Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

Bacteriology > Genetics and Genomics > Flashcards

Genetics and Genomics Flashcards

1
Q

Describe the genome of most bacteria

A

Single, circular chromosome with dsDNA

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

What is a bacterial plasmid?

A

Mini-chromosomes of closed circular DNA associated with important characteristics to enable plasmid-transfer.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

Are there only one copy of a plasmid in bacterium?

A

No, there can be multiple copies

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

What is DNA supercoiling?

A

A method of packaging a large amount of genes into the bacterial cell.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

What proteins facilitate supercoiling?

A

Histone-like proteins, topoisomerases, DNA gyrase

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

What enzymes are the target of Quinolone abx?

A

Protein supercoiling proteins - histone-like proteins, topoisomerases, DNA gyrase

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

How is the bacterial genome split?

A

Core genes present in all strains and accessory genes present in specific/subsets of strains

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

What is the pangenome?

A

Gene pool of a species
Accessory + core genes

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

What are the mechanisms for generating diversity?

A

Point mutations/SNPs
Insertions and Deletions
Horizontal Gene Transfer

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

What is a point mutation or single nucleotide polymorphism?

A

Mutations during replication that change only one base pair

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

What are the results of SNPs?

A

Silent, Missense, Nonsense mutations

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

Give an example of an SNP

A

Mutation in DNA gyrase that causes an amino acid change to leucine, thus preventing the binding and activity of ciproflaxacin abx.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

What is Horizontal Gene Transfer (HGT)?

A

The movement of genes between bacteria

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

What are the three main mechanisms of HGT?

A

(Phage) Transduction
Transformation
Conjugation

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

Describe the process of phage transduction

A
  1. Bacteria phage attaches to the surface and inserts DNA
  2. Phage replication - Phage can excise part of bacterial genome
  3. Bacterial cell lysis and phage release
  4. Phage can move gene to another bacteria when restarting new replication cycle
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

Describe the process of transformation

A

Free linear DNA binds to and is taken up by a bacterium.
Can be integrated into chromosome or exist as a self replicating plasmid element.

17
Q

What is bacterial conjugation?

A

Genetic transfer through cell to cell contact.
Plasmid encoded mechanism with a donor and recipient cell.

18
Q

Describe the process of bacterial conjugation

A
  1. Expression of and contact through sex pilus
  2. Rolling circle replication and transfer of plasmid copy to the second cell
19
Q

How does HGT impact the bacteria?

A

Allows individuals to acquire accessory genes or ‘tools’ that can increase their ability to cause disease or infect different hosts/sites.

20
Q

Why do variants in species exist?

A

Due to variation in the tools that strains acquire, which thus allow them to cause different types of infection or survive in different environments.

21
Q

What are the main mechanisms of antibiotic resistance?

A

Drug inactivation or modification
Target modification/replacement/overproduction
Drug efflux
Reduced drug uptake

22
Q

What is the difference between intrinsic and acquired resistance?

A

Intrinsic - All strains of a species are resistant
Acquired - SOME strains have acquired resistance but not all

23
Q

Are bacteria able to respond quickly to changes in their environment?

A

Yes!

24
Q

What are some environmental sensing mechanisms?

A

Activation and repression of gene expression
Two-component signal transduction systems
Quorum sensing

25
Q

Give an example of when activation or repression of gene expression is used

A

Often depends on availability of certain nutrient.
Iron levels closely monitored by bacteria as it is essential for their growth. Low levels lead to expression of bacterial factors that help them obtain iron from their host.

26
Q

What is a two-component signal transduction system?

A

A system that passes information through bacterial wall and membranes via a phosphorelay system. Component 1 senses signal, component 2 regulates the response by binding to a gene promotor and activating or repressing gene expression.

27
Q

What is quorum sensing?

A

Capacity for bacteria to monitor certain compounds released by other bacteria, and then alter gene expressions based on the density detected.

28
Q

When can quorum sensing be advantageous?

A

When high numbers of bacteria are needed for barrier invasion or toxin production.
To help define location of bacteria.

29
Q

What are the limitations of culture based diagnostics?

A

Long processing time (3 to 4 days)
Samples may be negative due to organism not being culturable.

30
Q

What are the benefits of sequence based diagnostics?

A

Faster!
Produces more extensive information that the culture methods including presence, identification, virulence information, abx resistance, etc.

Bacteriology (2 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions