Molecular I

Question 1

DNA and histone charges

Answer 1

DNA - negative

histone - positive

Question 2

histone AAs

Answer 2

arginine and lysine

Question 3

H1 histone

Answer 3

linker

binds nucleosone - stabilizing chromatin

Question 4

DNA and histone synthesis

Answer 4

S phase

Question 5

heterochromatin

Answer 5

dense DNA
inactive

ex. barr bodies - inactive

Question 6

euchromatin

Answer 6

loose DNA

active

Question 7

DNA methylation

Answer 7

inhibit transcription

Question 8

CpG islands

Answer 8

DNA methylation

-inhibit transcription

Question 9

nucleosome

Answer 9

DNA wrapped around histone

Question 10

histone methylation

Answer 10

repress DNA transcription

Question 11

histone acetylation

Answer 11

relax DNA coil

-allow transcription

Question 12

purine

Answer 12

A
G
2 rings

Question 13

pyrimidine

Answer 13

C
T
U
1 ring

Question 14

bonds purine vs. pyrimidine

Answer 14

C-G = 3
A-T = 2

CG stronger - higher melting temp

Question 15

AA for purine synthesis

Answer 15

glycine
aspartate
gultamine

Question 16

nucleoside vs. nucleotide

Answer 16

side - base and sugar

tide - base, sugar, and phosphate

Question 17

hydroxyurea

Answer 17

inhibit ribonucleotide reductase

-inhibit pyrimidine pathway

Question 18

6 mercaptopurine

Answer 18

inhibit de novo purine synthesis

purine synthesis

Question 19

5 fluorouracil

Answer 19

inhibit thymydilate synthetase

pyrimidine synthesis

Question 20

methotrexate

Answer 20

inhibit DHFR

Question 21

trimethoprim

Answer 21

inhibit DHFR

Question 22

pyrimethamine

Answer 22

inhibit DHFR

Question 23

leflunomide

Answer 23

inhibit dihydroorate DH

Question 24

mycophenolate

Answer 24

inhibit IMP DH

purine synhesis

Question 25

ribavirin

Answer 25

inhibit IMP DH purine synthesis

Question 26

temporary base in pyrimidine synthesis

Answer 26

orotic acid

Question 27

allopurinol

Answer 27

inhibit xanthine oxidase

Question 28

febuxostat

Answer 28

inhibit xanthine oxidase

Question 29

probenecid

Answer 29

increased uric acid excretion in urine

Question 30

adenosine deaminase deficiency

Answer 30

major cause auto rec SCID excess ATP and dATP - imbalanced nucleotide pool prevent DNA synthesis - decreased lymphocyte count

Question 31

redundant genetic code

Answer 31

most AA coded by multiple codons

Question 32

lesch nyhan syndrome

Answer 32

defective purine salvage absent HGPRT excess uric acid clinical intellectual disability, self mutilation, aggression, hyperuricemia, gout, dystona

Question 33

tx lesch nyhan

Answer 33

allopurinol | febuxostat

Question 34

helicase

Answer 34

unwind DNA

Question 35

single strand binding protein

Answer 35

prevent reannealing of separated DNA strands

Question 36

fluoroquinolones

Answer 36

inhibit topoisomerase II - DNA gyrase

Question 37

topoisomerase

Answer 37

fix supercoliing

Question 38

primase

Answer 38

add RNA primer - on which DNA polymerase III can initiate replication

Question 39

DNA polymerase III

Answer 39

prokaryote only 5 > 3 synthesis 3 > 5 exonuclease

Question 40

DNA polymerase III vs. I

Answer 40

III - elongate leading strand - 5 > 3 synthesis -and 3 > 5 exonuclease I - degrade RNA primer - replace with DNA -and 5 > 3 exonuclease

Question 41

direction of synthesis of DNA

Answer 41

read 3 > 5 | synthesized 5 > 4

Question 42

DNA polymerase I

Answer 42

excise RNA primer with 5 > 3 exonuclease

Question 43

DNA ligase

Answer 43

formation of phosphodiester bonds within strand of dsDNA join okazaki fragment

Question 44

telomerase

Answer 44

add DNA to 3' end chromosome avoid loss of genetic material RNA dependent DNA polymerase

Question 45

transition

Answer 45

purine to purine or pyr to pyr

Question 46

transversion

Answer 46

purine to pyr

Question 47

glucose not available to E. coli - but lactose is

Answer 47

lac operon activated low glucose - increased adenylyl cyclase - increase cAMP -activation of CAP - increased transcription high lactose - unbind repressor protein - increased transcription

Question 48

strong expression of lac operon

Answer 48

low glucose | high lactose