Brainscape's Knowledge GenomeTM


Top Flashcards (Certified)
All Flashcards

Microbiology > Genes and DNA > Flashcards

Genes and DNA Flashcards

1
Q

bacteria do not have a

A

membrane-delimited nuclei
DNA coalesces into a nucleoid

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

plasmids

A

replicate independently
are not part of nucleoid
transfer vertically and horizontally

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

DNA is a polymer of _______

A

nucleotides

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

DNA is made of

A

pentose sugar (ribose)
phosphate
nitrogenous base

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

DNA is read

A

3’ to 5’

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

DNA is built in which direction

A

new strand always 5’ to 3’

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

DNA replication in bacteria

A

starts at origin of replication
bi-directional
replication forks
forms replication bubble
proceeds in both directions until reaches the terminus

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

DNA replication process

A

gyrases relaxes supercoils
helicases separates strands
leading stand
lagging strand
requires a free 3’ OH

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

leading strand

A

continuous synthesis towards replication fork

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

lagging strand

A

discontinuous synthesis away from fork

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

discontinuous synthesis

A
  1. RNA primase generates RNA primer
  2. Pol III synthesizes DNA from RNA
  3. Pol I removes RNA primers, replaces with DNA
  4. DNA ligase bonds 3’ OH to 5’ carbon with Phosphate
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

what happens after DNA replication

A

chromosomes must be separated by Topoisomerade IV

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

transcription in bacteria products

A

mRNA: carry genetic information
rRNA: form catalytic domain of ribosome, can act as an enzyme
tRNA: carries an amino acid and decodes codons on mRNA

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

transcription in bacteria

A

initiation:
RNA polymerase binds to promoter region with sigma factor

elongation:
RNA polymerase moves along template DNA synthesizing new RNA

termination:
RNA polymerase reaches termination sequence and leaves
new RNA is released

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

sigma factor

A

provides specificity for binding

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

two methods of transcription termination

A

rho-dependent:
Rho binds sequence on RNA, moves 5’ to 3’ down RNA, separates polymerase and RNA

stem-loop structure:
complementary base-pairing, dissociates RNA polymerase, forms binding site for termination factors

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

RNA is _____ stranded

A

single stranded but molecules base pair within themselves

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

RNA helicases reduce

A

secondary structure

19
Q

ribosomes are made of

A

proteins and rRNA
large subunit: 23S rRNA
small subunit: 16S rRNA

20
Q

16S rRNA

A

highly conserved with some variable regions
can identify bacteria genera

21
Q

tRNAs

A

carry amino acids and decode codons

22
Q

codon

A

three nucleotides that are base paired by tRNA

23
Q

anti-codon

A

three nucleotides that are complementary to a codon for that amino acid

24
Q

translation in bacteria

A

initiation:
tRNA brings first amino acid in polypeptide chain to bind to start codon on mRNA, IF1 blocks A site, IF2 selects initiator tRNA

elongation:
tRNAs bring amino acids one by one to add to polypeptide chain, P site and A site

termination:
release factor recognizes stop codon, translational complex dissociates, completed polypeptide is released, E site (exit)

25
bacterial mRNA can be _______
polycistronic (encode many proteins)
26
what does no nuclear membrane allow for
simultaneous transcription and translation
27
bacteria genome organization
bacteria have operons with continuous genes under a common promoter/operator do not have introns regulatory element is an operator
28
inducer
a small molecules that activates or represses an operon
29
lactose operon
an inducible operon repressor: blocks transcription of lac operon inducer: binds to and inactivates repressor
30
the genetic code
64 codons 20 amino acids codons are: systematic or redundant start codon: AUG stop codons: UAA, UAG, UGA
31
mutations - point mutations
mutation of a single base silent: no effect on protein sequence missense: results in an amino acid substitution nonsense: substitutes a stop codon for an amino acid
32
mutations - frame shift
have a deleterious effect insertion or deletion: results in a shift in the reading frame
33
what causes mutations
spontaneous mistakes during DNA replication -DNA polymerases can proofread -removes mismatched bases chemical mutagens -mimic a nucleoside -modify a nucleoside -disrupt base pairing radiation -causes breaks in phosphate backbone or cause two adjacent thymines to dimerize -stalls DNA replication and transcription or leads to mismatches or frameshifts
34
DNA light repair
photoreactivation -uses energy of photon to break covalent bonds
35
DNA dark repair
nucleotide excision -nuclease cuts around dimer -helicase unwinds the area -DNA pol I fills the gap -DNA ligase seals the backbone
36
DNA repair base-excision and mismatch
base excision - removes base mismatch - removes segment of nucleotides
37
horizontal gene transfer
bacteria can transfer or acquire DNA from cell to cell recipient does not have to be same genus as donor
38
transformation
bacteria readily incorporate foreign DNA virulence genes transfer from heat-killed smooth strain to avirulent rough strain recovered bacteria = rough phenotype requires competence and many genes
39
conjugation
requires a Pilus 1. pilus of donor cell attaches to recipient cell 2. one strand of F plasmid DNA transfers from donor cell to recipient cell 3. donor synthesizes complementary strand to restore plasmid. recipient synthesizes complementary strand to become F+ cell with pilus
40
transduction: introducing genes by bacteriophage
viruses that infect bacteria attract parasites lytic and lysogenic replication cycles can pick up genes from one host and deposit them in another highly specific
41
replication by lysogenic phage
-phage infects cell -phage DNA incorporated into host genome -cell divides, prophage DNA passed on to daughter cells -prophage DNA is excised from bacterial chromosome and enters lytic cycle -phage DNA replicates and phage proteins are made -new phage particle are assembled -cell lyses, releasing newly made phages
42
transduction: lysogenic phage genomes can incorporate host genes
1. viral attachment and penetration 2. integration 3. excision 4. infection 5. recombination
43
transposons
jumping genes Barbara McClintock gene encoding can transfer or copy gene elsewhere in genome can transfer surrounding sequences or genes
44
transposition
1. transposon encodes enzyme transposase surrounded by inverted repeat sequences 2. transposase facilitates recombination between inverted repeats. transposon is cut from its original location and inserted into a new location

Microbiology (11 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2025 Bold Learning Solutions. Terms and Conditions