molecular genetics

Question 1

what is nucleotide made up of

Answer 1

-sugar
-phosphate group
-nitrogenous base

Question 2

gene

Answer 2

a sequence of DNA nucleotide that controls the formation of a single polypeptide. it is also a unit of inheritance

Question 3

describe DNA

Answer 3

-nucleotide consists of sugar backbone, phosphate group and nitrogenous base

-DNA is made up of many DNA nucleotides, ATGC complementary base pairing in a 1:1 ratio by hydrogen bonds

-two strands of nucleotide that are antiparallel are twisted to form double helix structure

-it coils tightly around histone proteins to form chromosomes

Question 4

what are the different nitrogenous base

Answer 4

-adenine
-cytosine
-guanine
-thymine

Question 5

how is a polypeptide/protein made

Answer 5

1. message in the gene is copied into mRNA
2. mRNA travels from nucleus to the cytoplasm and attaches itself to a ribosome
3. ribosome moves along the mRNA, synthesising a polypeptide. polypeptide is released when ribosome leaves mRNA

Question 6

genetic engineering of insulin [process]

Answer 6

1. [cut] obtain fragment of DNA in human chromosome that contains insulin gene. each side of gene has a restriction site. using restriction enzyme, it will cut at the restriction site to produce sticky ends
2. [cut] obtain plasmid from bacteria. cut plasmid with the same restriction enzyme to produce sticky ends that are complementary to the ends of insulin gene
3. [ligase] mix plasmid with DNA fragment. insulin gene will bind to plasmid by complementary base pairing between their sticky ends
4. [seal] add DNA ligase (enzyme) to seal human insulin gene to the plasmid. this forms a recombinant plasmid (contain DNA from 2 diff organisms)
5. [put back] mix recombinant plasmid with Escherichia coli (E.coli) bacterium. apply temporary heat/shock to open up pores in cell membrane of bacterium for plasmid to enter
6. transgenic bacterium formed, will use new gene to make insulin. can be isolated and grown in a fermenter for mass production. must be extracted and purified before use

Question 7

benefits of genetic engineering for insulin production

Answer 7

-does not induce allergy response; insulin produced is identical to human insulin

-less risk of contamination by disease causing microorganisms; compare to obtaining from pancreas of animals

-easier and cheaper to produce in large quantities; bacteria reproduces rapidly

-overcome ethical concerns; vegetarians object use of insulin from animals

Question 8

positive social impacts of genetic engineering

Answer 8

-low production cost [use bacteria] -> affordable -> accessible to more

-promote interest and investment in science education -> more scientifically literate society

-develop food designed to meet specific nutritional goals -> healthier

-develop crops that produce toxins that kills pests and pesticide-resistant crops/grows in extreme weather conditions [drought, salt tolerant] -> farmers wont suffer from losses

Question 9

negative social impacts of genetic engineering

Answer 9

-long term health implications
-ecological problem, probability of causing imbalance

Question 10

negative ethical impacts of genetic engineering

Answer 10

-welfare of animals, pain and distress
-technology accessible to richer companies -> serious to poorer society as they struggle to earn a living