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Review / Wrong Answers > 4/28 - UWorld > Flashcards

4/28 - UWorld Flashcards

1
Q

Enzymes of the TCA cycle that use B3 (NAD+)

A

Pyruvate dehydrogenase (pyruvate to acetyl CoA)

Isocitrate dehydrogenase (isocitrate to a-ketoglutarate)

Alpha-ketoglutarate dehydrogenase (a-ketoglutarate to succinyl CoA)

Malate dehydrogenase (malate to oxaloacetate )

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2
Q

Enzymes of the TCA cycle that use B2 (FAD)

A

Succinate dehydrogenase (succinate to fumarate)

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3
Q

What are the 2 enzyme deficiencies that may cause galactosemia, and which deficiency is more severe?

A

Galactokinase (Galactose -> galactose-1-P)

Uridyl transferase (Galactose-1-P –> Glucose-1-P) . . . More severe

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4
Q

Presentation of Galactosemia

A

Mild form (galactokinase deficiency) - infantile cataracts

Severe form (Uridyl transferase deficiency) - cataracts, jaundice, hepatomegaly, lethargy, intellectual disabilities)

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5
Q

Enzyme deficiency in sideroblastic anemia

A

ALA synthase

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6
Q

Affected enzymes in lead poisoning

A

Ferrochelatase and ALA dehydratase

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7
Q

Affected enzyme, presentation, and treatment of acute intermittent porphyria

A

Porphobilinogen deaminase

Symptoms – 5 P’s

Painful abdomen, Port wine colored urine (due to increase PGB), Polyneuropathy, Psychological disturbances, Precipitated by drugs (CYP450 inducers), alcohol, and starvation

Treatment: Glucose + heme = inhibition of ALA synthase

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8
Q

Affected enzyme and presentation of porphyria cutanea tarda

A

Deficiency of Uroporphyrinogen carboxylase

Symptoms - Blistering cutaneous photosensitivity and hyperpigmentation

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9
Q

What substance is responsible for inhibition of carnitine acyl transferase, thus inhibiting beta oxidation?

A

Malonyl CoA - in order to inhibit the breakdown of newly synthesized fatty acids

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10
Q

What are causes of homocysteinuria?

A

Homocysteine can be converted to methionine via methionine synthase + B12 or to cystathionine via cystathionine synthase B6

Homocysteinuria caused by deficiency in cystathionine synthase, decreased affinity of cystathionine synthase for B6, or methionine synthase

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11
Q

Presentation of homocysteinuria

A

Homocystine is a prothrombotic, which may lead to prematyre acute coronary syndrome

Homocysteine in urine

Marfanoid habitus

Ocular changes (downward and inward lens subluxation – vs. Marfan which is upward)

Kyphosis

Intellectual disability

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12
Q

Cause of cysteinuria

A

Defect in COLA transporter of proximal convoluted tubule (cystein, ornithine, lysine, arginine)

Can lead to hexagonal cysteine stones

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13
Q

Which lymph nodes does the skin drain to?

A

Above the umbilicus - Axillary

Below the umbilicus - Superficial inguinal

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14
Q

What lymph node does the rectum drain to?

A

Upper rectum - inferior mesenteric

Lower rectum - internal iliac

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15
Q

What lymph node does the anal canal drain to?

A

Above the pectinate line - internal iliac

Below the pectinate line - superficial inguinal

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16
Q

What lymph node does the scrotum drain to?

A

Superficial inguinal

17
Q

What lymph nodes do the testes drain to?

A

Para-aortic

18
Q

What lymph node does the uterus drain to?

A

Para-aortic

19
Q

What lymph node does the vagina drain to?

A

Internal iliac

20
Q

Which HLA genes encode for MHC class I and MHC class II

A

MHC I - HLA-A, HLA-B, HLA-C

MHC II - HLA-DP, HLA-DQ, HLA-DR

21
Q

What disease is associated with HLA-B27

A

Seronegative arthropathies - PAIR

Psoriatic arthritis, ankylosing spondylitis, irrititable bowel disease, reactive arthritis (Reiter)

22
Q

What HLA genes are associated with DM type I

A

HLA-DR3 and HLA-DR4

23
Q

How do NK cells work?

A

Use perforin and granzymes to induce apoptosis

Part of innate immune system because they do not need MHC to be activated

24
Q

What cytokines enhance NK cells?

A

IL-2, IL-12, IFN-a, IFN-b

25
Q

What are the surface markers of NK cells?

A

CD16, CD56

CD16 binds to the constant (Fc) region of antibodies - helps to recognize and kill IgG-coated cells via antibody-dependent cell-mediated cytotoxicity (ADCC)

26
Q

What cytokines cause differentation into Th1 cells and what cytokines do Th1 Cells produce?

A

IL-12 from macrophages causes differentiation

Th1 cells produce IL-2 and IFN-y

27
Q

What cytokines cause differentation into Th2 cells and what cytokines do Th2 Cells produce?

A

Differentiation via IL-4

Produces IL-4, IL-5, and IL-10

28
Q

What is the process of activation of T-cells

A

1st signal - MHC + antigen on APC binds to TCR on T-cells

2nd signal - B7 (CD80/86) binds to CD28 on T-cells

29
Q

Describe the activation process of B-cells

A

Endocytosis of antigen by B-cell

(1st signal) Antigen presented to T-cell via MHC II

(2nd signal) CD40 on B-cells binds to CD40L on Th cells

Th2 cells generate IL-4 and IL-5 for B class switching

30
Q

Surface markers of B-cells

A

CD19, CD20, CD21, IgM, IgD

Review / Wrong Answers (140 decks)

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