18

Question 1

what are the purines

Answer 1

pure As Gold

Question 2

what are the pyrimidines

Answer 2

CT

Question 3

whats a nucleotide

Answer 3

phosphate group, sugar, and base

Question 4

to what end are new nucleotides added

Answer 4

3´

Question 5

how many bonds between G and C

Answer 5

3

Question 6

how many bonds between A and T

Answer 6

2

Question 7

what type of bon delinks the base pairs

Answer 7

covalent

Question 8

what kind of bond is in the sugar phosphate backbone

Answer 8

peptide bonds

Question 9

what free structure is on the 5´end

Answer 9

free phosphate group

Question 10

what free structure is on the 3´end

Answer 10

unliked OH group on sugar backbone

Question 11

how many histones does DNA wrap around

Answer 11

8

Question 12

What is the name of the 8 core histones (and linker histone)

Answer 12

2 H2A 2 H2B 2 H3 and 2 H4 and linker histone H1

Question 13

at what part of the histones do the modifications occur

Answer 13

tail

Question 14

what is the main function of histone mofidicaiton

Answer 14

they regulate how tightly histones are bound to DNA and therefore whether the chromatin is in the form of a euchromatin or a heterochromatin

Question 15

What two molecules control the loops that histones create with DNA

Answer 15

Cohensins and CTCF

Question 16

how much more compact are chromosomes in metaphase compared to DNA itself

Answer 16

10,000x

Question 17

at what stage of the cell cycle is the chromosome the densest

Answer 17

during mitosis

Question 18

if the CC lasted a day, how long would interphase last

Answer 18

22-24 hrs

Question 19

if the CC lasted a day, how long would mitosis last

Answer 19

30-60mn

Question 20

Where does DNA replication start

Answer 20

at the origin of replication

Question 21

what form of chormatin is open

Answer 21

euchromatin

Question 22

what form of chormatin is closed

Answer 22

heterochromatin

Question 23

how long does the replication of the whole genome take

Answer 23

8-10 hrs

Question 24

to which end are nucleotides added

Answer 24

3’

Question 25

on what strand are Okazaki fragments added

Answer 25

lagging strand

Question 26

in what phase of the CC does DNA replication occur

Answer 26

S phase

Question 27

what is the function of topoisomerase and how does it work

Answer 27

Prevents supercoiling by making nicks in DNA to allow it to relax and DNA ligase sticks it back

Question 28

What are two types of antibiotics that target DNA replication

Answer 28

Fluoroquinolones and Trimethoprim - Sulfamethoxazole

Question 29

what bacteria is Fluoroquinolones used for? what enzyme does it target

Answer 29

targets topoisomerase in bacteria Aerobic Gram-positive Aerobic Gram-negative Some anaerobic Gram-negative species and M.tuberculosis

Question 30

list names of Fluoroquinolones

Answer 30

Nalidixic acid ciproflaxacin levofloxacin gemifloxacin

Question 31

in what ratio is Trimethoprim - Sulfamethoxazole found

Answer 31

1:5 T:S

Question 32

what bacteria is Fluoroquinolones used for? what step does it target

Answer 32

Aerobic Gram-positive and Gram-negative species Target nucleotide synthesis

Question 33

on average when a cell divides. how many mistakes are made

Answer 33

12-20

Question 34

What are the two major types of defects in DNA

Answer 34

single strand defect | double strand defect

Question 35

what is base excision repair

Answer 35

If you have deaminated cytosine it becomes uracil. Uracil DNA glycosylase removes the U then sugar phosphate is removed And DNA pol adds new nucleotides and DNA ligase seals the nicks

Question 36

what is nucleotide excision repair

Answer 36

If you have ionizing radiaiton, you can get pyrimidine dimers being fomed not at the sugar phspohate sude base bs other base. Pyrimidine dimer elision. Super dangerous because RNA cant be made correctly. Basically nuclease breaks DNA at 12 nucletoide stretch in bacteria and 20 nucleotdeis in humansm then helicase removes that nucletodie strech and the DNA pol and DNA ligase replaces that strand with a normal copy

Question 37

what is mismatch repair

Answer 37

Two main enzymes • MutS binds to mismatched base pair • MutL scans nearby DNA for nick and triggers strand removal to the Mismatch Muts and mut l bind to msitake mutl scans dna looking for a gap, causing remocal of the strand from the gap to the error and replaces it with a new strand.

Question 38

what is non homologous end joining

Answer 38

accidental ds break loss of nucleotides due to degradation from ends it is linked together despite missing bases Even though its not the same, its reparied and its function structurally perfectly well.

Question 39

what is non homologous end joining

Answer 39

accidental ds break loss of nucleotides due to degradation from ends Finds sister chromosome and copies it into the gap

Question 40

what gene is mutation within the NER that causes problems

Answer 40

Xeroderma pigmentosum (XP) mutation in a polymerase causing Skin cancer, cellular UV sensitivity, neurological abnormalities

Question 41

what gene is mutation within the mismatch repair that causes problems

Answer 41

Mutation in MutS, MutL | causes colon cancer

Question 42

what gene is mutation within the mismatch repair that causes problems

Answer 42

Mutation in MutS, MutL | causes colon cancer

Question 43

what gene is mutation within the homologous recombination repair that causes problems

Answer 43

BRCA2 mutation causes breast and ovarian cancer