Chapter 9

Question 1

conjugation

Answer 1

takes place when genetic material passes directly from one bacterium to another

Question 2

transformation

Answer 2

when a bacterium takes up DNA from the medium in which it is growing

Question 3

transduction

Answer 3

takes place when bacterial viruses carry DNA from one bacterium to another
- bacterial genes incorporated into phage coats and transferred to other bacteria by phased

Question 4

which process of DNA transfer in bacteria requires a virus?

Answer 4

transduction

Question 5

what did lederberg and Tatum demonstrate?

Answer 5

that bacteria can transfer and recombine genetic information

Question 6

cells that can take up DNA through their cell membranes are said to be

Answer 6

competent

Question 7

What does cotransformation and relative rates

Answer 7

the higher the rate of cotransformation, the closer the genes are on the bacterial chromosome

Question 8

horizontal gene transfer

Answer 8

genes can be passed between individual members of different species by nonreproductive mecahnsims

Question 9

restriction-modification systems

Answer 9

bacteria produce enzymes called restriction endonucleases that recognize and cleave double stranded DNA at specific nucleotide sequences

Question 10

CRISPR-CAS systems

Answer 10

combine small RNA molecules known as CRISPR RNA with CAS proteins to provide defense against specific foreign DNA molecules originating from viruses,

Question 11

what do the CRISPR-cas systems contain

Answer 11

1. DNA sequence called CRISPR array
2. set of genes encoding proteins

Question 12

CRISPR array

Answer 12

• located in bacterial/archaeal chromosome and consists of a series of repeated DNA sequences called clustered regularly interspaced short palindromic repeats

Question 13

palindromic sequences

Answer 13

sequences that read the sequences that read the same forward and backward on two complementary DNA STARANDS

Question 14

CAS proteins

Answer 14

essential to functioning CRISPR-Cas systems

Question 15

How does CRISPR-cas system function

Answer 15

Adaptation- when foreign DNA from a virus, plasmid or other element enters the cell
- foreign DNA is identified and cleaved by Cas proteins into protospacers
- protospacers are then processed into CRISPR array as spacers which serve as a memory of foreign DNA

Question 16

second stage of CRISP

Answer 16

• CRISPR array is transcribed into a long CRISPR precursor RNA and cleaved by cas proteins and processed into crna’s
• combines with a CAS PROTEIN TO FORM AN EFFECTOR COMPLEX

Question 17

what happens in the final stage of CRISPR

Answer 17

interference- foreign DNA from the same plasmid enters cell
- effector complex binds to foreign DNA through base pairing between cRNA and foreign DNA sequences
- cas protein cleaves foreign DNA which is degraded

Question 17

oncogenes

Answer 17

may stimulate cell division and cause the formation of tumors