Gene Tech 8.2

Question 1

What is the definition of genome?

Answer 1

All the different alleles an organism contains

Question 2

What is the definition of preotome?

Answer 2

The full range of protiens a cell can produce

Question 3

Why is it easier to determine the preotome of prokaryotic DNA than eukaryotic DNA?

Answer 3

-No introns or non coding DNA
-DNA not associated with histones
-DNA is usually a single circular loops

Question 4

Name one medical use of genome projects?

Answer 4

Some diseases result from people not being able to produce specific proteins eg insulin
Treatment can involve extracting the chemical from from a microorganism that continuously produces the desired protien and introducing it to the patient

Question 5

What is the problem with extracting protiens from a human or animal donor?

Answer 5

Risk of infection
Costly
Could risk an immune response

Question 6

What is recombinant DNA?

Answer 6

DNA that contains DNA from 2 different organisms

Question 7

How is complimentary DNA produced using reverse transcriptase?

Answer 7

-mRNA is extracted from cells with the desired gene
-mRNA acts as a template to make a single stranded copy of complimentary cDNA using reverse transcriptase
-Free DNA nucleotides form hydrogen bonds with the cDNA
-DNA polymerase joins the new nucleotides together using forming phosphodiester bonds forming double stranded DNA
-A copy of the desired gene is transferred to the host cell

Question 8

What does reverse transcriptase do?

Answer 8

Makes DNA from mRNA

Question 9

What are the advantages of reverse transcriptase?

Answer 9

mRNA is used to make a copy of the gene which does not contain introns

Question 10

What enzymes cuts DNA into fragments?

Answer 10

restriction enzymes

Question 11

How do restriction enzymes cut DNA into fragments?

Answer 11

Cuts the sugarphosphate of the DNA at a recognition sequence creating sticky ends

Question 12

What does a gene machine do?

Answer 12

-determines the amino acid sequences of a protein
-mRNA codons for each amino acid are looked up then the complimentay DNA triplets are determined
-the sequence of nucleotide bases is fed into the computer
-nucleotides are joined by the gene machine to make a gene
-Gene with errors are rejected
-PCR is used to multiple the number of genes

Question 13

What is the advantage of creating the gene in a gene machine from the amino acid sequence?

Answer 13

The gene will not contain any introns
faster to use the gene machine than reverse transcriptase(fewer enzyme catalysed reactions)

Question 14

What is a vector?

Answer 14

Used to carry a gene from one organism to another

Question 15

What are the 2 ways DNA can be amplified?

Answer 15

-PCR polymerase chain reaction (in vivo)
-Culture of transformed cells (in vitro)

Question 16

How is a DNA fragment inserted into a vector?

Answer 16

-The same restriction enzymes is used to cut the gene from the DNA and the bacterial plasmid (vector)
-This produces sticky ends with a complimentary base sequence which forms hydrogen bonds with eachother
-The sugar phosphate backbone is joined by enzymes ligase though condensation to form recombinant DNA

Question 17

What is the process by which recombinant DNA is inserted into the host cell?

Answer 17

Transformation

Question 18

How is the host cells membrane made more permeable for transformation?

Answer 18

-Using calcium ions
-Increasing temperature
-Electrical shocks

Question 19

How are microorganisms transformed?

Answer 19

Isolation of gene using restriction enzymes/reverse transcriptase/gene machine
-Cut plasmid with same restriction enzyme
-Sticky ends join by complimentary base pairing
-DNA ligase used to join fragments
-Electric shock to helpcell uptake vector
-Gene markers used to identify cells with recombinant DNA
-Bacteria containing gene grown - protien extracted an purified

Question 20

How are plants transformed

Answer 20

-Isolation of gene using restriction enzymes/ reverse transcriptase/gene machine
-Cut plasmid with same restriction enzyme
-joins sticky ends by complimentary base pairing
-DNA ligase used to join fragments
-Plasmid added to bacterium
-Bacterium added to vector to get gene into plant
-if correct promotor region added with gene then cells will be able to make desired proteins