A2.3 Viruses + DNA replication (BOOK) Flashcards

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1
Q

For enveloped viruses, what type of cell do they usually infect?

A

Animal cells

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2
Q

In which reproductive cycle (?) of viruses are lipid envelopes common to?

A

Lytic cycle (because of lysis)

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3
Q

Describe the bacteriophage lambda on terms of the type of virus

A

Bacteriophage
- bacterium/arcaheum hosts

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4
Q

Is the bacteriophage lambda enveloped or non-enveloped?

A

Non-enveloped

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5
Q

What is the genetic material of bacteriophage lambda?

A
  • Double stranded DNA
  • both negative and positive strands
    -32 genes for 29 proteins
    -4 enzymes
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6
Q

Give the distinctive features of the bacteriophage lambda

A
  • lytic cycle OR lysogenic cycle
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7
Q

What is the host of the Bacteriophage Lambda?

A

e. coli

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8
Q

Give the parts of the bacteriophage lambda.

A
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9
Q

Describe COVID-19 (Type of Virus)

A
  • coronavirus
  • crown-like
  • animal cell host
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10
Q

COVID-19 (Enveloped or Non-Enveloped)

A

Enveloped

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11
Q

COVID-19 (Genetic Material)

A
  • 1 stranded positive sense RNA
  • 16 genes: 29 proteins
  • 6 enzymes
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12
Q

COVID-19 distinctive features

A
  • Zoonosis
  • from a bat
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13
Q

Host of COVID-19

A

Human cells and other epithelium mammal cells

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14
Q

HIV type of virus

A
  • retrovirus
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15
Q

HIV enveloped or non-enveloped

A

Enveloped

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16
Q

HIV genetic material

A
  • 2 copies of a single-stranded positive sense RNA
  • 9 genes: 15 viral proteins
  • 4 enzymes
17
Q

Host of HIV

A

T-Helper cells in the human immune system

18
Q

Give the parts of COVID 19

A
19
Q

give the parts of HIV

A
20
Q

For the lytic cycle, after lysis, how many viruses pop out?

A

~100

21
Q

How many times is the viral DNA replicated in the lytic cycle?

A
  • around 100 times by a rolling circle method
22
Q

What are the two enzymes in HIV that cause mutations ?

A
  • reverse transcriptase (for retroviruses only)
  • cytidine deaminase (general)
23
Q

Why do mutations happen more often in viruses in regards to enzymes?

A
  • They don’t proofread
24
Q

Define cytidine deaminase

A

enzyme that converts cytosine to uracil

25
Q

Why does HIV have the highest known mutation rate of any virus?

A
  • reverse transcriptase
  • cytidine deaminase
26
Q

Describe the influenza virus

A
  • enveloped
  • negative sense RNA
  • uses RNA replicase -> high mutation rate
  • haemagglutinin protein to bind to a host cell
  • neuraminidase to help with release into host cell
27
Q

What is the rule that one nitrogen base must always pair with the other?

A

Complementary base pairing

28
Q

What is the duty of DNA polymerase I?

A
  • exonuclease
  • break bonds between nucleotides and polymerase by linking nucleotides
  • replaces RNA nucleotides w/ DNA nucleotides
29
Q

DNA ligase duty

A
  • Seal the nicks left by DNA polymerase I
30
Q

How many times on a leading strand is the primer added?

A
  • 1 time
31
Q

How many times are RNA primers added to the lagging strand?

A

every 100-200 times

32
Q

In prokaryotes, who proofreads the DNA replication process and how?

A
  • DNA polymerase III
  • removes incorrect nucleotide
  • moves back 1 nucleotide
  • then inserts the CORRECT nucleotide
33
Q

Describe the procedure of the Messelsohn-Stahl Experiment

A
  • Uses E. Coli which makes DNA molecules from nitrogen compounds in their food
  • TRANSFERRED TO 15N -> 14N (old -> new) -> density
  • DNA molecules centrifuged
  • After first cell division: Mixed density (old + new)
  • After second: Mixed density + light density (mixed + just new)
34
Q

Conclusion of Messelsohn-Stahl

A
  • DNA is semi conservative
35
Q

Define dispersive

A

Each individual DNA strand is a “patchwork” of original and new DNA

36
Q

Describe gel electrophoresis

A
  • separates DNA fragments by length
  • gel placed in tank with electrolyte solution
  • DNA samples in wells
  • negative to positive movement
  • larger DNA molecules lesser + opp.
  • After, gel is treated with dye to visualize DNA
  • Visible bands
  • DNA ladder placed in one lane
  • DNA bands in other lanes
37
Q

Outline two potential applications of PCR and gel electrophoresis

A
  • testing for coronaviruses
  • DNA profiling for paternity testing
38
Q

Describe how PCR can be used to test for coronavirus

A
  • swab in nose or throat
  • RNA -> DNA BY REVERSE TRANSCRIPTASE
  • PCR to amplify specific viral base sequences that are markers
  • fluorescent markers are attached to any DNA produced
39
Q

Give the advantages and disadvantages of using PCR and gel electrophoresis for coronavirus testing

A
  • Advantage: sensitive — 1 molecule of viral DNA -> 35 bil. mol. of DNA
  • Advantage: primers can be designed so only 1 viral strain dectected
  • Disadvantage: Requires very expensive equipment
  • Due to time needed for thermal cycling, no immediate results