Genetics

Question 1

What is DNA?

Answer 1

DNA (deoxyribonucleic acid) is a moleq that carries genetic information, important for all cellular functions.

Question 2

How does transcription work?

Answer 2

1. The region of DNA carrying the gene unwinds and unzips and 2 DNA strands are separated.
2. One of the DNA strands (template) is used to form mRNA.
3. mRNA leaves the nucleus through the nuclear pore.

Question 3

How does translation work?

Answer 3

1. mRNA attaches to a ribosome.
2. Ribosome translates the message in mRNA into a seq of AA joined together by polypeptide bonds to form a polypeptide.
3. As the ribosome moves along the mRNA, the polypeptide produced gets longer as more AA are joined together.
4. At the end of the mRNA, the ribosome detaches from the mRNA, polypeptide is released.

Question 4

What are the advantages of bacteria produced human insulin?

Answer 4

Does not induce allergic responses in patient
Easier and cheaper to produce in large quantities
Less risk of contamination by disease causing organisms
Ethical concerns of vegetarians/religious groups overcome.

Question 5

Describe the structure of the DNA moleq.

Answer 5

DNA has a double helix structure, with 2 strands. They are held together by complementary base pairs. The basic units of DNA are nucleotides. A nucleotide is made up of a deoxyribose sugar, phosphate group and base. The bases are held together by hydrogen bonds, and A pairs with T and C pairs with G

Question 6

What are the first 2 steps of genetic engineering?

Answer 6

Obtain the segment of DNA in human chromosomes that code for the human insulin gene. Cut the gene using the restriction enzyme. This enzyme cuts the restriction site at 2 ends to produce sticky ends. These bases can pair with complementary bases to form a double strand. Each sticky end is a single strand sequence of DNA bases that can pair with complementary bases to form a double strand.
Obtain a plasmid from a bacterium. Cut the plasmid with the same restriction enzyme. This produces sticky ends complementary to the ends of the insulin gene.

Question 7

What is the third step in GE?

Answer 7

Mix the plasmid with the DNA fragment containing the human insulin gene. The human insulin gene will bind to the plasmid by complementary base pairing between their sticky ends. Add the enzyme DNA ligase to seal the human insulin gene to the plasmid. This plasmid containing DNA from 2 diff organisms is the recombinant plasmid

Question 8

What are the 4th and 5th steps in GE?

Answer 8

Mix the recombinant plasmid with Escherichia Coli bacterium. Apply temporary heat/electric shock. This opens up pores in the cell surface membrane of the bacterium for the plasmid to enter.
This transgenic bacterium will use the new gene to make insulin. Such bacteria can be isolated and grown for mass production of human insulin. The insulin protein has to be extracted and purified before it can be used.

Question 9

What are the benefits of GE?

Answer 9

Low cost production of medicines
Production of crops that grow in extreme conditions
Development of pest/pesticide resistant crop
Development of food designed to reach nutritional goals.

Question 10

What are the social and ethical issues of GE?

Answer 10

1. New proteins in GM food might cause allergies in humans that consume them.
2. GM food may prove to be toxic or cancer causing to people that consume them.
3. The resulting deaths of useful insects may result in biodiversity loss
4. Some biotech companies engineer crop plants to produce seeds that produce seeds that cannot germinate- farmers have to buy new seeds every year.
5. Objections to consuming animal gene in plants.
6. Morally wrong to exploit animals for medical research
7. Deliberately create new combinations of genes to use in chem/bio warfare.
8. There is a concern that antibiotic resistant bacterium will be incorporated into bacteria.
9. May lead to class distinctions so only individuals with suff financial means acn afford GE.