Quiz 1 - Mulvey - Bacterial Genetics

Question 1

What is a regulon?

Answer 1

A group of genes that are coordinately regulated.

*Regged by a single transcription factor or regulator

Question 2

What do sigma factors recognize and do?

Answer 2

Specific promoter sequences, or specific elements. Recruit polymerase

Direct the RNA polymerase complex where to bind w/in DNA

*Bacteria contain numerous sigma factors that mediate responses to stressors

Question 3

How do bacteria change their genetic makeup?

Answer 3

Mutation

HGT (Horizontal Gene Transfer)

Question 4

What are the 3 types of HGT?

Answer 4

Transformation

Transduction

Conjugation

Question 5

What is transformation?

Answer 5

Bacteria taking up DNA from the environment

*These bacteria are called “competent”

**Some bacteria take up DNA only from the same genus

***Most naturally competent bacteria take up linear DNA, not circular

Question 6

What is transduction?

Answer 6

Transfer of DNA by viruses or bacteriophage (10^31 phages on earth)

*General - Any portion of DNA

**Specific - Specific portion of DNA

Question 7

What is the phage life cycle?

Answer 7

Lytic and lysogenic

Question 8

What is prophage?

Answer 8

Carry important fitness and virulence determinants

Question 9

What is conjugation?

Answer 9

Bacterial sex

*F plasmid connects two bacteria, DNA is shared, now both cells have the F plasmid

Question 10

What are virulence plasmids?

Answer 10

Encode for virulence factors, and can convert a bacterium into a pathogen

Question 11

What are resistance (R) plasmids?

Answer 11

Contain genes that provide resistance against antibiotics or poisons.

Question 12

What are transposable elements (transposons)

Answer 12

DNA elements that move from one place in bacterial DNA to another

Question 13

T/F - Bacteria have an open reading frame.

Answer 13

True - It’s called a cistron or polycistronic region (operons with multiple genes driven by a single promoter)

Question 14

T/F - Diphtheria toxin is regulated by a regulator called DtxR.

Answer 14

True

*The pathogen can sense that its in a host due to the lack of Fe2+ available, and then this turns on

Question 15

T/F - Transcription and translation are coupled in bacteria.

Answer 15

True

Question 16

When an F factor becomes integrated into the chromosome of an F cell, what occurs?

Answer 16

It makes that cell a high frequency of recombination cell, or an Hfr cell

Question 17

When an Hfr donor passes a portion of its chromosome into an F- recipient, what results?

Answer 17

A recombinant F- cell results

Question 18

T/F - A single plasmid can carry the genes to resist many different antibiotics.

Answer 18

TRUE