L8_Bacterial Genetics

Question 1

Describe the number of genes, ploidy, chromosome(s), and extrachromosomal DNA of bacteria

Answer 1

~4000 genes, haploid, one circulate dsDNA chromosome, circular plasmids and phage particles

Question 2

Is phage DNA or plasmids essential to bacteria?

Answer 2

No

Question 3

Phage and Plasmids code for virulence factors in many bacteria, name a few examples.

Answer 3

Enterotoxin (E. Coli and V. Cholera)
Exofoliatin (S. Aureus)
Erythrogenic Toxin (S. Pyogenes)
Neurotoxin (C. Tetani)

Question 4

Is there post-translational regulation and or RNA splicing in bacteria?

Answer 4

NO

Question 5

Describe the difference between eukaryotic and prokaryotic gene regulatory elements.

Answer 5

Each eukaryotic gene has its own promoter and regulatory elements, whereas prokaryotic genes of similar function are usually grouped together and regulated by a single promoter and regulatory elements (operon)

Question 6

Describe the difference in the type of regulatory elements that effect gene transcription in eukaryotes and prokaryotes.

Answer 6

In eukaryotes genes are regulated by multiple coordinated transcription factors where as in prokaryotes genes are often directly regulated by metabolic products or deficiencies. (multiple transcription factors vs operator/repressor system)

Question 7

What is special about the 16S RNA gene in bacteria?

Answer 7

It is unique between each species of bacteria but is flanked by highly conserved regions allowing it to be sequenced in order to ID species. (Future of bacterial diagnosis)

Question 8

What are the 3 major factors that regulate gene expression in bacteria

Answer 8

nutritional status, cell-surface sensing, Quorum Sensing

Question 9

What are the three main types of exchange of genetic information between bacteria?

Answer 9

Transformation, transduction, conjugation

Question 10

How do bacteria recognize foreign DNA and degrade it?

Answer 10

They methylate their own DNA so they can recognize it and they degrade foreign DNA with different methylation patterns. This is why genetic exchange is rare overall.

Question 11

What is the symbol to designate a male bacteria with the F gene integrated into the chromosome?

Answer 11

HFr

Question 12

What are the two types of Transduction?

Answer 12

Generalized and Specialized

Question 13

What is an R factor

Answer 13

A segment of non-chromosomal DNA that carries gene(s) for antibiotic resistance. (Large ones are called F-factors and generally carry resistance to multiple antibiotics)

Question 14

Is phage bacteria extrachromosomal or integrated?

Answer 14

Can be either

Question 15

Why is genetic exchange relatively rare in bacteria?

Answer 15

Do to gene modification, mainly methylation, each bacteria has its only signal of “self”, foreign DNA is usually cleaved by restriction enzymes

Question 16

What type of bacteria have a higher frequency of genetic exchange, gram pos or gram neg?

Answer 16

Gram Negs like to get it on

Question 17

Describe generalized transduction

Answer 17

Lytic phages can infect bacteria and cause lysis-this can release DNA which can be taken up by the bacteriophage and carried to another bacterium

Question 18

Describe Specialized transduction

Answer 18

Lysogenic phages can insert themselves into the bacterial chromosome and later can excise themselves along with some adjacent bacterial DNA which can be carried to a new bacterium (transfer of toxins)

Question 19

to pathogenicity islands have intrinsic relocation mechanisms?

Answer 19

no

Question 20

What type of sequences do restriction enzymes typically recognize?

Answer 20

Palindromic