Biology- Ch. 24

Question 1

Who was the first scientist to crystallize a virus? What virus was it?

Answer 1

Wendell Stanley crystallized the Tobacco Mosaic virus

Question 2

A give an example of a disease associated with each viral capsid shape

Answer 2

Helical- tobacco mosaic virus-rabies- genome is spiral shape
Icosahedron- chickenpox- genome is circular or linear shape
Spherical- HIV- genome is sphere shape

Question 3

Which macromolecule is the capsid primarily made up of?

Answer 3

Protein

Question 4

What is a viral envelope, and where does a virus get one?

Answer 4

An envelope is a phospholipid belayer and it acquires it from the host cell membrane

Question 5

In what different ways might viruses be classified?

Answer 5

Viruses can be classified by if they have DNA or RNA, the shape of their genome, whether they have an envelope

Question 6

What is a bacteria called once it has been infected with a virus?

Answer 6

Prophage

Question 7

Describe the lyric and lysogenic cycles of viruses in prokaryotes

Answer 7

Lyric cycle- 1) virus attaches and injects DNA into host cell,2) virus circularizes,3) new virus is made,4) kills host by cell lysing. Lysogenic- 1) virus attaches and injects DNA into host cell, 2) DNA is integrated into host DNA,3) host replicated,4) may continue or enter lyric cycle

Question 8

Some facts about lytic cycle

Answer 8

Lytic is variant. Lytic kills host cell

Question 9

Some facts about lysogenic cycle is?

Answer 9

Lysogenic is more temperate, puts genome into host cell.

Question 10

How do scientists think the first viruses originated?

Answer 10

Likely originated from a naked piece of nucleic acid that entered a cell with a damaged membrane. Evolution would have provided the Capsid over time.

Question 11

What are some vectors, and what are some common vectors?

Answer 11

Vectors are the transferee of the virus for example mosquitoes and humans

Question 12

What virus causes chickenpox?

Answer 12

Chickenpox are caused by a varicella- zoster herpesvirus.

Question 13

What is shingles, and who gets shingles?

Answer 13

Shingles is a dormant type of chickenpox that adults might get if they have had chickenpox before.

Question 14

What is hepatitis?

Answer 14

Hepatitis is inflammation of the liver. It can be caused by the hepatitis virus

Question 15

How are different strains of hepatitis transmitted?

Answer 15

Hepatitis A and E can be spread by fecally contaminated food and water. Hepatitis B and C and D are spread by sexual contact.

Question 16

Explain the mechanics of HIV infection?

Answer 16

Enters through infected bodily fluids. Uses reverse transcriptase to make viral DNA from its RNA 1st enters macrophages begins replication and adds marckers to newly made viruses. New viruses are released and infect T- lymphocytes and May progress to AIDS.

Question 17

How do some viruses lead to cancer?

Answer 17

If viral DNA is inserted near oncogene(control normal cell division) it may cause uncontrolled cell division and result in a tumor. Proto- oncogene (control cell growth) and if viral DNA is inserted on/near can lead to uncontrolled cell growth human papilloma virus.

Question 18

What are the three primary actions taken to treat or prevent viral infection?

Answer 18

Three primary actions are vaccinations, factor control, and drug therapy.

Question 19

What is a viroid?

Answer 19

A naked piece of nucleic acid capable of entering a cell in causing disease