Exam 3 DNA stuff

Question 1

prokaryotic chromosomes

Answer 1

-circular
-smaller size
-only 10% genome noncoding, asexual reproduction

Question 2

eukaryotic chromosomes

Answer 2

-linear
-more than one
-larger bc 95% genome noncoding, sexual reproduction

Question 3

DNA

Answer 3

-deoxyribonucleic acid, polymer of nucleotides
-antiparallel strands
-form double helix

Question 4

nucleotides made of

Answer 4

-pentose sugar (deoxyribose)
-phosphate (give - charge)
-nitrogenous base

Question 5

nitrogenous base

Answer 5

cyclic compounds, come in two forms:
-purine
-pyrimidine

Question 6

purines

Answer 6

-adenine
-guanine

Question 7

pyrimidine

Answer 7

-thymine
-cytosine

Question 8

double helix

Answer 8

-regular B form and irregular A form

Question 9

B form

Answer 9

-regular
-10 base pairs for one helical turn

Question 10

A form

Answer 10

11 base pairs in one helical turn

Question 11

Bacteria condensing of DNA

Answer 11

facilitated by supercoiling DNA into domains

Question 11

supercoiling

Answer 11

-negative manner
-twisted around axis in opposite direction of right handed helix
-facilitated by topoisomerase

Question 12

topoisomerase

Answer 12

-insert or remove supercoiling (2 classes)

Question 13

Class 1

Answer 13

single protein causes a nick in one strand

Question 14

Class 2

Answer 14

multi subunit protein complex causes nicks in both chromosome strands

Question 15

DNA gyrase

Answer 15

most common class 2 topoisomerase insertion

Question 16

what do nicks cause

Answer 16

coiling to occur, uses energy to twist and release

Question 17

how is supercoiling performed?

Answer 17

in domains for efficiency bc you dont need entire genome expressed at one time

Question 18

domains

Answer 18

-histone like proteins that have positively charged proteins that bind DNA and stabilize individual domains

Question 19

largest cell compenents

Answer 19

peptidoglycan then DNA

Question 20

eukaryotic condensing

Answer 20

DNA wrapped around clusters of histones (8) forming nucleosomes

Question 21

Prokaryotic condensing

Answer 21

condense DNA into nucleoid

Question 22

are histone- like proteins similar to histones

Answer 22

no, only similar in that they both have a positive charge

Question 23

Archaea condensing

Answer 23

use histones and/or topoisomerase

Question 24

archaea histones

Answer 24

-share histone fold that is the central region necessary for forming nucleosomes -only forms clusters of 4 not 8

Question 25

archaea topoisomerase

Answer 25

most common still DNA gyrase however hyperthermophiles have reverse DNA gyrase (hypertherm also still have monolayer)

Question 26

reverse DNA gyrase

Answer 26

positive supercoiling, much tighter because of the higher temp, adds rigidity

Question 27

Do humans have DNA gyrase?

Answer 27

No, makes it a good target for antibiotics

Question 28

antibiotics that target DNA gyrase

Answer 28

Quinolones: ciprofloxacin, nalidixic acid