Biochem Part I

Question 1

Which aa are necessary to make purines

Answer 1

GAG - glycine, apartarte, glutamine

Question 2

Thymine has a what?

Answer 2

methyl group

Question 3

Difference between cytosine and uracil?

Answer 3

Deamination of cytosine => uracil

Question 4

Lesch Nyan syndrome?

Answer 4

Defective purine salvage due to absence HGPRT. Inability to convert hypoxanthine to IMP and guanine to GMP. Excess Uric acid => gout. HGPRT - hyperuricemia, Gourt, Pissed off (self mutilation), R - Retardation, T - dysTonia

Question 5

Which aminoa acids are coded by only 1 codon

Answer 5

Methionine (AUG), tryptophan (UGG)

Question 6

DNA Pol III and DNA Pol I functions? Which one has 3-5’ proof reading capabiltiies?

Answer 6

DNA Pol III: Elongates by adding deoxynucleotides to the 3’ end. Elongates lagging strand until it reaches primer of preceding fragment. Also has 3’-5’ proof eading capabilities. DNA pol 1 removes RNA primer and adds DNA.

Question 7

Mismatch repair is defective in?

Answer 7

HNPCC. Mismatch repair is normally => newly synthesized strand is recognized, mismatched nucleotides are removed and the gap is filled and resealed

Question 8

What is I-cell disease?

Answer 8

Inherited lysosomal storage disorder. Defect in phosphotransferase and unable to phosphorylate mannose. Mannose 6 phosphate necessary to traffic to lysosomes. Proteins are delivered extracellulary instead of lysosomes. PPT: Coarse facial features, clouded corneas, restricted joint movement, high plasma levels of lysosomes enzymes

Question 9

SRP direct proteins from where to where?

Answer 9

ribosomes to RER

Question 10

What drugs act on microbutubles

Answer 10

Microtubules Get Constructed Very Poory: Mebendazole Griseofulvin Colchicine (anti-gout) Vincristine/Vinblastine Paclitaxlel

Question 11

These stain for what? Desmin, Vimentin, GFAP, cytokeratin, neurofilaments

Answer 11

Muscle, connective tissue, glial cells, eptihelial cells, neurons

Question 12

Mnenomic for rememembering Collage locations

Answer 12

Be cool, read books - Bone (Skin, tendon), Cartilage, Reticulin, Basement membrane

Question 13

Type 1 collagen found in?

Answer 13

Bone, skin, tendon, ligaments, dentin, cornea, blood vesslels, SCAR TISSUE

Question 14

TYPE 2 collagen found in?

Answer 14

Cartilage, vitreous humor, nucleos pulposus

Question 15

Type 3 collagen found in? Type 4?

Answer 15

Reticulin - BLOOD VESSELS, Skin, lungs, intestine, bone marrow, lymphatics, and granulation tissue. Type 4 = basement membrane

Question 16

What gives elastin its elastic properties

Answer 16

Some lysine residues form covalent crosslinkes - 4 different lysines on 4 diferent elastin chains accomplished by extracellular lysyl hydroxylase

Question 17

Direct vs Indirect ELISA

Answer 17

Direct Elisa: use a test ANTIBODY to see if the antigen is present. Second antibody linked to a color generating enzyme is added to detect the antigen. Indirect Elisa: use a test antigen to see if the antibody is present. Second antibody coupled to color generating enzyme is added to detect the first antibody

Question 18

What is cre-lox system?

Answer 18

Inducibly manipulate genes at specific development points

Question 19

What is RNA interference?

Answer 19

dsRNA is synthesized complementary to mRNA of interest. dsRNA infected into human cells, separates and degrades target mRNA

Question 20

Isodisomy and Heterodisomy are from what kinds of error?

Answer 20

Isodisomy = meisos II, heterodisomy = meiosis I

Question 21

In Hardy Weinberg, the frequency of X linked recessive diseae in Males and females is what?

Answer 21

q= males, q^2 females

Question 22

What is Osler Weber Rendu Syndrome

Answer 22

Hereditary hemorrhagic telangiectasia - A/D. inherited disorder of blood vessels. Telangiectasia, recurrent epistaxis, skin discolorations, AVMs, BI bleeding, hematuria

Question 23

Mnemonic to remember X linked recessive

Answer 23

Be Wise Foods GOLD heeds silly hope. Bruton’s x ilnked agammaglobulinemia, wiskott-aldrich, Fabry disease, G6PD deficiency, Ocular albinism, Lesch-Nyan, Duscene and Becker muscular dystrophy, Hunter Syndrome, Hemophilia A and B, Ornithine transcarbamylase deficiency

Question 24

What is Fragile X syndrome? Defect? PPt?

Answer 24

Trinucleotide disorder = CGGn. X-linked defect affecting methylation and expression of FMR1 gene. 2nd most common cause of intellectual disability after Down syndrome. Findings: large testes, long face with long jaw, large everted ears, autism, mitral valve prolapse, short height, joint laxity, scoliosis

Question 25

Describe Duchenne Muscular Dystrophy - What kind of mutation, what gene, symptoms, diagnosis?

Answer 25

X-linked frameshift mutation => truncated dystrophin protein

Question 26

Mnemonic to remember the trinucleotide repeats

Answer 26

X-Girlfriends First Aid Helped Ace My Test = Fragile X = CGG, Friedrich’s Ataxia: GAA, Huntington CAG, Myotonic Dystrophy: CTG

Question 27

Williams syndrome ppt

Answer 27

Congenital microdeletion of short arm of 5. Distinctive elfin facies, intellectual disability, hypercalcemia (increased sensitivity to vit D), well-developed verbal skills, extreme friendlyliness. CV problems.