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Bacte LEC > BACTERIAL GENETICS > Flashcards

BACTERIAL GENETICS Flashcards

1
Q

single, long piece of circular, double-stranded DNA

Contain 2000 to 4000 genes.

A

Chromosome

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2
Q

Small DNA circles
Replicate independently

A

Plasmids

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3
Q

Call for abilities they are not born with (ability to resist antibiotics, toxins, ability to produce sex pilus) - some bacteria may acquire this from other organisms.

Genes for toxins, proteins that promote transfer

A

Plasmids

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4
Q

Genetic transfer

A

Vertical gene transfer
Horizontal gene transfer

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5
Q

Mother cell to offspring
Binary fission

A

Vertical Gene Transfer

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6
Q

From one bacterial cell to another bacterial cell

Conjugation
Transformation
Transduction

A

Horizontal Gene Transfer

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7
Q

• Bacterial mating
• Enteric, gram (-) bacteria

A

CONJUGATION

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8
Q

The F+ male has a plasmid that calls for the codes for the production of the sex pilus

It can serve as the genetic donor

Sex pilus adheres to an F- (female)

One strand of the plasmid is transferred onto the female

They are now both able to copy it - 2 copies of the strand

The female has become F+ or a male bacterium, and it is now able to code for a sex pilus.

A

CONJUGATION

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9
Q

The plasmid being shared is an R plasmid

Plasmid that can help bacteria resist some forms of antibiotic

A

Resistance Plasmid Conjugation

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10
Q

F+ r positive donor donating the R plasmid onto an F-r negative
The recipient now becomes F+ R positive bacterium.

Once it’s shared, it is automatically replicated to produce two strands, and the recipient who was previously R-(non-resistant) and F- unable to produce sex pilus can now produce six pilus.

A

Resistance Plasmid Conjugation

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11
Q

• A recombinase functioning in recombinational DNA repair in bacteria

A

RecA Protein

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12
Q

occurs after the uptake of DNA fragments from the environment

When a bacterium dies, it breaks up into pieces, and some of its genetic material may be free swimming in the environment

A

TRANSFORMATION

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13
Q

as a process of Gene transfer may occur between two different species

This process of gene transfer will occur
ONLY to a competent bacteria

A

Transformation

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14
Q

are able to accept naked DNA from the environment.
These possess the RecA protein
- which is a critical enzyme in the process of transformation

A

Competent bacteria

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15
Q

The_____ catalyzes the pairing of the single stranded
DNA with the complementary regions of the double-stranded
DNA

A

RecA protein

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16
Q

Transfer of DNA Fragments from one bacterium to another by a bacteriophage

A

TRANSDUCTION

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17
Q

are viruses that kills bacteria

A

Bacteriophages

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18
Q

“Carry-across”

A

Transduction

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19
Q

TYPES OF BACTERIOPHAGE THAT INITIATE
TRANSDUCTION

A

• Lytic or Virulent phage

• Temperate phage

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20
Q

• Involves the production of viruses using a host cell to manufacture more viruses, and then the viruses would burst out of the host bacterium -> hence the name_____

A

Lytic or Virulent phage

virulent

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21
Q

Replicate through the Lytic cycle

A

Lytic or Virulent phage
• T-phages

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22
Q

• Undergoes replication through the lysogenic cycle

A

Temperate phage

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23
Q

Involves the incorporation of the viral genome into the host cell genome creating the prophage

A

Temperate phage

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24
Q

Temperate phage

Virions will now contain the_____. It has both the genetic material of the temperate phage and the bacterial host (mixture of genes)

A

prophage

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25
Q

TWO FORMS OF TRANSDUCTION

A

GENERALIZED TRANSDUCTION

SPECIALIZED TRANSDUCTION

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26
Q

• During assembly, a genetic material is encased in a capsin.

It infects another bacteria, but the genetic material it releases is that of the first bacterial host

• The bacterium now has gained genetic material from another bacterial host.

A

GENERALIZED TRANSDUCTION

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27
Q

When the lytic phages replicate, the capsid sometimes assembles around a small fragment of the bacterial DNA that’s not viral by nature

• It appears to be a virus / bacteriophage, but it carries it a bacterial DNA so it causes the transfer of one of the genetic material of another bacteria onto another bacterium

A

GENERALIZED TRANSDUCTION

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28
Q

• Initiated by the temperate phage which undergoes the Lysogenic cycle as it replicates

• The bacterial organism that falls prey to this type of Gene transfer undergoes lysogenic conversion

A

SPECIALIZED TRANSDUCTION

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29
Q

Some bacterial DNA becomes part of the phage genome; Some phage DNA remains in the bacterial genome.

A

SPECIALIZED TRANSDUCTION

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30
Q

Examples
Corynebacterium diphtheria
Streptococcus pyogenes
Clostridium botulinum
Vibriocholerae

A

Specialized transduction

31
Q

• Cells are immune to reinfection by the same phage

Acquired after bacterial cells under bacterial conversion

• Cells may exhibit new properties

A

LYSOGENIC CONVERSION

32
Q

Allows phage to take a bit of the adjacent bacterial
DNA
•
There’s a prophage formation

When it transfers genetic material onto another bacterial host, it does not just carry viral DNA with it,

Carries bacterial DNA as well -› a combination

A

LYSOGENIC CONVERSION

33
Q

The genetic material may carry a portion of the host and the temperate phage

All its offsprings, the new virions carry a combination of DNA of the bacteria and that of the virus

When it infects another bacteria, the bacteria has access to both phage DNA and bacterial DNA

A

LYSOGENIC CONVERSION

34
Q

any change in the DNA base sequence

Example: when bacterial cells are exposed to radiation

A

Mutation

35
Q

May cause plasmids to integrate into the chromosome
responsible for the spread of antibiotic resistance genes

A

Mobile Genetic Elements

36
Q

: mobile DNA segments (jumping genes)

A

Transposons

37
Q

A bacteria contains ______genes.

A

2000 to 4000

38
Q

T or F

Plasmids

Replicate independently

A

True

39
Q

Call for abilities they are not born with (ability to resist antibiotics, toxins, ability to produce sex pilus) – some bacteria may acquire this from other organisms

A

Plasmids

40
Q

Genes for toxins, proteins that promote transfer

A

Plasmids

41
Q

Types of horizontal gene transfer

A

Transduction
Transformation
Conjugation

42
Q

Conjugation happens in…

A

Enteric, gram (-) bacteria

43
Q

• It causes the host bacterium to die/lyse so the new variants can come out of the host cell

Create virions using the host cell

A

Lytic or Virulent phage

44
Q

Virulent phage

■ T-phages

■ Replicate through the..

A

Lytic cycle

45
Q

Does not kill the host cell immediately, rather slowly_> will infect it first

Release its genetic material and cause it to incorporate or mix with the host cell’s genome.

Once they mix, it is called the prophage.

A

Temperate phage or Phage Lambda

46
Q

Temperate phage

■ Phage lambda

■ Undergoes replication through the…

A

lysogenic cycle

47
Q

Bacteria that undergo specialized transduction

A

Examples
○ Corynebacterium diphtheria
○ Streptococcus pyogenes
○ Clostridium botulinum
○ Vibrio cholerae

48
Q

The bacterial chromosome, also called the____, consists of a single, closed, circular piece of dsDNA that is supercoiled to fit inside the cell.

A

genome

49
Q

It contains all the information needed for cell growth and replication

A

Genome

50
Q

______ are specific DNA sequences that code for the amino acid sequence in one protein (e.g., one gene equals one polypeptide), but this may be sliced up or combined with other polypeptides to form more than one protein.

A

Genes

51
Q

e genetic information encoded in the bacterial chromosome, many bacteria contain extra information on small circular pieces of extrachromosomal, dsDNA called______.

A

plasmids

52
Q

They are not essential for bacterial growth, so they can be gained or lost.

A

Plasmids

53
Q

Genes that code for antimicrobial resistance (and sometimes toxins or other virulence factors) are often located on plasmids.

A

Plasmids

54
Q

Plasmids are located in the______ of the cell and are selfreplicating and passed to daughter cells, similar to chromosomal DNA

A

cytoplasm

55
Q

Plasmids

They also may sometimes be passed (nonsexually) from one bacterial species to another through_______ (horizontal transfer of genetic material by cell-tocell contact).

This is one way drug resistance is acquired.

A

conjugation

56
Q

Mobile Genetic Elements

Certain pieces of DNA are mobile and may jump from one place in the chromosome to another place. These are sometimes referred to as…

A

jumping genes

57
Q

are related mobile elements that contain additional genes.

often carry drug-resistance genes and are usually located in plasmids.

A

Transposons

Transposons

58
Q

______are changes that occur in the DNA code and often result in a change in the coded protein or in the prevention of its synthesis.

Some _____ are silent, where a change in the DNA sequence does not result in the substitution of a different amino acid in the resulting protein

A

Mutations

59
Q

_________is a method by which genes are transferred or exchanged between homologous (similar) regions on two DNA molecules, forming new combinations of genes on a chromosome

A

Genetic recombination

60
Q

This method provides a way for organisms to obtain new combinations of biochemical pathways and adapt to changes in their environment.

A

Genetic recombination

61
Q

is the uptake and incorporation of free or naked DNA into a bacterial cell

A

Transformation

62
Q

Cells that can take up naked DNA are referred to as being______.

A

competent

63
Q

Transformation

Only a few bacterial species, such as (3), do this naturally.

Bacteria can be made competent in the laboratory, and transformation is the main method used to introduce genetically manipulated plasmids into bacteria, such as E. coli, during cloning procedures.

A

Streptococcus pneumoniae, Neisseria gonorrhoeae, and H. influenzae

64
Q

is the transfer of bacterial genes by a bacteriophage from one cell to another

A

Transduction

65
Q

A________ consists of a chromosome (DNA or RNA) surrounded by a protein coat.

When a phage infects a bacterial cell, it injects its genome into the bacterial cell, leaving the protein coat outside.

A

bacteriophage

66
Q

_________, in which the bacteriophage DNA directs the bacterial cell to synthesize phage DNA and phage protein and package it into new phage particles.

The bacterial cell eventually lyses (lytic phase), releasing a new phage that can infect other bacterial cells.

A

lytic pathway

67
Q

In some instances, the phage DNA instead becomes incorporated into the bacterial genome, where it is replicated along with the bacterial chromosomal DNA; this state is known as_______, and the phage is referred to as being_____.

A

lysogeny

temperate

68
Q

During______, genes present in the phage DNA may be expressed by the bacterial cell

An example of this in clinical microbiology is(3) that are lysogenized with a temperate phage carrying the gene for diphtheria toxin cause disease.

Strains lacking the phage do not produce the toxin and do not cause disease. Under certain conditions, a temperate phage can be induced

A

Lysogeny

C. diphtheriae. Strains of C. diphtheriae

69
Q

Strains lacking the phage do not produce the toxin and do not cause disease.

Under certain conditions, a _____can be induced, the phage DNA is excised from the bacterial genome, and a lytic state occurs.

A

temperate phage

70
Q

During this process, adjacent bacterial genes may be excised with the phage DNA and packaged into the new phage. The bacterial genes may be transferred when the phage infects a new bacterium. In the field of biotechnology, phages are often used to insert cloned genes into bacteria for analysis.

A

Lytic stage

71
Q

is the transfer of genetic material from a donor bacterial strain to a recipient strain

A

Conjugation

72
Q

Conjugation

In the E. coli system, the donor strain (F+) possesses a fertility factor (F factor) on a plasmid that carries the genes for conjugative transfer. The donor strain produces a hollow surface appendage called a_______, which binds to the recipient F− cell and brings the two cells in close contact.

A

sex or conjugation pilus

73
Q

When the F factor is integrated into the bacterial chromosome rather than a plasmid, there is a higher frequency of transfer of adjacent bacterial chromosomal genes. These strains are known as…

A

high-frequency recombination strains

Bacte LEC (15 decks)

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