Biotechnology

Question 1

Describe how genetic fingerprinting may be carried out on a a sample of DNA

Answer 1

DNA is cut;
using restriction enzyme;
Use electrophoresis;
Separates according to length/mass;
Southern blotting/transfer to (nylon) membrane;
Make single-stranded;
Apply probe;
Radioactive or fluorescent;
Reference to tandem repeats/VNTRs/minisatellites;Autoradiography/eq;

Question 2

List Biotechnology Techniques related to manipulating DNA

Answer 2

• Restriction Enzymes
• DNA Ligase
• Reverse Transcriptase

Question 3

List biotechnology techniques related to analysing DNA

Answer 3

• PCR
• DNA Sequencing
• Restriction Mapping
• Electrophoresis
• Southern Blot
• Genetic Fingerprinting

Question 4

List biotechnology techniques related to cloning DNA

Answer 4

• Vectors
• Transformation
• Marker Genes

Question 5

What do restriction enzymes do?

Answer 5

Cut DNA at specific sites.

Question 6

What are sticky ends, as created by restriction enzymes?

Answer 6

Sticky ends are ends with exposed bases that can anneal onto other sticky ends that have been cut with the same enzyme)

Question 7

What are blunt ends, as created by restriction enzymes?

Answer 7

Ends with no exposed bases

Question 8

What is the place where restriction enzymes are cut called?

Answer 8

Recognition sites

Question 9

What is DNA Ligase?

Answer 9

An enzyme that joins two nucleotides together. Often used to join together complementary restriction fragments

Question 10

What is Reverse Transcriptase?

Answer 10

an enzyme which synthesised DNA from an RNA template

Question 11

Where does Reverse Transcriptase come from?

Answer 11

Retroviruses

Question 12

What is the kind of DNA created by Reverse Transcriptase from mature mRNA called?

Answer 12

cDNA (Complementary DNA)

Question 13

How can Reverse Transcriptase be used in biotechnology?

Answer 13

• Make genes without introns to splice into plasmids
• Makes a stable copy of a gene (less readily broken down than RNA)
• Makes genes easier to find

Question 14

Explain how the strands of DNA are separated during the PCR

Answer 14

by heating to break the H-bonds (between complementary bases)

Question 15

in PCR why are primer required

Answer 15

to allow the DNA polymerase to attach
start addition of nucleotides
mark start and end of sequence to be copied
prevents strands re-joining

Question 16

In PCR two different primers are required, why?

Answer 16

because the sequences at the ends of the target sequence are different or
one is at the beginning and one at the end;

Question 17

Describe how a gene can be isolated from human DNA.

Answer 17

Using restriction endonuclease/enzymes to cut DNA at a specific place

Question 18

Why is modified deoxy nucleotide added to test tubes during Sanger Sequencing?

Answer 18

To stop further synthesis of DNA, as it cannot form phosphodiester bonds

Question 19

How is DNA sequencing read on the electrophoresis gel?

Answer 19

From bottom to top

Question 20

What is a restriction map?

Answer 20

A diagram of a piece of DNA marked with the location of sites where it is cut by restriction enzymes

Question 21

Explain Southern Blotting

Answer 21

• Hydrogen bonds broken between DNA bases
• Nylon and stack of paper towels weighted down on top of gel. Negative DNA drawn to positive nylon
• Nylon removed and DNA fixed by UV, then mixed with probes
• Probes anneal by complementary base pairing
• Visualised by fluorescent light or autoradiography

Question 22

What is a vector?

Answer 22

A length of DNA that carrier the desired gene into a host cell

Question 23

What are marker genes?

Answer 23

Genes used to find which cells have taken up the hybrid vector

Question 24

What are the two types of marker genes in a Vector?

Answer 24

• Antibiotic Resistance Gene

- GFP

Question 25

Why do we need an antibiotic resistance marker gene on top of the GFP gene?

Answer 25

So after the gene transformation, the cells can be cultured in that antibiotic to determine which cells have taken up the plasmid

Question 26

Give two characteristic features of stem cells.

Answer 26

Will replace themselves/keep dividing/replicate

Undifferentiated/can differentiate/develop into other
cells/totipotent/multipotent/pluripotent