Unit8

Question 1

What are DNA probes

Answer 1

Short single-stranded pieces of DNA that can be marked as fluorescent or radioactive

that can identify alleles of genes and screen patients-

this can be used finding out hereditary diseases.

probes are created to have complimentary base sequence to the allele to screen for

Question 2

How do you DNA probes work

Answer 2

The patient the DNA sample is treated to make single-stranded

and them is mixed with the DNA probes

if the patient has the allele then the DNA probe will hybridise

and the label indicate the presence

Question 3

DNA hybridisation Denaturation

Answer 3

the Patients DNA is heated to create a single strand
This is done by heated the Patients DNA - denatured as it breaks apart the hydrogen bonds

Question 4

DNA hybridisation -annealing

Answer 4

The patient single-stranded DNA sample is mixed with the DNA probe and cooled to any complimentary sequences can align and form hydrogen bonds anneal

Some of the patient DNA samples will anneal back together but some will anneal to the DNA probe

Question 5

Locating specific alleles of a gene

Answer 5

1 )
to locate the specific allele the DNA base sequence must be known to create the DNA probe

for example this can be used by determining DNA sequencing techniques

2) The fragment of DNA company produced using a gene machine

3)This fragment can be amplified using a PCR

4)The label has been added either radioactive or a fluorescent label which emits light under a UV light

Question 6

What happens after hybridisation

Answer 6

DNA is washed so that any unbound DNA probes are washed away

Question 7

Genetic screening

Answer 7

This method can be used to screen for potential genetic disorders or the presence of cancer-causing oncogenes

It is possible to scream for multiple diseases simultaneously using an array where multiple different DNA probes are attached

Question 8

Personalised medicine

Answer 8

Is one key reason that having a DNA screen can be advantageous certain

drugs such as painkillers are more or less effective depending on your genotype it can also help determine the best dose which increases the effectiveness

Question 9

Genetic councillung

Answer 9

Type of social work
People can have their family history researched to consider the likelihood of them carrying any alleles linked to disease

before started a family or for their general health patients are informed of any potential risks to them levels or future offspring if they are to carry this alleles

Question 10

Three types of recombinant DNA tech

Answer 10

1) creating DNA fragments
2) genetic fingerprinting
3) genetic screening

Question 11

How to amplify fragments

Answer 11

PCR

Question 12

Amplifying dna fragments

Answer 12

Once the dna fragments have been isolated they need to be cloned to create large quantities this can be done vivo or vitro

Question 13

IN vitro

Answer 13

Fragments of DNA can be amplified in vitro
via the plymerorase chain reaction DONR by an automated machines

Question 14

PCR equipment list

Answer 14

Thermocyler
DNA fragments to be amplified
DNA polymerase
Taq pol.
Primers
DNA nucleotides 

Question 15

PCR denaturing

Answer 15

Temperature is 95°
Breaks
Hydrogen bonds and split the DNA into single strand

Question 16

PCR annealing

Answer 16

The temperature is then decrease to 55° so that the primers can attach

Question 17

synthesis during PCR

Answer 17

The enzyme DNA polymerase then attaches complimentary free nucleotides and makes a new strand

align next to each template -synthesis

the temperature is increased to 72° for this stage the optimum for taq DNA polymerase

Question 18

Advantages of
PCR

Answer 18

-Automated more efficient
-Rapid 100 billion copies of the union can be made within hours
-Doesn’t require living cells- Quicker and less complex Techniques needed

Question 19

VNTR’s

Answer 19

95% of human DNA is made up from entrance which consist of many variable number tandem repeats

Question 20

What is the probability of two individuals having the same VNTR

Answer 20

Very low however the more closely related you are the most similar VNTRs 

Question 21

Genetic fingerprinting

Answer 21

Genetic fingerprinting is the analysis of the VNTR or DNA fragments and this can be used to determine genetic relationships in the genetic variability population

Question 22

Genetic fingerprinting: collecting and extracting

Answer 22

Could be from blood body cells hair follicles if the DNA sample a small van PCR is used to amplify the amount of DNA

Question 23

Genetic fingerprinting: digesting

Answer 23

Restriction endonucleases that Cut the DNA into smaller fragments

enzymes which cut close to the target l VNTR are added

Question 24

Genetic fingerprinting: separation

Answer 24

Gel electrophoresis

The DNA samples and loaded into small wells in an agar
Gel
The gel is placed in a bigger liquid with an electrical voltage applied

DNA is negitivley charged so the DNA samples won’t move through the gel toward the positive end of the gel 

Question 25

Gel Electrophoresis

Answer 25

the agar gel creates resistance for the moving DNA

and smaller pieces of DNA CAN MOVE FASTER. And further along the gel

This is how the different lengths of dna are seprated

An alkaline is then added to separate the double strands of DNA

Question 26

Hybridisation - genetic finger printing

Answer 26

DNA Probes are short single stranded pieces of DMA complimentary in base sequence to the VNTRs

the porbes are radioactively or flourcently labelled

Different dna porbes are mixed with the single stranded dna VNTRs on the agar gel for them to bind

Question 27

Genetic finger printing: development

Answer 27

The agar gel will shrink and crack as it dries

and therefore the VNTRs and dna probes are transferer to a nylon sheet

The nylon sheet can then be exposed to x rays to visualise the position of radioactive gene probes

or UV light if the flourecent probes were used

Question 28

Genetic fingerprint analysis

Answer 28

The position of the DNA bands are compared to identity genetic relationships

the presence of a disease causing gene and to match
Unknown samples from a crime scene