DNA and genetics

Question 1

what isomers are used to show that DNA is semiconservative (meselson stahl experiment)

Answer 1

Nitrogen 15 and 14

Question 2

replicon

Answer 2

region of DNA, that replicates from a single origin of replication.

Question 3

how many starting points does circular DNA have

Answer 3

one

Question 4

what is the oric

Answer 4

origin of replication i.e. initiation point

Question 5

oric is rich in……

Answer 5

adenine and thymine

Question 6

how many sequences are there in the oric and how many base pairs

Answer 6

11 and 245. three repetitions of 13 base pairs and four repetitions of 9 base pairs

Question 7

what protein complex helps recognize site of replication

Answer 7

origin recognition complex (ORC)

Question 8

what initiation factors bind to the ORC

Answer 8

cdc6 and DUP/Cdt1

Question 9

what do the initiation factors help load

Answer 9

MCM2–7 helicase complex

Question 10

what do S-CDK and DDK do

Answer 10

recruitment of the helicase components Cdc45 and the GINS complex and other functions

Question 11

what is activated at the start of S phase to begin replication

Answer 11

replicative helicase (composed of MCM2–7, Cdc45, and GINS)

Question 12

what enzyme begins dissolution

Answer 12

helicase

Question 13

what maintains the replication fork

Answer 13

single-stranded DNA binding proteins

Question 14

name four DNA polymerase substrates and four RNA and polymerase substrates

Answer 14

dATP, dGTP, dCTP, dTTP and ATP, GTP,CTP,UTP

Question 15

function of DNA polymerase I

Answer 15

replaces the primer with DNA

Question 16

function of DNA polymerase II

Answer 16

repair

Question 17

function of DNA polymerase III

Answer 17

main addition

Question 18

what enzyme seals the gap during replication

Answer 18

ligase

Question 19

what enzyme synthesizes primers

Answer 19

primase

Question 20

what helps hold DNA pol in place during addition

Answer 20

sliding clamp

Question 21

what enzyme helps relieve stress on DNA during unwinding

Answer 21

topiosomerase

Question 22

how does topiosomerase work

Answer 22

catalyzes the removal of superhelical turns from covalently closed DNA by a transient breakage and rejoining of phosphodiester bonds.

Question 23

what is the difference between TOP1 and TOP2

Answer 23

TOP1 cuts and repairs one strand while TOP2 cuts two

Question 24

where do we fine replication fork traps

Answer 24

in bacteria for termination of protein synthesis

Question 25

what repetitive sequence does telomerase add

Answer 25

TTAGGG

Question 26

what is TERT and TERC

Answer 26

TERT gene provides instructions for making one component of an enzyme called telomerase TERC is a component of telomerase

Question 27

what is telomerase composed of

Answer 27

ribonucleoprotein

Question 28

what chemical group is obtained during telomerase adding

Answer 28

free 3'OH groups due to hydrogen bond formation between the Gs

Question 29

what cells have high telomerase activity

Answer 29

cancer and germ cells

Question 30

what is retrovir (Zidovudine) used for

Answer 30

controls HIV

Question 31

what term is used to describe cells are only capable of a limited number of population doublings in culture

Answer 31

hayflick limit

Question 32

out of different types of DNA which has a low mutation rate

Answer 32

single copy DNA

Question 33

what type of DNA has a high degree polymorphism

Answer 33

repetitive DNA

Question 34

what sequences have no genes

Answer 34

highly repetitive DNA

Question 35

where are highly repetitive sequences found

Answer 35

heterochromatin in telomeres or centromeres

Question 36

for highly repetitive sequences the repeating unit is not conserved. true or false

Answer 36

false. it is conserved

Question 37

which sequences are the shortest a) moderately repetitive b) highly repetitive c) single copy

Answer 37

highly repetitive

Question 38

which sequences are involved | in organizing chromosome pairing during meiosis and recombination

Answer 38

highly repetitive

Question 39

what sequences are found in pericentromeric and telomeric heterochromatin regions

Answer 39

satellite DNA (highly repetitive)

Question 40

satellite sequences are a) unique to individuals b) unique to species c) same among all species

Answer 40

unique to species

Question 41

what sequences are dispersed through euchromatin

Answer 41

moderately repetitive

Question 42

which sequence regulates gene expression

Answer 42

moderately repetitive

Question 43

what do interspersed DNA have ability to

Answer 43

jump from one place to another in the genome

Question 44

what advantage to plasmids provide

Answer 44

antibiotic resistance

Question 45

what are the types of interspersed DNA

Answer 45

RNA and DNA transposons

Question 46

what is the difference between RNA and DNA transposons

Answer 46

RNA transposons require conversion of DNA to RNA and back to DNA again while DNA trasnposons do not require an RNA intermediate

Question 47

what are the two groups of RNA transposons

Answer 47

LTR and non-LTR elements

Question 48

DNA transposons are retroelements while RNA transposons are not

Answer 48

false. other way around

Question 49

are endogenous retroviruses(ERVs) LTR or non LTR elements

Answer 49

LTR elements

Question 50

what are endogenous retroviruses

Answer 50

These are retroviruses integrated into the vertebrate chromosomes and inherited from generation to generation as part of the host genome

Question 51

what are the types of non LTR elements

Answer 51

LINEs and SINEs (short and long interspersed nuclear elements)

Question 52

which of these has reverse transcriptase, SINEs or LINEs

Answer 52

LINEs, SINEs borrow them from other retroelements

Question 53

Alu sequence is a example of what

Answer 53

SINEs

Question 54

what type of transposons are in Ac/Ds elements of maize

Answer 54

DNA transposons

Question 55

what are the types of tandem repeats

Answer 55

micro, mega and mini satellite DNA

Question 56

what is another name for microsatellites

Answer 56

short sequence repeats (ssr)

Question 57

majority of minisatellites are 1) A-T rich 2) G-C rich 3) A-U rich

Answer 57

G-C rich

Question 58

where are minisatellites clustered in chromosomes

Answer 58

subtelomeric regions

Question 59

variable number of tandem repeats | (VNTR) are also known as

Answer 59

minisatellites

Question 60

telomeric repeats are 1) A-U rich 2) G-C rich 3) G-T rich 4) G-G rich

Answer 60

G-T rich

Question 61

where are subtelomeric repeats located

Answer 61

adjacent to the telomere

Question 62

where are hypervariable repeats located

Answer 62

within nuclear DNA or the D-loop of mitochondrial DNA

Question 63

hypervariable repeats are moderately polymorphic, true or false

Answer 63

false. they are highly so

Question 64

what is an examples of mega-satellites composed of coding repeats

Answer 64

RNA genes, and the deubiquitinating enzyme gene USP17

Question 65

what is another name for microsatellites

Answer 65

simple sequence repeats (SSRs)