Modern Genetics: Gene Technology

Question 1

Use of gene therapy

Answer 1

Potential treatment for genetic diseases involving altering the genotype

Question 2

2 ways of gene therapy

Answer 2

Replacing- defective gene with a normal allele
Supplementing- the gene by adding copies of the normal allele which must be dominant to mask the effects of the recessive defective allele

Question 3

Types of gene therapy: germ line therapy

Answer 3

Altering sperm or egg cells before fertilisation

Question 4

Types of gene therapy: somatic cell therapy

Answer 4

Every cell in the body contains defective allele but only affected area is targeted

Question 5

Types of gene therapy: somatic cell therapy what will carry normal alleles to target cells?

Answer 5

A vector

Question 6

Liposomes as vectors: what are they?

Answer 6

Lipid spheres which can fuse with phospholipid bilateral and release contents

Question 7

Liposomes as vectors: method

Answer 7

Recombinant DNA is used to insert the healthy gene into a plasmid which is then wrapped in a liposome
The gene is released into the cell and moves to the nucleus

Question 8

Liposomes as vectors: successful?

Answer 8

Low success of DNA being transcribed

Question 9

Viruses as vectors

Answer 9

Virus genetic material removed and desired gene added to viral genome
Virus enters the cell and gene is transported to the nucleus

Question 10

Viruses as vectors successful?

Answer 10

Relying on the viral antigens being able to grant access into the cell

Question 11

Using plasmids as vectors: once the gene for the desired protein has been identified:

Answer 11

1. Multiple copies of desired gene produced
2. Gene inserted into a vector and transferred into host cells
3. Host cells that have successfully taken up the gene are identified using a marker
4. Host cells allowed to multiple or cloned

Question 12

Using plasmids as vectors the process:

Answer 12

1. Restriction enzymes cuts gene and plasmid= complementary sticky ends
2. Ligase- sugar phosphate backbone
3. New gene inserted between 2 marker genes eg anti biotic resistance
4. Bacteria and plasmids mixed some taken up by biological conjugation
5. Cultures on agar plates containing ampicillin- any with plasmid will resist and grow
6. Small samples then grown on tetracycline- if desired genes not grow as this resistant gene oils have been interrupted by inserted gene
7. Grown on a large scale

Question 13

Summary of the process of using plasmids as vectors

Answer 13

2 markers- 1 shows plasmids taken up and other shows it has been disrupted by inserted gene

Question 14

Process of producing DNA fragments to insert into plasmids using reverse transcriptase

Answer 14

• mature mRNA if desired gene made into DNA:
  Reverse transcriptase and free DNA nucleotides= synthesis of a single strand of DNA complementary to template mRNA
  Enzyme breaks down mRNA strand leaving single strand of DNA
  DNA polymerase adds complementary strand= double strand of original dna without introns inserted into plasmid

Question 15

Inserting genes into animal and plant cells

Answer 15

Gene gun
Liposomes: gene wrapped in liposomes (spheres formed of a lipid bilateral fuse with cell membrane)
Micro injection- DNA injected- most successful

Question 16

Knockout organisms

Answer 16

Has a certain gene inscribed and cannot be transcribed

Question 17

Transgenic plants

Answer 17

Insert desired gene into plasmid- insert in plant cell- culture- plant that produces desired protein that can be extracted

Question 18

Why do plant cells retain?

Answer 18

Totipotency

Question 19

Cloning plants

Answer 19

Block of tissue removed

Cultured with auxin and cytokinins