Chapter 8 Bacterial Genetics

Question 1

Define the terms
mutation, horizontal gene transfer, genotype, phenotype, auxotroph and prototroph

Answer 1

• Mutation: changes in existing nucleotide sequence
• Horizontal gene transfer: movement of DNA from one organism to another ‘friend’
• Genotype:
• Phenotype:
• Auxotroph
• Prototroph

Question 2

Describe three outcomes of base substitutions

Answer 2

1. Single Base Substitution

Question 3

Describe the consequences of removing or adding nucleotides

Question 4

Explain how transposons cause mutations

Question 5

Describe the three general groups of chemical mutagens

Question 6

Explain why transposons induce mutations

Question 7

Explain how X-rays and UV light damage DNA

Question 8

Explain how errors in nucleotide incorporation by DNA polymerase can be repaired, and the role of methylation in the process

Question 9

Explain how modified nucleobases can be repaired

Question 10

Describe three mechanisms cells used to repair thymine dimers

Question 11

Compare and contrast direct and indirect selection

Question 12

Describe how direct selection is used to screen for possible carcinogens

Question 13

Describe the process of DNA-mediated transformation, including the role of competent cells

Question 14

Describe generalized transduction

Question 15

Compare and contrast conjugation involving the following donor cells: F+, Hfr, and F’