Question 1

Introduction and History
History
 1.1884 Pasteur -
2.1892 Iwanowski & 1898 Beijerinck -

Accepted Answer

1.-developed first vaccine for rabies
 -proposed the term “virus” to denote this special  group
2. Discovered the fluids from infected tobacco plants could  be filtered off all cells, but still remained contagious.   Something smaller than bacteria was

Question 2

cont.
3. 1935 
4.1940’s

Accepted Answer

3. Biochemist Wendell Stanley
  purified and crystallized tobacco mosaic
  virus.
4.With the advent of the electron microscope we could finally see viral shapes and sizes.

Question 3

Characteristics of Viruses
1. Virus

Accepted Answer

-Minuscule, acellular infectious agent
-Causes many infections of humans, animals, plants, and bacteria
-Causes most of the diseases that plague the industrialized world

Question 4

Viruses: Alive or not?	Viruses have living & nonliving characters

1. Alive
2.Nonliving

Nonliving don’t have?

Accepted Answer

1. Nucleic acids
Reproduction
Respond to stimuli
Evolve

2.DNA or RNA, not both
Obligate intracellular parasite
Can be crystallized
No growth or metabolism
No cell structure

Nonliving don’t have cell structure, nucleus, enzyme, mitochondria an

Question 5

what are structure?

Accepted Answer

-Size and morphology
-Capsid
-Envelope
-Complex
-Nucleic acid

Question 6

Structure of Viruses
-Size range

Accepted Answer

-smallest infectious agents

-ultramicroscopic (<0.2 micrometers) an 	electron microscope is necessary to 	examine them.

- 2,000 bacteriophages could fit inside an 	average bacterial cell. 50 million poliovirus 	could fit in an average human cell.

Question 7

Viral structures- no cell structure so what is it?

-  3 possible pieces to viruses
1. Nucleic acid core 
2. Capsid 
3. Envelope

Accepted Answer

1. one or many strands of DNA or RNA but not both
2. protective outer shell made of protein subunits called capsomeres

3.optional, not all viruses have this.Usually a modified piece of the hosts cell membrane.

Question 8

Nucleic acid


-Unlike cells, viruses contain either DNA or RNA, but not both
-Possess only the genes to invade and regulate the metabolic activity of host cells

Accepted Answer

-Ex. Hepatitis B (4 genes) and herpesviruses (100 genes)
-No viral metabolic genes, as the virus uses the host’s metabolic resources

Question 9

Nucleic acid core
- Viral Nucleic acids must contain instructions for at least 4 things

Accepted Answer

1. Genes for regulating the actions of the host
2. Genes for synthesizing the viral genetic
    material
3. Genes for synthesizing the viral capsid and
    proteins
4. Genes for assembling and packaging the
    mature virus.

Question 10

1.-Viruses only contain ? 1. DNA or RNA but not both.
2. Viruses may contain?


-Some viruses will have a few enzymes like 
     polymerases, or in the case of HIV reverse
     transcriptase for making DNA from RNA.

Accepted Answer

2.dsDNA*, ssDNA, dsRNA, and
     ssRNA*.

-Gene numbers range from 4 in hepatitis B to
     hundreds in herpesviruses. E. coli has 4,000 and
     humans have 30-40,000.

Some viruses will steal items from the host cell like ribosomes or tRNA.

Question 11

Characteristics of Viruses

Viral Shapes
- Three basic shapes

Accepted Answer

Helical
Polyhedral
Complex

Question 12

Capsid?

Two types of capsids?

Accepted Answer

-Protective outer shell that surrounds viral nucleic acid 
-Capsid spikes
-Composed of capsomer subunits

2: 1.Helical
2.Icosahedral

Question 13

Capsid-

Multiple shapes?

Accepted Answer

protein coat surrounding nucleic acid core, made of identical subunits called capsomeres, that spontaneously self-assemble

MS- either Icosahedral or Helical
- Icosahedron, 3 dimensional, 20 sided, with 12 evenly spaced corners

Question	Answer
Introduction and History History 1.1884 Pasteur - 2.1892 Iwanowski & 1898 Beijerinck -	1.-developed first vaccine for rabies -proposed the term “virus” to denote this special group 2. Discovered the fluids from infected tobacco plants could be filtered off all cells, but still remained contagious. Something smaller than bacteria was
cont. 3. 1935 4.1940’s	3. Biochemist Wendell Stanley purified and crystallized tobacco mosaic virus. 4.With the advent of the electron microscope we could finally see viral shapes and sizes.
Characteristics of Viruses 1. Virus	-Minuscule, acellular infectious agent -Causes many infections of humans, animals, plants, and bacteria -Causes most of the diseases that plague the industrialized world
Viruses: Alive or not? Viruses have living & nonliving characters 1. Alive 2.Nonliving Nonliving don’t have?	1. Nucleic acids Reproduction Respond to stimuli Evolve 2.DNA or RNA, not both Obligate intracellular parasite Can be crystallized No growth or metabolism No cell structure Nonliving don’t have cell structure, nucleus, enzyme, mitochondria an
what are structure?	-Size and morphology -Capsid -Envelope -Complex -Nucleic acid
Structure of Viruses -Size range	-smallest infectious agents -ultramicroscopic (<0.2 micrometers) an electron microscope is necessary to examine them. - 2,000 bacteriophages could fit inside an average bacterial cell. 50 million poliovirus could fit in an average human cell.
Viral structures- no cell structure so what is it? - 3 possible pieces to viruses 1. Nucleic acid core 2. Capsid 3. Envelope	1. one or many strands of DNA or RNA but not both 2. protective outer shell made of protein subunits called capsomeres 3.optional, not all viruses have this.Usually a modified piece of the hosts cell membrane.
Nucleic acid -Unlike cells, viruses contain either DNA or RNA, but not both -Possess only the genes to invade and regulate the metabolic activity of host cells	-Ex. Hepatitis B (4 genes) and herpesviruses (100 genes) -No viral metabolic genes, as the virus uses the host’s metabolic resources
Nucleic acid core - Viral Nucleic acids must contain instructions for at least 4 things	1. Genes for regulating the actions of the host 2. Genes for synthesizing the viral genetic material 3. Genes for synthesizing the viral capsid and proteins 4. Genes for assembling and packaging the mature virus.
1.-Viruses only contain ? 1. DNA or RNA but not both. 2. Viruses may contain? -Some viruses will have a few enzymes like polymerases, or in the case of HIV reverse transcriptase for making DNA from RNA.	2.dsDNA, ssDNA, dsRNA, and ssRNA. -Gene numbers range from 4 in hepatitis B to hundreds in herpesviruses. E. coli has 4,000 and humans have 30-40,000. Some viruses will steal items from the host cell like ribosomes or tRNA.
Characteristics of Viruses Viral Shapes - Three basic shapes	Helical Polyhedral Complex
Capsid? Two types of capsids?	-Protective outer shell that surrounds viral nucleic acid -Capsid spikes -Composed of capsomer subunits 2: 1.Helical 2.Icosahedral
Capsid- Multiple shapes?	protein coat surrounding nucleic acid core, made of identical subunits called capsomeres, that spontaneously self-assemble MS- either Icosahedral or Helical - Icosahedron, 3 dimensional, 20 sided, with 12 evenly spaced corners

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