Topic 4d - Gene regulation & biotech

Question 1

What is an operon and where is it found?

Answer 1

functional unit of control & gene expression in prokaryotes

Question 2

Gene regulation in eukaryotes…

Answer 2

1. frequency/rate of transcription (nucleus)
2. mRNA processing (nucleus)
3. stability & rate of translation (cytoplasm)
4. modification of proteins for functionality (cytoplasm)
5. rate of protein degradation (cytoplasm)

Question 3

What is PCR?

Answer 3

Polymerase chain reaction - amplifies small pieces of DNA. Reproduces DNA molecules in several minutes ie. 1 molecule -> 1 billion copies in several hours

Question 4

Phases of one PCR cycle…

Answer 4

1. Heating to separate DNA strands (90deg C)
2. Cooling (50 deg C) allows primers & DNA polymerase to bind
3. New DNA strands synthesised (70deg C)

Question 5

T or F - for every PCR cycle, DNA copies double

Answer 5

true

Question 6

What is a reverse transcriptase PCR used for?

Answer 6

detecting mRNA

Question 7

What is a real time PCR used for?

Answer 7

quantifying DNA or mRNA

Question 8

Next generation of sequencing…?

Answer 8

high throughput screening

Question 9

Creating genetically modified (GM) crops…

Answer 9

1. Isolate gene of interest from organism & synthesise if sequence is known
2. Insert gene into crop genome using plasmid Agrobacterium tumifaciens

Question 10

Creating GM crops in more detail…

Answer 10

1. DNA containing Bt gene & Ti plasmid cut with same restriction enzyme
2. Bt genes & Ti plasmids now have same ‘sticky ends’ & DNA ligase bonds Bt gene into plasmids
3. Bacteria (Agrobacterium tumifaciens) are transformed with recombinant plasmids
4. Transgenic bacteria enter plant cells & Bt genes are inserted into chromosomes of plant cells