Brainscape's Knowledge GenomeTM

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


See full index

Fundamentals of Life Science > Genetics of Bacteria > Flashcards

Genetics of Bacteria Flashcards

You may prefer our related Brainscape-certified flashcards:
Biology 101 flashcards
1
Q

What is a gene?

A

smallest region of DNA (or RNA) that encodes a polypeptide or is transcribed (RNA)

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

What is an allele?

A

an alternate form of a gene

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

What is a wild type organism?

A

an organism that carries standard/reference gene which is usually but not always functional

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

What is a mutant organism?

A

carries altered form of gene(s)

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

What is a genotype?

A

genetic or allelic composition of a strain

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

What is a phenotype?

A

the observable properties of a strain

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

Does the bacterial genome contain introns?

A

no

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

What is sequencing used for?

A
  • understanding how genomes work
  • identification of pathogenicity and resistant genes
  • epidermiology
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

What is the core genome?

A

the group of essential genes and other genes found in all representatives of the species

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

What is the accessory genome?

A

genes present in some members of a species but not all e.g antibiotic resistance on some plasmids

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

Describe how the initiation occurs in replication of the bacterial chromosome

A

Initiation:

  • replication is always initiated at the same segment of DNA: oriC which is fixed to the cell membrane
  • initiation is started by the accumulation of initiation protein DnaA to oriC
  • DnaA melts the `DNA then DnaB is recruited (a helicase) to unwind DNA
  • DnaB opens replication forks in both directions (bidirectional replication)
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

Describe elongation in chromosome replication

A

the process of elongation involves the movement of replication forks and synthesis of new DNA complementary to the melted template strands

  • primase (DnaG) lays down an RNA primer and DNA polymerase III copies the DNA
  • okazaki fragments allow the lagging strand to be synthesised
  • DNA ligase joins Okzaki fragments, together in the lagging strand
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

Describe termination in chromosome replication

A

it occurs when the replication forks reach the part of the chromosome opposite oriC at ter sites (which prevent helicase activity)
-completed chromosomes are interlinked and need to be resolved by topoisomerase to separate them

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

How are bacterial genes often organised?

A

in polycistronic operons consisting of genes of related function

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

How does bacteria control gene expression?

A

by controlling transcription

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

In what ways can you influence the rate of transcription?

A
  • promoter structure (strength)
  • operators/enhancers
  • operons/regulons
  • transcriptional regulators (+ve and -ve)
17
Q

What does the sequence of a promoter region influence?

A

how well RNAP binds

18
Q

How do transcriptional regulator effect the rate of transcription?

A

-by helping/hindering the binding of DNA

19
Q

What is the action of regulators often influenced by?

A

the environment

20
Q

What is a regulon?

A

When genes with similar functions and therefore similar sequences can be turned on or off together

21
Q

Why do bacteria evolve fast?

A
  • rapid generation rates
  • very large populations
  • programmed mutations
22
Q

How does evolution occur?

A

when an alteration to the genome occurs, followed by selection

23
Q

How can DNA change?

A
  • mutation

- acquisition of new DNA

24
Q

What is a same-sense mutation?

A

when the same amino acid is encoded

25
Q

What is a mis-sense mutation?

A

different aa encoded

26
Q

What is a nonsense mutation?

A

stop codon encoded

27
Q

What is a programmed mutation?

A

when some genes are turned on or off at high frequency

genes known as phase variable

28
Q

What are the mechanisms of phase variation?

A
  • genomic variation
  • strand slippage
  • methylation
29
Q

What are the three mechanism that DNA can be exchanged by?

A

conjugation
transduction
transformation

30
Q

What are the two ways that transposition can occur?

A
  • copy and paste mechanism (class II transposition) sequence coped to RNA and then into DNA (by reverse transcriptase) and is inserted elsewhere
  • cut and paste mechanism (class II transposition) transposon cur out of DNA and inserted elsewhere by resolvase
31
Q

How are transposons related to antibiotic resistance?

A

-capture resistance genes and transfer them between chromosomes/plasmids and therefore between species/strains

32
Q

How does transduction occur?

A
  • phage infects bacterial cell
  • DNA injected and inserts randomly in host chromosome
  • when lytic cycle s initiated phage DNA excised +/- some host DNA
  • new phage particles synthesised
  • bacterial cell lyses releasing particles
  • infect new cell and may carry DNA from previous host
33
Q

What is transformation?

A

-uptake of naked DNA from environment by competent bacteria

Fundamentals of Life Science (28 decks)

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