Brainscape's Knowledge GenomeTM

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


See full index

UWorld Question Review > Biochemistry UWorld > Flashcards

Biochemistry UWorld Flashcards

1
Q

Anticitrullinated peptides antibody highly specific for?

A

Rheumatoid arthritis

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

Anti DS DNA highly specific for…

A

SLE

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

Anti centromere antibodies highly specific for?

A

Crest syndrome

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

Polycistronic

A

1 mRNA codes for many proteins. One promoter. Common in prokaryotes, very rare in eukaryotes.

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

Indirect bilirubin uptake vs direct bilirubin output?

A

Unconjugated bilirubin uptake into hepatocytes is a passive process. Conjugated bilirubin is actively pumped out using MDR or OAT

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

Scurvy symptoms

A

Hemorrhagse, subperiosteal hematomas, bleeding, gingival swelling

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

Cofactor needed for ALA synthesis

A

B6 (pyridoxal phosphate)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

Acute intermittent porphyria

A

Disease marked by painful abdomen, port-wine colored urine, polyneuropathy, psychological disturbances (anxiety), precipitated by drugs (phenobarbital, griseofulvin, phenytoin).

Caused by a defect in porphobilinogen deaminase which causes phorphobilinogen to build up, as well as ALA and coproporphyrinogen.

Treat with heme and glucose to inhibit ala synthase.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

First step of heme synthesis

A

Glycine and succinyl coa form ALA with alas and b6

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

Elastin components, differences with collagen

A

Made of Glycine, alanine, valine, proline and lysine too.

Not as many residues are hydroxylated.

Extensive cross linkingis responsible for elastin being able to snap back into place.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

Porphyria cutanea tardea

A

Late defect in heme synthesis which causes photosensitivity and tea colored urine. This is the most common porphyria.

Due to a deficiency in uroporphyrinogen decarbodylase, which causes uroporphyrinogen III to build up. No coproporphyrinogen made.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

What type of receptor is the insulin receptor

A

Receptor tyrosine kinase.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

How does TNA induce insulin resistance?

A

Activates serine kinases, which phosphorylate IRS-1 serine residues, this prevents tyrosine phosphorylation on IRS 1 by insulin.

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

Methylmalonyl CoA becomes?

A

Succinyl CoA via a mutase reaction with B12

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

Homocysteine becomes?

A

Methionine via homocysteine methyl transferase (uses THF/folate.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

How are triglycerides used for energy?

A

They are used in glycolysis because glycerol can become Glyceraldehyde 3 P.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

Amanitin does what…

A

Blocks RNA polymerase II.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

Energy usage in states of fasting

12-18 hours?
18 hours +
1 week +

A

12- 18 hours. Glycogen is used
longer than 18 hours, gluconeogenesis is used
prolonged starvation, fatty acids are used.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

Where is the receptor for thyroid hormone?

For TSH?

A

In the nucleus

TSH transmembrane

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

How are valine and isoleucine broken down?

A

Via alphaketoacid dehydrogenase (using the 5 cofactors used by PDH).

Become propionyl coA, then methyl malonyl coa (in a carboxylase reaction that requires biotin), then succinyl coa (in a mutase reaction that requires B12).

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

How is leucine broken down?

A

Becomes acetyl-coa, which is shunted into TCA.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

Can RBCs use ketones?

A

No, because they lack mitochondria

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
23
Q

How is sorbitol created and used

A

Glucose becomes sorbitol via aldose reductase and NADPH. Sorbitol then becomes fructose via sorbitol dehydrogenase (and NAD).

Schwann cells, retina, and kidneys have only aldose reductase. Lens has primarily aldose reductase.

Sorbitol is osmotically active.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
24
Q

Draw out galactose metabolism

A

Look at first aid

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
25
Q

Classic galactosemia

A

Deficiency of galactose uridyltransferase. Causes vomiting, lethargy, failure to thrive, when breastfeeding begins. Can also cause cataracts. Can lead to E.Coli sepsis in neonates****

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
26
Q

Tumor lysis syndrome

A

Large numbers of cells destroyed quickly due to chemotherapy. Causes rapid increase in potassium, phosphate, nucleic acids in blood. Decrease risk with aggressive hydration.

Decrease uric acid with allopurinol or rasburicase (which is urate oxidase) creates allantoin from uric acid to treat renal sxs of tumor lysis

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
27
Q

Rasburicase

A

Urate oxidase creates allantoin from uric acid to decrease renal symptoms of tumor lysis syndrome

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
28
Q

Probenecid

A

Uricosuric agent that decreases uric acid secretion. Only can be used in patient has good renal function, not in the case of uric acid nephropathy from tumor lysis syndrome

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
29
Q

Kozak sequence

A

Upstream from AUG, key factor in translation initiation in eukaryotes.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
30
Q

Hexokinase

A

Takes G to G6P.

Also takes fructose from diet and turns it into F6P for use in glycolysis.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
31
Q

Purpose of lactate?

A

To generate NAD from pyruvate if there is no O2 to regenerate NAD in the electron transport chain.

NAD regeneration is necessary so glycolysis can continue.

32
Q

Alkaptonuria

A

Darkening of tissues and turine due to a defect in homogentisate oxidase. Homogentisate cannot become maletoacetic acid

33
Q

Where is rRNA synthesized?

A

In the nucleolus

34
Q

How is insulin released

A

Glukokinase traps glucose and greates ATP in pancreatic beta cells. ATP closes K channels, cell depolarizes, ca comes in, insulin released.

35
Q

Glucokinase deficiency

A

Maturity onset diabetes, causes a decrease in glucose trapped in cells, more in bloodstream

36
Q

Which sugar is fed into glycolysis AFTER the rate determining enzyme PFK?

A

Fructose. Is turned into fructose 1 phosphate by fructokinase, then into glyceraldehyde and DHAP via aldolase B, Glyceraldehyde is then turned into G3P by triose kinase.

37
Q

Function of JAK?

A

Kinase that activates STAT. Mutated in myelofibroses, essential thrombocytosis, and polycythemia vera.

38
Q

Arginase deficiency

A

Arginine cannot become urea and OAA. ammonia builds up in the blood causing symtpoms like asterixis, somnolence, vomiting, cerebral edema.

39
Q

Which enzymes use B1

A

Transketolase (used in reversible reactions of HMP shunt to create r5P g3p f6p), akg dehydrogenase, pyruvate dehydrogenase

40
Q

What is transketolase used for?

A

To create r5p, g3p and f6p from ribulose 5 phosphate. Needs B1!

41
Q

Thiamine necessary for?

A

Glucose utilization –> cannot give alcoholics glucose without B1.

42
Q

Which reactions use BH4?

A

Phenylalanine hydroxylase, tyrosine hydroxylase, serotonin synthesis, and NO synthesis.

BH4 reductase can cause PKU

43
Q

Where are cortisol receptors located? Steps of cort activation during fasting

A

In cytoplasm bound to heat shock protein. When cort binds the receptors dimerize and translocate to the nucleus to initiate gluconeogenesis

44
Q

Alanine Transaminase reaction, where does the NH3 group go?

A

Goes to alphaketoglutarate to form glutamate

45
Q

Which steps of heme synthesis does lead inhibit?

A

ALAD and ferrochelatase

46
Q

Regulator of pyruvate carboxylase in gluconeogenesis

A

Pyruvate becomes OAA via pyruvate carboxylase, which is activated by ACETYL COA

47
Q

How to create cyanide poisoning

A

Use nitrites to create methemoglobin,

48
Q

Symptoms of homocystinuria

A

Marfanoid habitus, bilateral lens subluxation, hypercoagulability.

Can be caused by no B12 (can’t become met), or no B6 (because B6 and serine are needed for cystathionine synthase)

49
Q

Inheritance of familial hypercholesterolemia

A

Autosomal dominant

50
Q

Function of beta-galactosidase

A

Turns lactose into galactose

51
Q

Gibbs free energy negative?

Postive?

A

If negative, products are favored.

If positive, reactants are favored

52
Q

How to synthesize niacin

A

Tryptophan with B6 and B2

53
Q

Measles can be treated with

A

Vitamin A

54
Q

What two types of reactions require pyridoxal phosphate?

A

Transamination and decarboxylation.

55
Q

Hartnup disease

A

Loss of tryptophan in urine so niacin and 5HT can’t be made. Tryptophan in urine

56
Q

How does acyclovir work?

A

Guanosine nucleotide that stops viral chain elongation. Must be phosphorylated in viral cells.

57
Q

Hox proteins do what?

A

DNA binding proteins

58
Q

Energy usage at 1 week of starvation

A

FFAs are used to generate acetyl coa

59
Q

Which cells cannot use ketone bodies for energy?

A

Red blood cells and liver cells.

60
Q

Symptoms of PKU

A

Intellectual disability, seizures, fair skin, eczema

61
Q

Do prokaryotes have introns?

A

Rarely. Also have only 1 origin of replication, where eukaryotes have multiple.

62
Q

Which enzymes require biotin?

A

Acetyl CoA carboxylase (which takes acetyl CoA to malonyl CoA during fatty acid synthesis)

Pyruvate carboxylase (which takes pyruvate to OAA in gluconeogenesis)

Propionyl carboxylase (which takes amino acids (valine) into propionyl coa to methylmalonyl coa)

63
Q

Pseudotumor cerebri symptoms

A

Headaches, papilledema, vomiting

64
Q

Which enzymes require B1,B2,B3,B5, lipoate?

A

Alpha ketoglutarate dehydrogenase
Pyruvate dehydrogenase
Alphaketoacid dehydrogenase (turns long chain FA into propionate and breaks down valine/isoleucine)

65
Q

D arm purpose?

T arm purpose

A

AA charging (mediates correct recognition by correct aminoacyl trna synthetase)

T arm for tRNA/ribosome binding

66
Q

PEPCK cofactors

A

To turn OAA to PEP, must have GTP, which is made when succinyl CoA becomes succinate

67
Q

Where are very long chain fatty acids metabolized?

A

In peroxisomes. No peroxisomes = zellweger’s disease. Fatty acids accumulate, no myelin formation, hypotonia and seizures, hepatomegaly

68
Q

GLUT 4

A

Responsible for INSULIN MEDIATED UPTAKE in skeletal muscles and adipocytes. Other gluts are insulin indepenent.

69
Q

Haldane effect

A

Increased pO2 causes CO2 and H+ unloading

70
Q

Mitochondrial DNA

A

Codes for oxidative enzymes and mitochondrial ribosomes and tRNA needed for mitochondrial synthesis.

71
Q

Structure of HCG

A

Very similar to TSH, LH, FSH.

Can cause activation of these organs

72
Q

DNA polymerase 1

A

Has 5-3 exonuclease activity, can remove primer.

Others are 3-5

73
Q

Vitamin K does what…

A

Gamma carboxylates glutamate residues in liver

74
Q

Radiation induces..

A

DS DNA breaks and free radical formation

75
Q

Alpha helices in receptors

A

Have lots of nonpolar AA’s to span membrane

76
Q

How does aging affect collagen

A

Decreased synthesis, NOT decreased integrity or quality

UWorld Question Review (10 decks)

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