Genetic elements of the cell
Answers are for parents and teachers.
1
What are transposons and how do they affect heredity?
DNA pieces that change position in the genome; if inserted into a gene they switch it off or alter its activity, so they are a source of hereditary variation.
2
Why is taking antibiotics on your own risky?
They select resistant strains, which multiply; resistance spreads quickly via plasmids. Take antibiotics only as prescribed by a doctor and complete the course.
3
Write the four results of Griffith’s experiment as a table.
Live S – dies; live R – lives; dead S – lives; dead S + live R – dies.
4
How do the lytic cycle and lysogeny of a phage differ?
In the lytic cycle the phage multiplies and destroys the bacterium; in lysogeny the phage DNA stays in the bacterial chromosome as a prophage and divides with the cell.
5
A bacterium divides every 20 minutes. How many will one give in 3 hours? (Number only.)
512