topic 4

Question 1

what are animals selectively bred for

Answer 1

to produce more milk and meat

Question 2

what are crops selectively bred for

Answer 2

disease resistance

Question 3

what are dogs selectively bred for

Answer 3

good gentle temprament

Question 4

what are plants selectively bred for

Answer 4

to produce bigger fruit

Question 5

how is selective breeding done

Answer 5

1. from your existing stock, select the ones which the characteristics you’re after
2. breed them with each other
3. select the best of the offspring and breed them together
4. continue this process over several generations so the trait will be stronger and stronger.

Question 6

disadvantages of selective breeding

Answer 6

• reduces gene pool
• inbreeding can cause health problems
• lack of variation, susceptible to diseases

Question 7

how can vectors be used to insert DNA into other organisms

Answer 7

1. the DNA you want to insert and the vector DNA is cut out with a restriction enzyme.
2. the vector DNA and the DNA you’re inserting are left with sticky ends.
3. the ligase enzymes join the pieces of DNA to make recombinant DNA.
4. the recombinant DNA is now inserted into other cells