Part 2

Question 1

• nucleic acid
• Single-stranded genomes may be of
  positive (i.e. mRNA) or negative (i.e. antimRNA) polarity.

Answer 1

Genome

• nucleic acid
• Single-stranded genomes may be of
  positive (i.e. mRNA) or negative (i.e. antimRNA) polarity.

Question 2

• a coat of protein arranged in one of several
  possible morphologies
• encloses the genome.

Answer 2

Capsid

• a coat of protein arranged in one of several
  possible morphologies
• encloses the genome.

Question 3

• cubical with 20 flat sides

Answer 3

Icosahedral capsid

• cubical with 20 flat sides

Question 4

• spiral

Answer 4

Helical capsid

• spiral

Question 5

• sub-unit of capsid

Answer 5

Capsomere

• sub-unit of capsid

Question 6

• Certain viruses also contain an additional
  phospholipid bilayer derived from the host
  cell and surrounding the protein capsid.

Answer 6

Envelope

• Certain viruses also contain an additional
  phospholipid bilayer derived from the host
  cell and surrounding the protein capsid.

Question 7

• glycoprotein that functions as attachment or
  as an enzyme

Answer 7

Spikes

• glycoprotein that functions as attachment or
  as an enzyme

Question 8

• a complete viral particle

Answer 8

Virion

• a complete viral particle

Question 9

• with circular RNA molecules
• without capsid and envelope

Answer 9

Viroid

• with circular RNA molecules
• without capsid and envelope

Question 10

• viroid-like particles
• passengers in virus capsids

Answer 10

Virusoids

• viroid-like particles
• passengers in virus capsids

Question 11

• believed to consist of a single type of
  protein molecule without Nucleic Acid
  content

Answer 11

Prions

• believed to consist of a single type of
  protein molecule without Nucleic Acid
  content

Question 12

Virus Classifications

Answer 12

Virus Classifications
1. According to Type of Genetic Material
a. DNA
b. RNA
2. According to Shape of Capsid
a. Helical
b. Polyhedral
o example: Icosahedral (20 sides)
3. Number of Capsomeres
4. Size of Capsomeres
5. Presence or Absence of Envelope

Question 13

Recognition and attachment to its host cell’s
carbohydrate receptors

• viruses are ________ as to the type of host cell
  in which they can multiply and so
  recognition is often very specific.
  (___________)
• Viruses adsorb to their host cell surface via
  specific ______________ molecules, often
  glycoproteins.
• Adsorption is generally _________________ and
  _________ independent.

Answer 13

Recognition and attachment to its host cell’s
carbohydrate receptors

• viruses are limited as to the type of host cell
  in which they can multiply and so
  recognition is often very specific.
  (TROPISM)
• Viruses adsorb to their host cell surface via
  specific antireceptor molecules, often
  glycoproteins.
• Adsorption is generally temperature and
  energy independent.

Question 14

Penetration into the host cell
- often energy dependent and may occur by
three different mechanisms;
a.
b.
c.

Answer 14

Penetration into the host cell
- often energy dependent and may occur by
three different mechanisms;
a. translocation of the plasma membrane
b. pinocytosis into cytoplasmic vacuoles, or
c. fusion of the plasma membrane with the viral envelope forming a SYNCYTIA

Question 15

Penetration into the host cell
- Non-enveloped viruses may enter via
________________ or _______________; enveloped
viruses typical enter via fusion. Once inside
the host cell

Answer 15

Penetration into the host cell
- Non-enveloped viruses may enter via
translocation or pinocytosis; enveloped
viruses typical enter via fusion. Once inside
the host cell

Question 16

• releases the viral genome to be replicated.

Answer 16

Uncoating
- releases the viral genome to be replicated.

Question 17

• production of _______________ and __________________
• Viral transcription leads to the synthesis of _______ (encodes early(structural) and late viral proteins)

Answer 17

Macromolecular synthesis
- production of nucleic acid and protein polymers
- Viral transcription leads to the synthesis of mRNA (encodes early(structural) and late viral proteins)

Question 18

• structural proteins, genomes and enzymes are assembled

Answer 18

Viral assembly
- structural proteins, genomes and enzymes are assembled

Question 19

Release
______
- causes rapid host cell death

Answer 19

Release
Lysis
- causes rapid host cell death

Question 20

_________
- viral envelopes are acquired from
host’s cell membrane
- may not result to rapid cell death

Answer 20

Release
Budding
- viral envelopes are acquired from host’s cell membrane
- may not result to rapid cell death

Question 21

Nonspecific defenses
__________________
 anatomical barriers,
 viral inhibitors in _______ and _________.
 Phagocytosis is somewhat ________.

Answer 21

Nonspecific defenses
Prior to infection
 anatomical barriers,
 viral inhibitors in fluids and tissues.
 Phagocytosis is somewhat variable.

Question 22

Nonspecific defenses
________________
 _____ (viral replication is strongly influenced by temperature) and
 inflammatory processes including edema, leucocyte accumulation, local hyperthermia, reduced oxygen tension and altered cell metabolism can all act to reduce _______________.

Answer 22

Nonspecific defenses
After infection
 fever (viral replication is strongly influenced by temperature) and
 inflammatory processes including edema, leucocyte accumulation, local hyperthermia, reduced oxygen tension and altered cell metabolism can all act to reduce viral replication.

Question 23

___________________
- prevent adsorption to target cells and cytotoxic T-lymphocytes, which recognize virally-infected cells and
destroy them, reducing viral production.

Answer 23

Specific host defenses
antiviral antibody
- prevent adsorption to target cells and cytotoxic T-lymphocytes, which recognize virally-infected cells and
destroy them, reducing viral production.