topic 888

Question 1

why can thee transfeered DNA be transcribed/ translated into proteins of tthe recipent

Answer 1

the genetic sequence is universal
so are the transcription and translation mechanism

Question 2

what is recombinant DNA

Answer 2

the transfer of DNA fragments from one organism to another

Question 3

what is used convert mRNA into cDNA

Answer 3

reverse transcriptase

Question 4

how’s fragments of DNA made

Answer 4

• conversion of mRNA to cDNA using reverse transcriptase.
• using restriction enzymes to cut the fragments containing the desired gene from DNA
• creating a gene in a gene machine

Question 5

how are fragments of DNA amplified

Answer 5

in vitro and in vivo techniques

Question 6

what type of method is polymerase chain reaction (PCR)

Answer 6

in vitro

Question 7

what does the process of using reverse trancriptase to obtain a DNA fragment include

Answer 7

mRNA which codes for the required protein is isolated
- DNA nucleotides bind to the mRNA
- reverse transcriptase uses mRNA to synthesise cDNA

Question 8

what does cDNA stand for

Answer 8

complimentary DNA

Question 9

what type of enzyme is used to cut a fragment containg the desired gene from DNA

Answer 9

restriction endonucleases

Question 10

what is the role of restriction endonucleases

Answer 10

they recognise specific palindromic sequences of DNA. and they cut DNA at these places

Question 11

what is meant by a palindromic sequence of DNA

Answer 11

the base pairs are read the same in opposite directions

Question 12

where do restriction endonucleases cut at

Answer 12

at specific recognition sequences

Question 13

what bonds do restriction endonucleases break

Answer 13

phosphodiester bonds

Question 14

what is the active site of restriction endonucleases complimentary to

Answer 14

the shape of the recognition sequence

Question 15

what do sticky ends do

Answer 15

they bind to a piece of DNA that has sticky ends which have a complimentary sequence

Question 16

what enzyme binds to sticky ends together

Answer 16

ligase

Question 17

how is a gene created in a gene machine

Answer 17

synthesis fragments of DNA from scratch witthout using an existing DNA template.

Question 18

what are advantages of using mRNA to make DNA fragments rather than restriction enzymes

Answer 18

more mRNA in cell comparedd to DNA
bacteria cant remove introns

Question 19

what is an example of an in vitro method

Answer 19

polymerase chain reaction

Question 20

what is a promoter region

Answer 20

DNA sequences that tells RNA polymerase to start producing mRNA

Question 21

what is a terminator region

Answer 21

tells RNA polymerase when to stop

Question 22

what happens to the number of DNAA in PCR

Answer 22

it doubles

Question 23

what is in the reaction mixture of a polymerase chain reaction

Answer 23

DNA sample
free nucleotides
primers
DNA polymerase

Question 24

what are primers

Answer 24

are short pieces of DNA that are complentary to the bases at the start of the fragment

Question 25

what is taq polymerase

Answer 25

a different version of DNA polymerase

Question 26

at wwhat temperature are the hydrogen bonds broken

Answer 26

95 degrees

Question 27

why is the DNA heated to 95 degrees

Answer 27

to break the hydrogen bonds

Question 28

why is the mixture cooled

Answer 28

so that the primers can bind/anneal to the exposed bases

Question 29

what temperature id the mixture cooled to

Answer 29

50-65 degrees

Question 30

why is the reacttion mixture then reheated to 72 degrees

Answer 30

so that its thee optimum temperature for DNA polymerase

Question 31

what is the role of DNA polymerase in PCR

Answer 31

it joins the adjacent nucleotides forming phosphodiester bonds

Question 32

what is the optimum temperature of DNA polymerase

Answer 32

72 degrees