Biochem 67and 70-71. 66,68,69 look at sahaja

Question 1

Patient was in car accident. After given a blood transfusion, he develops hypotension and anaphylaxis. what does he have?

Answer 1

selective IgA deficinecy

Question 2

A 4 year patient was given radiation. Mom was worried about a specific thyroid cancer because she read it from MedMD. What carcinoma?
-intead the patient develops Ataxia, spider Angiomas, IgA deficiency. What genetic disorder the patient has?

Answer 2

ATM gene defect–> DNA double strand break can’t be repaired by non-homologous end joining–> Ataxia telangiectasia

Question 3

Kids with no thumb, increased chance for AML. What disease and what genetic abnormality?

Answer 3

Can’t do non-homologous end joining.

Question 4

Homologous and non-homologous joining are used to repair DNA strand break. What does non-homologous joining mean?

Answer 4

Means no need to use sister chromatid as template. Non-homo is used after ionizing radation and ROS injury

Question 5

Patient has endometrial, ovarian and skin cancer with CRC.

1. What genes are mutated
2. These genes work in what phase of cell cycle?
3. name the only chemo drug that works in that phase of cell cycle?

Answer 5

1. mismatch repair genes MLH1, MSH2
2. G2 rapidly divide –> skin
3. bleomycin (repair the DNA strand break by ROS)

Question 6

A girl always have sunburn easily even if she put sunscream. She has areas of hypopigmentation, hyperpigmentation, telangiectasias and atrophy. What does she has and what back ground?

Answer 6

Xeroderma pigmentosum
cannot repair pyrimidine dimer.

called nucleotide excision repair
by specific endonuclease

Question 7

What is nucletoide?

Answer 7

Base+ sugar + P

Question 8

what enzymes do you use if you have altered base?

Answer 8

base specific-glycosylase (remove the altered base)

Question 9

When does NER and BER occurs? and mismatch repair?

Answer 9

NER in G1 = gorwing cells
BER in all cell cycle
Mismatch? G2

Question 10

In NER, endonuclease cleave at 5’ end. why?

Answer 10

because 3’ end is OH. and 5’ end has triphosphate group for the attachement of incoming new nucleotide.

Question 11

What is abacavir MOA?

Answer 11

it’s a NRTIs. They are nucleoside that are converted to nucleotide by viral and cellular kinases. But they do not have 3’OH group. so DNA synthesis cannot continued –> chain termination.

Question 12

DNA synthesis is from?

Protein synthesis is from?

Answer 12

5’ to 3’

N terminus to C terminus

Question 13

Patient with homocysteine methyltransfer deficiency has decreased level of this aa and this aa is essential for starting protein synthesis in eurkaryotes.

Answer 13

methionine

Question 14

What is the neutrophil chemotaxis in prokaryotes? Hint: it is also an mRNA start codon.

Answer 14

fMET (N-formylmethionine)

Question 15

what does 3’ end of tRNA have?

Answer 15

Can Carry Amino acid

3’ CCA

Question 16

This poor tRNA cannot bind to ribosome. what’s defective?

Answer 16

T arm

Thymine, pseudouracil cytosine

Question 17

pseudouracil is found in?

Answer 17

T arm

Question 18

dihydrouracil found in?

Answer 18

D –> Darm

Question 19

Methionine comes in and cannot seem to attach to tRNA. who is responsible given that there is normal activity of amnioacyl-tRNA synthetase.

Answer 19

D arm!

Question 20

1. tRNA want to get charged/activated what does it use?

2. tRNA wants to go places (translocation) what does it use?

Answer 20

1. ATP

2. GTP

Question 21

if condon has AUG, what does anticondon has?

Answer 21

CAU

Question 22

Aminoglycoside inhibit what step of protein synthesis?

Answer 22

inhibit initiation

Question 23

this expired drug can cause fanconi syndrome which can lead to type II RTA. In term of its MOA, how does it specifically affect elongation?

Answer 23

inhibit binding of tRNA to A site

Question 24

A 30 weeks pregnant living in burma with nuchal rigidity was given this drug. She develops aplastic anemia. Doctors decided to induce birth. Her baby is cyanotic, vomiting and abdominal distension. What drug is this? And what is its MOA

Answer 24

Cjhloramphenicol: inhibit peptidyl transferase –> inhibit transfer growing polypeptide to aa in A site –> thus inhibit 50S.

Question 25

1. A patient with Urethritis, cervicitis, conjunctivitis, reactive
   arthritis, PID is given ceftriaxone and this drug. What is it MOA?
2. Please give me one more antibiotics that acts the same? Hint: we use this for lung abscess.

Answer 25

1. inhibit translocation (growing peptide can’t be moved to P site).
2. Clindamycin

Question 26

List the stop condons that are recognized by _____.

Answer 26

AGA, UAA, UAG recognized by release factors

Question 27

Trimming is a phenomenon where N and C terminal polypeptides are removed. This enzyme secreted by pancreas as inactive. but it becomes active when it gets trimmed by what enzymes?

Answer 27

enteropeptidase in duodenum

Question 28

List two covalent alterations to turn the transcription on and off

Answer 28

on is acetylation

off is methylation

Question 29

Name the intracellular protein involved in CF pathology.

Answer 29

CF –> think protein folding –> chaperone

Question 30

BONUS! give a disease with ubiquitination problem (problem with posttransmodification)

Answer 30

alpha1antitrypsin deficiency

in AAT deficiency misfolded α1-antitrypsin accumulates in ER and damages hepatocytes

Question 31

what’s kozak sequence?

Answer 31

sequence that has AUG in eukaryotes for inititation

Question 32

what’s ShineDalgarno Sequence

Answer 32

sequence upstream of AUG in prokaryotes. recognized by fMet