BIOCHEMISTRY - MOLECULAR

Question 1

DNA + Histone = ?

Answer 1

Nucleosome

Question 2

Positive charge of Histone (in nucleosome) is due to?

Answer 2

Lysine and Arginine

Question 3

Negative charge of DNA (in nuclosome) is due to?

Answer 3

Phosphate ions

Question 4

Transcriptionally inactive DNA (condensed, dark on EM)

Answer 4

Heterochromatin

Question 5

Transcriptionally active DNA (less condensed, light on EM)

Answer 5

Euchromatin

Question 6

This process discourages transcription

Answer 6

DNA/Histone methylation (addition of methyl group)

Question 7

This process encourages transcription

Answer 7

Histone acetylation (addition of acetyl group)

Question 8

Nucleoside composition

Answer 8

Base + (deoxy)ribose sugar

Question 9

Nucleotide composition

Answer 9

Base +(deoxy)ribose sugar + phosphate

Question 10

Purines include

Answer 10

Adenine

Guanine

Question 11

Pyrimidines include

Answer 11

Thymine
Cytosine
Uracil (RNA)

Question 12

Uracil + Methyl = ?

Answer 12

Thymine

Question 13

Purine has __ bond

Pyrimidine has __ bond

Answer 13

1) double

2) triple

Question 14

Enzymes involved in Pyrimidine synthesis

Answer 14

Carbamoyl phosphate synthetase II
Ribonucleotide reductase
DHF reductase
Thymidylate synthase
Dihydro-orate reductase

Question 15

Enzymes involved in Purine synthesis

Answer 15

PRPP synthetase
Inosine monophosphate dehydrogenase
Ribonucleotide reductase

Question 16

Drugs that inhibit nucleotide synthesis

Answer 16

Anti-neoplastic drugs
Antibiotics
Immunosuppressants

Question 17

Which drug inhibits dihydro-orate reductase?

Answer 17

Leflunomide

Question 18

Which drug inhibits dihydrofolate reductase?

Answer 18

Methotrexate
Trimethoprim
Pyrimethamine

Question 19

Which drug inhibits thymidylate synthase?

Answer 19

5 - Fluorouracil

Question 20

Which drug inhibits de novo purine synthesis?

Answer 20

6 - mercaptopurine

Question 21

Which drug inhibits inosine monophosphate reductase?

Answer 21

Mycophenolate

Ribavarin

Question 22

Which drug inhibits ribonucleotide reductase?

Answer 22

Hydroxyurea

Question 23

ADA deficiency has what kind of inheritance?

Answer 23

AUTOSOMAL RECESSIVE

Question 24

Lesch Nyhan syndrome has what kind of inheritance?

Answer 24

X LINKED RECESSIVE

Question 25

What accumulates in ADA deficiency?

Answer 25

Adenosine

Question 26

ADA deficiency is one of the major causes of _____

Answer 26

SCID

Question 27

What is absent in Lesch Nyhan syndrome?

Answer 27

HGPRT - Hypoxanthine Guanine PhosphoRibosyl Transferase

Question 28

What accumulates in Lesch Nyhan syndrome?

Answer 28

Uric acid

Question 29

Hyperurecemia
GOUT
Agression
Self mutilation
Intellectual disability
Dystonia
Orange sand urine (in diaper) seen in?

Answer 29

LESCH NYHAN SYNDROME

Question 30

Site of origin of replication

Answer 30

AT rich sequences

Question 31

Which enzyme unwinds DNA?

Answer 31

Helicase

Question 32

Removes super-coil

Answer 32

DNA topoisomerase

Question 33

Which makes RNA primers - or replication?

Answer 33

Primase

Question 34

Which enzyme elongates lagging strand until it reaches primer of preceding fragment?

Answer 34

DNA polymerase III

Question 35

Which enzyme degrades RNA primer and replaces with DNA?

Answer 35

DNA polymerase I

Question 36

Which enzyme joins Okazaki fragments?

Answer 36

DNA ligase

Question 37

Which enzyme adds telomere (TTAGGG) to 3’ ends of chromosomes to avoid loss of genetic material with every duplication?

Answer 37

Telomerase

Question 38

Which enzyme when deficient in cancer cells result in unlimited replication?

Answer 38

Telomerase

Question 39

Severity of mutation

Answer 39

Silent &laquo_space;missense &laquo_space;nonsense &laquo_space;frameshift