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BIO 2104 > VIRUSES CH 7 > Flashcards

VIRUSES CH 7 Flashcards

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Biology 101 flashcards
1
Q

Identify better terms for viruses rather than alive or dead

A

Active / Inactive

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2
Q

T/F: Viruses are alive

A

False

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3
Q

Why cant viruses survive outside of a host cell?

A

They lack cell machinery

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4
Q

Identify the structures common to all viruses

A
  • Capsid (protein coat)
  • Nucleic Acid (DNA OR RNA)
  • Spikes (Allow attachment to cell surface)
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5
Q

Identify the structures present in some viruses

A
  • Accessory Proteins (specialized effects within the cell; “nice to have”)
  • Envelope (extra outer layer made from OUR cell membrane acquired when they enter the cell to hide from our immune system) (or nuclear membrane as they leave the nucleus)
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6
Q

Identify the following structures; select which are present in all Viruses, AND describe their function

A

A - Accessory Proteins (specialized effects within the cell; “nice to have”)
B - Envelope (extra outer layer made from OUR cell membrane acquired when they enter the cell to hide from our immune system)
C - Spikes (Allow attachment to cell surface + allows them into the host)*
D - Capsid (Protein Coat)*
E - Nucleic Acid (DNA OR RNA; this is used to make more viruses)*

*Present in all viruses

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7
Q

Identify and describe the different viral shapes

A

Icosahedral - 3D Hexagon
Helical - Spiral Rods
Complex (bacteriophage) - Head, Tail, + Legs

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8
Q

Identify the viral shape

A

A - Icosahedral
B - Helical
C - Complex (Bacteriophage) (Only Infect Bacteria)

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9
Q

Enveloped vs Naked Viruses

A

Enveloped - Contain the host’s phospholipid bilayer;
allows it to go unrecognized by the immune system

Naked - Lack an envelope

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10
Q

Where are spike proteins attached?

A

On the outermost membrane of the virus
Naked: On the Capsid
Enveloped: On the Envelope

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11
Q

How do viruses leave the cell?

A

Naked Viruses have spikes on the capsid + must fill the host cell with viral particles to get out; When the cell is entirely filled the host cell breaks apart through lysis

Enveloped Viruses have spikes on the cell membrane + are wrapped as they leave the host cell; this is called budding

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12
Q

T/F: Viruses can be seen with a light microscope

A

False; they require electron microscopes

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13
Q

Viral Capsids are composed of what biochemical group? What are these individual subunits called

A

Protein; Capsomeres

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14
Q

What are the three unique forms of viral nucleic acid?

A

DNA
RNA
Reverse Transcriptase - RNA >DNA

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15
Q

Describe the viral life cycle

A

APUSAR
Adsorption - Spikes to stick to receptors on host cell

Penetration - Entry into the cell

Uncoating - Break capsid open + release nucleic acid

Synthesis - Form more viral capsids + nucleic acids

Assembly - Use capsids and nucleic acid to form more infectious particles +

Release - Leave to infect more cells

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16
Q

DNA vs RNA Virus

A

DNA Virus must go to the nucleus to trigger protein formation (DNA > mRNA > Protein)

RNA Virus stays in the cytoplasm (can make proteins within the cytoplasm)

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17
Q

What are the two things we want to know about a virus? Why?

A

DNA or RNA:
DNA virus goes to the nucleus to be turned into RNA and have an effect as proteins
RNA virus doesn’t need to go to the nucleus and can be translated in the cytoplasm

Naked or Envoloped:
Naked virus has spikes on the capsid and causes lysis to get out of the cell (must fully fill the cell with viral particles)
Enveloped virus sends spikes to the cell membrane and are wrapped around the virus on the envelope as they leave the cell

18
Q

Define Provirus and Latent Phase

A

Inserts viral DNA into the host DNA; Can go into a latent phase where the trait is inactive but can be reactivated

19
Q

Oncogenic Virus

A

Cancer causing virus
~13% of human cancer is caused by viruses

20
Q

In Vitro vs In Vivo

A

They are both processes by which we grow viruses

In Vitro - Cells on a plate
In Vivo - Lab animals and bird eggs

21
Q

T/F: Viral infections are more common than bacterial infections

A

True

22
Q

T/F: Viral mutation rates are low and viruses are easy to track in a population

A

False; they mutate all the time and are impossible to track in a population

23
Q

Doctors + Scientists most often rely on _______ to treat or prevent viral infections

A

Vaccines

24
Q

Why is it difficult to create antiviral treatments?

A

Viruses use much of human machinery and therefore makes it difficult to target specific features without harming our own cells

25
Q

What are prions?

A

Misfolded Proteins

26
Q

How are prions misfolded?

A

Alpha helices are mutated to form beta pleated sheets

27
Q

What organ do prions primarily affect?

A

Mainly the brain but also other regions of the nervous system including the spinal cord

28
Q

Virus is the latin word for ________

A

Poison

29
Q

Why are viruses considered obligate intracellular parasites? What host cell machinery do they use?

A

They must be inside of a cell and use host ribosomes and enzymes to make more viral DNA/RNA, spikes, and capsomeres

30
Q

What is the size range of viruses? How do we view them?

A

Nanometer range; require electron microscopes

31
Q

Genome

A

The full complement of dna and rna carried by a cell

32
Q

Is the flu an RNA or DNA virus?

A

RNA

33
Q

Is AIDS/HIV an RNA or DNA Virus?

A

RNA

34
Q

List characteristics of viruses that distinguish them from cellular life

A

They lack ribosomes, enzymes, and hormones. They do not reproduce, and do not perform metabolism or chemical reactions

35
Q

What enzymes do viruses use to speed up their processes within the host cell? How do they work?

A

Polymerases - Synthesizes DNA and RNA
Replicases - Copy RNA

36
Q

How does reverse transcriptase work? What virus is known to have this enzyme?

A

Turns RNA into DNA and imbeds viral DNA in OUR genome
HIV

37
Q

How do we meausre the amount of virus in a sample?

A

Put cells in a plate and cover the entire plate in agar; we then measure plaques; or the absence of cells in an area

38
Q

T/F: The term plaques is only used to describe the effects of bacteriophage on cell cultures

A

False

39
Q

How do vaccines work?

A

They are inactive viruses that teach our immune system how to respond to it so that we can fight it quicker with less symptoms and damage

40
Q

what disease do prions cause?

A

Spongiform Encephalopathies (spongy brain)

41
Q
A

BIO 2104 (10 decks)

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