Module 6.1.3 - Manipulating Genomes

Question 1

What is a genome?

Answer 1

Minimum quantity of genetic material that contains 1 copy of all genes of an individual or of a population or a species

Question 2

What is genomics?

Answer 2

Study of whole set of genetic info in form of DNA base sequence in cells of organism

Question 3

What is gene technology?

Answer 3

Manipulation of organism’s DNA to produce an organism or product that can be used in some way

Question 4

What are autosome?

Answer 4

Chromosomes that arent sex related

Question 5

What are terminator bases?

Answer 5

Can be any base, modified bases that stop the chain

Question 6

What is the sanger method?

Answer 6

• based on premature ending of DNA synthesis
• if modified nucleotides are used during DNA synthesis, process can be halted
• DNA being sequenced
• mix of normal nucleotides and 1 type of terminator nucleotide
• primer starts it off
• DNA polymerase

Question 7

What is gel electrophoresis?

Answer 7

• separates different lengths of DNA
• phosphate in backbone of DNA is negatively charged
• DNA placed at top
• electric current applied over it
• ager resists movement of DNA fragments
• DNA moves towards positive electrode
• DNA moves at different rates
• longer sequences dont move as far/near top
• shorter sequences move further towards bottom

Question 8

What does PCR stand for?

Answer 8

Polymerase chain reaction

Question 9

What are the steps of PCR?

Answer 9

1. DNA is denatured to separate into 2 separate DNA strands, heat DNA to 95 degrees
2. add 2 primers to 2 separated DNA strands, temp is cooled to 55 degrees to help primers bind to DNA, primer is an attachment that signals to a polymerase where to start synthesising new DNA, primers bond with hydrogen bonds
3. extension of DNA, 2 polymerase molecules attach to 2 primers on DNA strands and move along strand, create new ‘complementary’ DNA as move along, temp goes up to 72 degrees

Question 10

What is genetic engineering?

Answer 10

Using techniques to genetically modify DNA by combining DNA from different organisms to produce recombinant DNA
- genes are isolated from 1 organism and inserted into another organism, using a vector

Question 11

What is the process of genetic engineering?

Answer 11

• require gene isolated
• copy of gene places inside vector
• vector carries gene to recipient cell
  -recipient expresses the novel gene

Question 12

What are the 2 ways of isolating a gene?

Answer 12

1. • extract mRNA from cells to show what genes are being expressed
     - reverse transcriptase copies mRNA back to DNA and product is complementary DNA or cDNA
     - cDNA can then be copied into double stranded DNA which codes for original protein
2. • restriction endonuclease used to cut out gene from DNA
     - cut is staggered, leaving some bases unpaired
     - ‘sticky ends’ make it easier to insert gene into DNA of recipient organism

Question 13

What are the 3 ways of getting a vector into a recipient cell?

Answer 13

1. Heat shock - alternate temp from cold to warm (0 degrees-42 degrees) in presences of calcium chloride which allows membrane of host cells to become more porous
   - calcium ions, Ca2+, surround DNA- and allows entry through phospholipid bilayer and foreign DNA enters cell
   - doesn’t cause all DNA to be in plasmid
2. electrofusion - electrical fields help to introduce DNA into cells
3. T1 (recombinant) plasmids - are inserted into bacterium Agrobacterium tumefaciens, which infects some plants and naturally inserts its genome into host cell genome

Question 14

What is the process of inserting a gene into a cell using a plasmid?

Answer 14

1. chromosomal DNA of organism A
2. PCR amplifies gene of interest
3. multiple copies of single gene from organism A
4. insertion of gene into bacterial plasmid using ligase
5. plasmid with gene from organism A
6. insertion of plasmid into organism B

Question 15

What is DNA profiling?

Answer 15

• extract DNA from sample using PCR
• digest sample, DNA cut to small fragments with restriction endonuclease
• separate DNA fragments using electrophoresis

Question 16

What are a variable number tandem repeat (VNTR)?

Answer 16

Introns, centromeres and telomeres have short sequences of DNA that are repeated many times