L8_Bacterial Genetics Flashcards

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1
Q

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

A

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

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2
Q

Is phage DNA or plasmids essential to bacteria?

A

No

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3
Q

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

A

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

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4
Q

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

A

NO

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5
Q

Describe the difference between eukaryotic and prokaryotic gene regulatory elements.

A

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)

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6
Q

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

A

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)

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7
Q

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

A

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)

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8
Q

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

A

nutritional status, cell-surface sensing, Quorum Sensing

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9
Q

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

A

Transformation, transduction, conjugation

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10
Q

How do bacteria recognize foreign DNA and degrade it?

A

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.

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11
Q

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

A

HFr

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12
Q

What are the two types of Transduction?

A

Generalized and Specialized

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13
Q

What is an R factor

A

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)

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14
Q

Is phage bacteria extrachromosomal or integrated?

A

Can be either

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15
Q

Why is genetic exchange relatively rare in bacteria?

A

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

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16
Q

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

A

Gram Negs like to get it on

17
Q

Describe generalized transduction

A

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

18
Q

Describe Specialized transduction

A

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)

19
Q

to pathogenicity islands have intrinsic relocation mechanisms?

A

no

20
Q

What type of sequences do restriction enzymes typically recognize?

A

Palindromic