Microbial Genetics Flashcards

1
Q

what are plasmids and what do they do

A

Small circles of ds DNA

Encode inessential genes that give the bacterium a selective adv.

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2
Q

An F+ bacteria means..

A

it is cabable of producing a pili

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3
Q

where does DNA replication/ transcription and translation take place in eukaryotes and prokaryotes

A

rep- Eukaroyes (nuclei), Pro (cytosol)
Transcription- Euk (nuclei), Pro (cytosol)
Translation- In cytosol

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4
Q

How does DNA replication start in eukaryotes

A

Starts @ origin

Helicase binds to origin and unwinds seperate DNA strands

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5
Q

Which direction does dna replication go and what are the 2 strands

A

occurs in 5 to 3 direction

leading strand- replicated continously towards fork
lagging strand- produces okazaki fragments away from fork

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6
Q

What are the enzymes needed in the replication process

A
  • Primase is starting point for fragments
  • DNA polymerase adds complementary nucleotides to new strand in 5 to 3 direction
  • DNA ligase fills in any gaps

Overall one strand new and one old (semiconservative)

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7
Q

What are telomeres made of

A

hundreds of TTAGGG repeats at the end of eukaryotic dna to prevent loss of genes

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8
Q

How many origin points does prokaryotic DNA replication have

A

multiple

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9
Q

In bacteria what is the main enzyme involved in repication

A

DNA polymerase II

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10
Q

What is an aditional enzyme bacteria need for replication and function

A

Bacteria require DNA gyrase to resolve supercoils in its circular genome

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11
Q

What does topisomerase IV do in dna replication in bac

A

after replication it cuts and reseals the circular dna

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12
Q

What are the steps of rolling circle replication

A
  • repA nicks outer strand
  • DNA polmerase binds to intact strand which is used as template
  • nicked strand displaced
  • displaced strand is then coppied to dsDNA
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13
Q

How does viral dna replicate (3 ways)

A
  • be used directaly as template
  • linear dna circulizes in rolling circle replication
  • Integrate into host genome
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14
Q

How do transcription factors (actiavtors/repressors) affect transcription

A

Need all the activators and no repressors

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15
Q

What seperates the strands in transcription

A

RNA polymerase

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16
Q

What does RNA pol I, II, III corespond to

A

I- rRNA
II- mRNA
III-tRNA

17
Q

What are the post trascriptional modifications (4)

A

5’ cap
Poly A tail
removal of introns
alternative splicing

18
Q

What are introns

A

regions of mRNA that do not code for proteins that need to be spliced out

19
Q

what is alternative splicing

A

selected exons can be spliced out in order to have one section code for multiple pros

20
Q

How are viral proteins translated

A

viruses utalize the ribosomes of the cells they infect to make their pros
(can also be translated into large polypros that are trimmed down into other functional pros via proteases)

21
Q

What does RNA dependent polymerase do

A

allows viruses to amplify their dna by being able to convert from + sense to - sense and back

  • in -sense they can amplify their rna
22
Q

What are group 3 viruses and how do they amplify rna

A

DSRNA
has + and - strand
negative used to amplify then go back to positive to create pros

23
Q

What are group 4 viruses and how do they amplify rna

A

(+) ssRNA

can change to - sense to amplify

24
Q

What are group 5 viruses and how do they amplify rna

A

(-)ssRNA

can change to + to make pro or used as templates to create more +

25
Q

What can group 6 and 7 viruses do

A

can convert its rna to dna

must convert into host dna after

26
Q

What happens in binary fission and who performs it

A

cell elongates and divides into 2 identical daughter cells

-primary for bac, mito

27
Q

Whatt happens in budding and who performs it

A

new organism develops from outgrowth or bud due to cell division at one site

-certain yeasts, molds, protozoa + helminths

28
Q

What happens in fragmentation and who performs it

A

A piece of organism breaks off and fragment develops into matured organism

some pathogenic molds

29
Q

Why would fungi perform sexual repro instead of asexual

A

fungal secual repro stage is usually associated with adverse env conditions

30
Q

What is conjugation

A

transfer of genetic info bw bacterial cells via pili (only f+ bac)

-plasmids comonly transfered

31
Q

What is transduction

A

process by which dna is transfered from one organsim to another (ex bacteriophage)

32
Q

What is transformation

A

process in which the genetic makeup of a bacterial cell is changed by intro of free DNA from surrounding env.