Usmle - Day 6 - Flex1

Front 1

Describe the lifecycle of a chylomicron

Back 1

1) FFA+TGs enter intestine
2) Form chylomicrons in the enterocytes
3) Nascent chylomicron has B-48 receptor
4) HDL adds ApoE and apoC-II
5) Chylomicron binds to endothelial LPL via apoC-II
6) Hydrolyzed glycerol + FFA
Glycerol gets converted to G3P and used in VLDL. FFA gets converted to TAGs for storage in fat and are oxidized in muscle for energy
7) apoCII is returned to HDL
8) Chylomicron remanant binds to liver via apoE

Front 2

HDL provides what apo proteins

Back 2

apoC-II
apoE

Front 3

How are VLDL levels related to HDL levels

Back 3

Increase in VLDL leads to decrease in HDL

Front 4

Mediators of hormone sensitive LPL

Back 4

Insulin inhbit

ephinerphine and GH stimulate

Front 5

Lead poisoning
Enzyme defect
Accumulated substrate
Sx

Back 5

ALA dehydratase & ferrocheletase

Protoporphyrin ( in blood)

Sx
Microcytic anemia, GI and kidney disease
Children - mental deterioration
Adults - headache, memory loss, demyelination (exposure to battery/ammunition/radiator factory)

Lead lines
Encephalopathy and Erythrocyte basophilic stippling
Abdominal colic and sideroblastic anemia
Drops - wrist and foot drop

Front 6

Prophyria cutanea tarda
Enzyme defect
Accumulated substrate
Sx

Back 6

Uroporphyrinogen decarboxylase

Build up of Uroporphyrinogen III (tea colored pee)

Sx: Blistering cutaneous photosensitivty

Front 7

Acute Intermittent porphyria
Enzyme defect
Accumulated substrate
Sx
Treatment

Back 7

Prophobilinogen deaminase (aka Uroporphyrinogen synthase)

Buildup of porphobilinogen, ALA, uroporphyrin (urine)

Sx (5 Ps)
Pink urine
Painful abdomen
Polyneruopahty
Precipitated by drugs
Psychological Distrubances

Treatment: heme and glucose, which inhibit ALA synthase

Front 8

Patient with abdominal pain + neuropyschiatric change + urine change on standing =

Back 8

Acute intermittent porphyria

Front 9

Vitamin whos stores last for years

Back 9

B12

Front 10

CAAT is used for what?

Back 10

Transcription (promotor)

Front 11

TATA is used for what?

Back 11

Transcription (promotor)

Front 12

Shine-Dalgarno is used for what?

Back 12

Translation

Front 13

2nd most common cause of mental retardation

Back 13

Fragile X

Front 14

Friedreich's ataxia

Back 14

Autosomal recessive trinucleotide repeat GAA
Defect in the frataxin gene, leading to mitochondrial impairment (impaired mitochondrial iron homeostasis/cells more prone to apoptosis)
Sx: Pes cavus, hammer toe, ataxia, hypertrophic cardiomyopathy (cause of death), nystagmus, frequent falling
Degeneration of:
DRG, spinocerebellar/corticospinal tracts, posterior column

Presents in childhood w/ kyphoscoiosis

Front 15

Mutation in Beta-thal affects what?

Back 15

mRNA transcription, processing, and translation
Point mutations in splicing sites and promoter sequences

Front 16

Rotenone does what?

Back 16

Inhibits electron transport chain

Front 17

What kind of receptor does PRL work on?

Back 17

TRK

Front 18

C. difficile toxin

Back 18

A (enterotoxin) - causes neutrophil recruitment, leading to inflammation, loss of water (diarrhea), and mucosal death

B (cytotoxin) - actin depolymerization, loss of cell cytoskeleton, necrosis