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Biology Revision Year 2 > Gene Technology > Flashcards

Flashcards in Gene Technology Deck (54)
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1

What is a Palindromic site?

its read the same forwards and backwards

(eg) CTTAAG to GAATTC)

2

What is the role of restriction enzymes?

They cut DNA at specific Palindromic sites called restriction sites

3

What does using a restriction enzyme leave DNA with?

sticky ends (unpaired bases)

4

What does reverse transcriptase do?

mRNA -------> cDNA

5

What does cDNA not have?

introns (made from mRNA post splicing)

6

What enzyme does DNA ------> mRNA?

RNA Polymerase

7

Describe Artificial Synthesis of a gene.

use a gene machine to make DNA from scratch, making oligonucleotides, join theses together to make a synthetic gene.

8

What is an oligonucleotide?

a sequence of around 25 nucleotides

9

What are the three ways we can isolate target genes?

gene machine, reverse transcriptase or restriction enzymes

10

What is PCR used for?

to amplify a gene

11

What are the 4 components of PCR?

DNA sample, free nucleotides, primers, DNA polymerase

12

describe the 3 steps of PCR

heat up to 95 degrees
cool to 50 degrees
heat to 70 degrees

13

Why do we heat the sample to 95 degrees

break the H+ bonds between so they are single stranded

14

Why do we cool the sample to 50 degrees

allows the primer to attach by complementary base pairing to the exposed strand - making a double strand - so DNA polymerase can bind to the double stranded section

15

Why do we heat the sample back up to 70 degrees

there is a higher kinetic energy increasing enzyme action

16

why can the DNA polymerase work at high temperatures?

extracted from thermophillic bacteria

17

What is a primer?

Short sequence of DNA which is complementary to the target DNA

18

Name three ways we can isolate a target gene

restriction enzymes, Gene machine, reverse transcriptase

19

What charge is DNA?

negative

20

Describe the process of electrophoresis

attach a fluorescent label to DNA
put labelled DNA fragments into the well at the negative end
turn on current
DNA is attracted to the positive electrode

21

How can we distinguish the length of DNA from electrophoresis?

smaller fragments move faster (therefore further over any given time)

22

How can you calibrate the scale in electrophoresis?

use pieces of DNA of a known length

23

How can we insert the isolated target gene into a vector?

use the same restriction enzyme so that the sticky ends are complementary
DNA ligase makes recombinant DNA

24

How can the vector be inserted into the plasmid?

ice cold calcium chloride and a heat shock to make a transgenic/ transformed organism

25

How can scientists identify transformed/transgenic organisms?

marker genes, fluorescence, antibiotic resistance

26

Why do we then culture the transformed/ transgenic organism (bacteria)

the organism transforms/ translates the recombinant DNA
to make desired protein eg) insulin

27

What is gene therapy?

altering faulty alleles that cause genetic disease

28

How can we silence a genetic disorder caused by a dominant allele? (eg) Huntingtons)

sufferer is heterozygous
use a vector to add a DNA fragment into dominant allele
this prevents transcription
recessive allele expressed

29

How can we silence a recessive allele disease (eg) cystic fibrosis)

sufferer is homozygous
use a vector to add the functional allele to DNA
dominant allele will be expressed

30

What is Germ line gene therapy?

Change to the alleles of Gametes (currently illegal)