3.8.4 Gene Technologies

Question 1

Determining the genome of simpler organisms allows

Answer 1

The sequences of proteins that derive from the genetic code of the organism to be determined

Question 2

Why can’t genome knowledge by easily translated into proteome

Answer 2

Non-coding DNA and regulatory genes

Question 3

Recombinant DNA tech involves

Answer 3

Transfer of DNA fragments from one organism or species to another

Question 4

Genetic code, transcription translation mechanisms are

Answer 4

Universal

Question 5

What can you do with transferred DNA

Answer 5

Translate into cells in transgenic organism

Question 6

In vivo method to amplify DNA

Answer 6

DNA insert attached to plasmid
Plasmid + Gene cut with same restriction enzyme to create complementary sticky ends Fragments incubated with plasmids
Base pairing takes place
Joined with DNA ligase which forms phosphodiester linkages

Question 7

What do restriction enzymes do

Answer 7

Cuts DNA into gene-sized pieces

Question 8

How is reverse transcriptase used to amplify DNA

Answer 8

Remove mRNA from cell
Add reverse transcriptase
Convert RNA into DNA
Forms double stranded DNA
PCR amplifies DNA

Question 9

Uses of genetic fingerprinting

Answer 9

Analysing DNA fragments that has been cloned by PCR + determining genetic relationships + genetic variability in a population
Forensic science
Medical diagnosis
Plant + animal breeding

Question 10

Uses of DNA probes

Answer 10

Locate specific alleles of genes
Screen patients for heritable conditions, drug responses, health risks

Question 11

What can be used to detect genetically modified cells in organisms

Answer 11

Marker genes

Question 12

What is meant by recombinant DNA technology

Answer 12

The transfer of DNA fragments from one organism to another

Question 13

Why does recombinant technology work

Answer 13

Genetic code is universal
Transcription and translation occur by the same mechanism and result in the same amino acid sequence across organisms

Question 14

Summarise the process of using reverse transcriptase to produce DNA fragments

Answer 14

mRNA complementary to the target Gene us used as a template
Mixed with free nucleotides which match up to complementary base pairs and reverse transcriptase which forms sugar-phosphate backbone, to create cDNA

Question 15

Summarise the process of inserting a DNA fragment into a vector

Answer 15

A plasmid used as vector
Cut with same restriction enzyme as DNA so ends are complementary
DNA ligase joins fragment and plasmid together

Question 16

Summarise the process of using enzymes to produce DNA fragments

Answer 16

Restriction endonucleases cut DNA at specific sequences
Different REs cut at different points but one RE will always cut same sequence
So using particular REs allow you to cut out certain Gene of interest

Question 17

Summarise the process of inserting a vector into a host cell

Answer 17

Cell transformation
Host cells mixed with vectors in an ice-cold solution + heat to encourage cells to take up the vectors
The cells can then be grown and the DNA fragment cloned

Question 18

Summarise the process of identifying transformed cells

Answer 18

Marker genes inserted into vectors along with DNA
When cells grow, UV light can be used to identify which cells have taken up the vector and which haven’t

Question 19

How can DNA probes be used to locate specific alleles

Answer 19

Probe designed so that its sequence is complementary to the allele you want to find
They are labelled, amplified using PCR, then added to a sample of single stranded DNA
The probe will bind if the allele is present

Question 20

3 applications of DNA probes

Answer 20

Screen someone’s DNA for particular heritable health condition
Identify a gene for use in genetic engineering
To predict how someone will respond to a drug

Question 21

Purpose of DNA hybridisation

Answer 21

Measure the degree of difference between 2 DNA stands
Can be used to compare someone’s DNA to a certain gene to see if they have it

Question 22

Summarise the process of DNA hybridisation

Answer 22

One DNA stand is labelled and mixed with an unlabelled comparison strand
More similar the strands, the more strongly they will bind
More energy required to break strands apart

Question 23

Benefits of genetic profiling

Answer 23

Identifying heritable diseases early
Treatment can be personalised

Question 24

What is genetic fingerprinting

Answer 24

Technique used to compare 2 DNA samples + determine weather they came from same individual

Question 25

How does genetic fingerprinting work

Answer 25

Every organism’s genome contains non-coding regions called variable number tandem repeats
Probability of 2 individuals having the same VNTRs is very low, so we can compare these areas to see if 2 DNA samples came from same person

Question 26

Summarise the process of genetic fingerprinting analysis

Answer 26

DNA sample obtained
VNTRs cut out using restriction enzymes
Labelled + cloned using PCR
Fragments separated using gel electrophoresis
Banding patterns of each sample can be compared

Question 27

How does gel electrophoresis work

Answer 27

DNA fragments are placed at one end of a slab of gel
Electrical current applied causing the DNA fragments to move towards the other end of the gel
Shorter fragments travel further
Pattern of bands created unique to every individual

Question 28

Applications of genetic fingerprinting

Answer 28

Forensics identify victims or suspects
Medical diagnosis e.g. to identify type of haemoglobin produced by an individual to diagnose sickle cell anaemia
Animal + plant breeding (breed out harmful alleles)