Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

Step 1 > Biochem > Flashcards

Biochem Flashcards

1
Q

What does glycerol kinase do?

A
  • in liver and kidney
  • degrades glycerol produced by degradation of triglycerides (in adipose tissue) to glycerol-3-P to synthesize glucose during gluconeogenesis
  • ex. may raise glucose in DKA
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

Tetrahydrobiopteran

A

BH4
Cofactor in synthesis of serotonin, tyrosine, and DOPA
Can lead to phenylketonuria due to inability to break down phenylalanine and tryptophan

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

Biotin

A

Acts as CO2 carrier on surface of the carboxylase enzyme. Necessary for conversion of pyruvate to oxaloacetate. Excessive ingestion of egg whites inhibits biotin.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

What protein is responsible for the intracellular effects of the G protein mediated adenylate cyclase second messenger system?

A

Protein Kinase A

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

Pyruvate Dehydrogenase, a ketogluterate dehydrogenase, and branched chain amino acid dehydrogenase require which five enzymes as cofactors?

(Tender Loving Care for Nancy)

A
  • Thiamine Pyrophosphate (from B1)
  • Lipoic Acid
  • CoA (from B5)
  • FAD (from B2)
  • NAD (from B3)
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

What amino acids can be broken down to form propionyl CoA?

A

Valine, Isoleucine, Threonine, and Methionine
Propionyl CoA breaks down to eventually become succinylcholine CoA and enter the TCA cycle. Build up of propionyl CoA due to deficiency of propionyl CoA carboxylase leads to prop ionic acidemia.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

a-ketoglutarate requires what vitamin as a cofactor to become succinyl CoA?

A
  • thiamine (B1)
  • deficient in alcoholics
  • rapid glucose admin to alcoholics depletes thiamine in CTA cycle and causes acute wernicke encephalopathy
  • thiamine also required for pyruvate dehydrogenase
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

Alkaptonuria

A
  • AR deficiency of homogentisic acid diozygenase
  • disorder of tyrosine metabolism
  • prevents conversion of tyrosine to fumarate
  • pathway backs up and inc. melanin, leading to black color of urine
  • ochronosis of ears, nose, etc
  • ochronotic arthropathy manifests in adulthood
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

Arsenic Poisoning

A
  • mechanism: binds sulfhydryl groups, disrupts cellular respiration and gluconeogenesis
  • sources: pesticides/insecticides, contaminated water, pressure treated wood
  • manifestations: garlic breath, vomiting, diarrhea, QT prolongation, hypo/hyperpigmentation, hyperkaratosis, stocking glove neuropathy
  • tx: dimercaprol, DMSA
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

Pyruvate Dehydrogenase Complex Deficiency

A
  • AR deficiency in the pyruvate dehydrogrogenase complex
  • neurologic sx usually start in infancy, ataxia
  • exacerbated in alcoholics due to thiamine deficiency
  • tx: inc. intake of high fat foods with ketogenic nutrients (ie. lysine and leucine)
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

Cysteinuria

A
  • AR
  • defective transport of cystine, ornithine, arginine, and lysine (dibasic amino acids) across intestinal and renal tubular epithelium
  • may cause nephrolithiasis with hexagonal cystine crystals due to high urinary concentration and inability to reabsorb cystine
  • tx: low methionine diet
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

Gauchers

A
  • AR
  • b-glucocerebrocidase deficiency
  • accumulated substrate: glucocerebroside
  • pancytopenia and hepatosplenomegaly
  • tissue paper macrophages
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

What does urease do?

A
  • splits urea into ammonia and CO2

- lowers acidity (inc. pH)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

Homocysteinuria

A

Presents with lens subluxation, marfanoid habitus, mental disability, and thromboembolic occlusion.
AR dec. in cystathione beta synthase, leading to inc. homocysteine.
Tx: pyridoxine (Bsix) which is a cofactor

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

Vitamin C is a required cofactor for what processes?

A
  • posttranslational modification of proline and lysine by prolyl hydroxylase and lysyl hydroxylase in the RER
  • defective hydroxylation dec. collagen and causes sx of scurvy such as corkscrew hairs, gum bleeding, etc.
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

Lesch Nyhan

A
  • Defective purine synthesis due to abesnt HGPRT (converts hypoxanthine to IMP and guanine to GMP)
  • causes inc. uric acid production
  • X linked recessive
  • mental retardation, self mutilation, gout,
  • tx: allopurinol, or febuxistat (2nd line)
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

Acute Intermittent Porphyria

A
  • AD
  • painful urination, dark urine, urinary incontinence
  • anxiety, delerium, agitation
  • autonomic nervous system dysfunction
  • proximal muscle weakness
  • inc. porphobilinogen in cytoplasm due to dec. porphobilinogen deaminase enzyme
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

Hunter

A
  • lysosomal storage dz
  • def. of iduronate sulfatase (leads to inc. heparin sulfate and dermatin sulfate)
  • X linked recessive
  • developmental delay, aggressive behavior, no corneal clouding
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

Galactosemia

A
  • absence of galactose-1-phosphate uridyltransferase
  • AR
  • accumulation of toxic substances (including galacitol in lens of eye)
  • failure to thrive, jaundice, hepatomegaly, infantile cataracts, mental retardation
  • can lead to e. coli sepsis in neonates
  • tx: exclude galactose and lactose from diet
20
Q

Fructose Intolerance

A
  • hereditary deficiency of aldolase B
  • AR
  • fructose-1-P accumulates
  • symptoms present following eating fruit, honey, juice
  • urine dipstick neg (tests glucose only)
  • hypoglycemia, jaundice, cirrhosis, vomiting
  • dec. intake of fructose and sucrose
21
Q

Reducing Sugar Urine Test

A

-nonspecific test for inborn errors of carbohydrate metabolism

22
Q

Trick for remembering enzymes deficient in fructose intolerance and classic galactosemia.

A
  • FAB GUT

- Fructose is to Aldolase B as Galactose is to Uridyl Transferase

23
Q

Familial Chylomicronemia Syndrome (type 1)

A
  • AR
  • protein defect: lipoprotein lipase, apoC-2
  • elevated lipoprotein: chylomicron, TG, cholesterol
  • sx: acute pancreatitis, lipemia retinalis, eruptive xanthomas, creamy layer supernatent, hepatosplenomegaly
24
Q

Familial Hypercholesterolemia (type 2a)

A
  • AD
  • protein defect: LDL receptor, apoB100
  • elevated lipoprotein: LDL, cholesterol
  • sx: premature atherosclerosis, tendon xanthomas, xanthelasmas, MI at young age
25
Q

Familial Dysbetalipoproteinemia (type 3)

A
  • protein defect: ApoE 3 and 4
  • elevated lipoproteins: chylomicron and VLDL remnants (IDL)
  • sx: premature atherosclerosis, tuberuptive and palmar xanthomas
26
Q

Familial Hypertriglyceridemia (type 4)

A
  • AD
  • protein defect: polygenic
  • elevated lipoproteins: VLDL, TG
  • hepatic overproduction of VLDL
  • sx: coronary dz, pancreatitis (hyperTG), and diabetes, lipemia retinalis, eruptive xanthomas
27
Q

Xanthelasmas

A

-cholesterol deposits usually seen on eyelids

28
Q

Erupting Xanthomas

A
  • subcutaneous depsosits
  • commonly seen on tendons
  • due to excessive lipids engulfed by macrophages (foam cells)
29
Q

Things that cause left shift of hemoglobin dissociation curve:

A
  • left shift = inc. O2 affinity
  • inc. pH
  • dec. temp
  • dec. 2, 3-diphosphoglycerate
  • right shift is opposite
30
Q

2, 3, BPG

A
  • high levels cause R shift in heme curve

- fetal hemoglobin has dec. affinity for 2, 3, BPG causing O2 to shift from mother to fetus

31
Q

What vitamin is a cofactor in transamination reactions?

A

-vitamin B6 pyridoxine

32
Q

What amino acid is broken down to serotonin?

A

-tryptophan

33
Q

What amino acids are broken down to catecholamines?

A
  • phenylalanine

- tyrosine

34
Q

Steps to Insulin Release

A
  • glucose enters pancreatic beta cell through glut 2
  • glucose is made into ATP
  • ATP closes K channel, leading to depolarization of cell membrane
  • allows opening of Ca channel
  • signals exocytosis of insulin out of cell
  • GLP1 receptor also contributes to inc. insulin
35
Q

Cause of Maternal Onset Diabetes

A

-dec. function of glucokinase

36
Q

Most abundant amino acid in collagen?

A

-Glycine

37
Q

What do nitrites do to hemoglobin?

A
  • shift Fe2+ to Fe3+ (methemglobinemia)

- Fe3+ binds tightly to cyanide, causes dusky discoloration of skin, and cannot carry oxygen

38
Q

What are signaling molecules have intracellular receptors?

A
  • cortisol
  • cholesterol derived hormones
  • TSH
39
Q

Ornithine and Citrulline are part of what pathway?

A

-urea cycle of protein degradation

40
Q

Hormone Sensitive Lipase

A
  • enzyme in adipose tissue that catalyzes stored triglycerides into free fatty acids and glycerol
  • in starvation, provides substrates for gluconeogenesis and ketone formation
41
Q

tRNA

A
  • acceptor stem: 3’ end has CCA tail that amino acid binds to
  • D loop: facilitates correct tRNA recognition by aminoacul tRNA synthetase
  • anticodon loop: is complementary to mRNA sequence
  • T loop: necessary for binding of ribosomes
42
Q

Fabry

A
  • X linked recessive
  • deficiency: a-galactosidase
  • accumulated substrate: globotriaosylceramide
  • sx: angiokeratomas, peripheral neuropathy, glomerulopathy
43
Q

Tay Sachs

A
  • AR
  • deficiency: B hexosaminidase
  • accumulated substrate: GM2 ganglioside
  • sx: macular cherry red spot, progressive neurodegeneration
44
Q

Neimann Pick

A
  • AR
  • deficiency: sphingomyelinase
  • accumulated substrate: sphingomyelin
  • sx: macular cherry red spot, progressive neurodegeneration, hepatosplenomegaly (not seen in tay sachs)
45
Q

Krabbe

A
  • AR
  • deficiency: galactocerebrosidase
  • accumulated substrate: galactocerebroside and psychosine
  • sx: progressive neurodegeneration, periphary neuropathy, optic atrophy
46
Q

Metachromatic Leukodystrophy

A
  • AR
  • deficiency: arylsulfatase A
  • accumulated substrate: cerebroside sulfate
  • sx: progressive neurodegeneration, peripheral neuropathy
47
Q

Hurler

A
  • enlarged skull and abnormally shaped ribs and vertebrae
  • corneal clouding
  • accumulation of heparan sulfate and dermatan sulfate due to a-L-iduronidase deficiency

Step 1 (23 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions