Biology- Ch. 24 Flashcards
Who was the first scientist to crystallize a virus? What virus was it?
Wendell Stanley crystallized the Tobacco Mosaic virus
A give an example of a disease associated with each viral capsid shape
Helical- tobacco mosaic virus-rabies- genome is spiral shape
Icosahedron- chickenpox- genome is circular or linear shape
Spherical- HIV- genome is sphere shape
Which macromolecule is the capsid primarily made up of?
Protein
What is a viral envelope, and where does a virus get one?
An envelope is a phospholipid belayer and it acquires it from the host cell membrane
In what different ways might viruses be classified?
Viruses can be classified by if they have DNA or RNA, the shape of their genome, whether they have an envelope
What is a bacteria called once it has been infected with a virus?
Prophage
Describe the lyric and lysogenic cycles of viruses in prokaryotes
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
Some facts about lytic cycle
Lytic is variant. Lytic kills host cell
Some facts about lysogenic cycle is?
Lysogenic is more temperate, puts genome into host cell.
How do scientists think the first viruses originated?
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.
What are some vectors, and what are some common vectors?
Vectors are the transferee of the virus for example mosquitoes and humans
What virus causes chickenpox?
Chickenpox are caused by a varicella- zoster herpesvirus.
What is shingles, and who gets shingles?
Shingles is a dormant type of chickenpox that adults might get if they have had chickenpox before.
What is hepatitis?
Hepatitis is inflammation of the liver. It can be caused by the hepatitis virus
How are different strains of hepatitis transmitted?
Hepatitis A and E can be spread by fecally contaminated food and water. Hepatitis B and C and D are spread by sexual contact.
Explain the mechanics of HIV infection?
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.
How do some viruses lead to cancer?
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.
What are the three primary actions taken to treat or prevent viral infection?
Three primary actions are vaccinations, factor control, and drug therapy.
What is a viroid?
A naked piece of nucleic acid capable of entering a cell in causing disease
