Final Exam 3

Question 1

Basics of Transformation

Answer 1

• does not require cell to cell contact
  1. Uptakes DNA from surrounding environment
  2. Integrates DNA into genome

Question 2

What does it mean to be competent or have competence

Answer 2

Uptake

Question 3

What are the two types of transformation

Answer 3

1. Natural
   - 400+ bacteria
   - 10-20% of B.Subtilis are competent
   but only 0.1-1% actually can uptake (1-2h)
   -Strep. Pneumonia 100% uptake (5min)
   -uptake dna from external environment
2. Artificial
   - induced
   - electrical or chemical competence

Question 4

What kind of transformation does ARCHAEA do?

Answer 4

Natural

Question 5

What kind of transformation does E.Coli do?

Answer 5

Artificial

Question 6

Specific Sequence DNA

Answer 6

• requires a specific sequence, if there is none, it won’t up take DNA

ADVANTAGE
- wont take up phage or TE that can be detrimental

DISADVANTAGE
- inbreeding

Question 7

Non-Specific Sequence DNA

Answer 7

• will uptake DNA
• ALL G+ are non-specific

ADVANTAGE
- genomic variety

Question 8

How fast is conjugation?

Answer 8

800-1000 nts/second

Question 9

How fast is Transformation?

Answer 9

50-200 nts/second

Question 10

Model for DNA Transformation

Answer 10

1. Needs to have DNA binding ability
2. Fragmentation
3. DNA Uptake
4. Recombination

Question 11

3 Sources of External DNA

Answer 11

1. Cell Lysis
2. Hydrolyse of non-competent
3. Active DNA Secretion

Question 12

What processes the DNA when it is in the channel?

Answer 12

Nuclease

• at this point it is not reversible
• it changes ds –> ss
• the new ss is the competent strain

Question 13

What is heteroduplex

Answer 13

One strand of donor

One strand of recipient