

What are the basic amino acids?

Arg., Lys, and His

Which amino acids are increased in histones?

Arg and Lys

What is the function of the urea cycle?

Excess nitrogen (NH3) generated by amino acid metabolism is converted to urea to be excreted by the kidneys

What is the pneumonic to remember the order for the urea cycle?

Ordinarily, Careless Crappers Are Also Frivolous About Urination

What are causes of hyperammonemia?

acquired (liver disease) | hereditary (urea cycle enzyme deficiencies)

What condition is caused by N-acetylglutamate deficiency?

hyperammonemia

What finding would indicate an N-acetylglutamate deficiency vs. a carbamoyl phosphate synthase I deficiency?

increased ornithine with normal urea cycle enzymes suggests hereditary N-acetylglutamate deficiency

What is the amino acid derivative of NE and epi?

phenylalanine

What is the amino acid derivative of NAD+/NADP+?

tryptophan

What is the amino acid derivative of melatonin?

tryptophan

What is the amino acid derivative of histamine?

histidine

What is the amino acid derivative of heme?

glycine

What is the amino acid derivative of GABA and glutathione?

glutamate

What is the amino acid derivative of creatine, urea, and NO?

arginine

What disease is caused by a deficiency in phenylalanine hydroxyls?

PKU

What disease is caused by a deficiency in tyrosinase?

albinism

What disease is caused by a deficiency in homogentisate oxidase?

alkaptouria

What is the treatment for homocystinuria due to cystathione synthase deficiency?

decrease methionine increase cysteine increase B12 and folate in diet

What is the treatment for homocystinuria due to a decreased affinity of cystathione synthase for B6?

REALLY increase B6 in diet | increase cysteine in diet

What is the treatment for homocystinuria due to homocysteine methyltransferase deficiency?

increase methionine in diet

What are the findings for homocystinuria?

``` REALLY increased homocysteine in urine intellectual disability osteoporosis atherosclerosis tall stature kyphosis lens subluxation (down and inward) thrombosis ```

What is the cause of cystinuria?

defect in transport in PCT in kidney and intestinal cells

What amino acids or substrates does the defected transporter in cystinuria usually transport?

COLA Cysteine Ornithine Lysine Arginine

What test is diagnostic for cystinuria?

urinary cyanide-nitroprusside test

What mode of inheritance is cystinuria?

What is the enzyme deficiency in Maple Syrup Urine Disease?

decrease in alpha-ketoacid dehydrogenase (B1)

What amino acids accumulate in Maple Syrup Urine Disease?

isoleucine leucine valine

What is the mode of inheritance for Maple Syrup Urine Disease?

What are the physical findings in Maple Syrup Urine Disease?

severe intellectual disability severe CNS defects urine smells like maple syrup/burnt sugar death

What is the treatment for Maple Syrup Urine Disease?

restrict leucine, isoleucine, and valine in diet | thiamine supplementation

What enzyme cleaves glucose - 1- phosphate residues off branched glycogen?

glycogen phosphorylase

What is the enzyme deficient in Von Gierke Disease (type I)?

glucose-6-phosphate

What is the treatment for Von Gierke Disease?

frequent oral glucose/cornstarch | avoidance of fructose and galactose

What is the enzyme deficient in Pompe Disease (type II)?

lysosomal alpha - 1, 4- glucosidase (acid maltase)

What are the findings in Pompe Disease?

cardiomyopathy and systemic findings leading to early death | hypotonia

What is the enzyme deficient in Cori Disease (type III)?

debranching enzyme (alpha-1,6-glucosidase)

What are the findings in Cori Disease?

milder form of type I (Von Gierke Disease) with NORMAL blood lactate levels

What is the enzyme deficiency in McArdle disease (type V)?

skeletal muscle glycogen phosphorylase

What are the findings in McArdle disease?

increased glycogen in muscle but cannot break it down --> MUSCLE CRAMPS, MYOGLOBINURIA, and ARRHYTHMIA (d/t electrolyte imbalances)

Biochemistry- Metabolism Flashcards

(90 cards)