Genetics.

1.    How does cDNA differ from the genomic coding sequence?

2.     What is the natural function of bacterial restriction endonucleases? How might the presence of restriction enzymes affect the use of bacteria as hosts for carrying cloned genes?

3.    Gel electrophoresis analysis of a PCR reaction generated with a pair of oligonucleotide primers showed several fragments instead of the expected single fragment. Give three possible explanations for this result.

4.    Is it possible to covalently join blunt ends?

5.    What are the consequences of the infection of a plant with Agrobacterium?

6.    Why does regulation of the lac operon require that the lacO operator either overlaps or is adjacent to the promoter of the structural genes?

7.    When E. coli cells are growing in the presence of lactose, is the level of cAMP high or low?

8.    In regard to mating-type interconversion in yeast, what phenotype would you expect from type a cell that has a deletion of the HMR cassette?

9.      In eukaryotes, some enhancers are located many kilobases away from the genes they regulate. By what means can these remote enhancers stimulate transcription of the genes?

10. What is the advantage of the clustering of bacterial genes, which belong to a common metabolic pathway?

11. What is the difference between a missense and a nonsense mutation?

12.  Why are missense mutations less likely to result in proteins lacking normal function than frameshift mutations?

13. What is a base analog and why are some mutagenic?

14. How do the consequences of mutations in germline cells and somatic cells differ?
15. The human genome has about 300,000 copies of a transposon-like repetitive element known as an Alu repeat. These elements have recently been shown to be the source of genetic disease. Describe a mechanism by which Alu elements could cause disease.

16. Describe3 transposition pathways

17. Where Ames test is used? Describe its principle. Define reversion.

18. What is the function of σ factor?

19. Describe mRNA capping

20. Define suppressor mutations.