Viruses

Question 1

What are viruses?

Answer 1

Non living, lack cellular structure, don’t carry out cellular processes

Question 2

Viruses must be in a host cell to produce

Question 3

Viruses can be classified based on…

Answer 3

Disease they cause, size and shape, nucleic acid structure

Question 4

Viruses that infect bacteria are called…

Answer 4

bacteriophages

Question 5

Different shapes of viruses are…

Answer 5

Polyhedral, cylindrical, alien shape, spherical

Question 6

2 types of nucleic structure are…

Answer 6

RNA viruses: more common, more errors during replication, higher mutation rates

DNA viruses: less common, less errors during replication, lower mutation rates

Question 7

The lytic cycle

Answer 7

depends on the metabolism of the host cell to replicate DNA or RNA

Question 8

Steps of Lytic cycle are..

Answer 8

Attachment: virus attatches to host cell and injects nucleic acid into cell

Synthesis: virus DNA takes over host cell and programs it to replicate its DNA

Assembly: All components of virus come together to create new virus particles

Release: Host cell breaks open and new virus particles are released. Host cell dies

Question 9

Lytic cycle makes us feel..

Answer 9

sick! because of the bursting of cells which gives us symptoms and makes us feel bad

Question 10

Lysogenic cycle

Answer 10

Virus is hidden in DNA until it wants to attack

Question 11

Lysogenic cycle steps…

Answer 11

1. Attachment: Virus attaches to cell, DNA enters and integrated itself into hosts cells DNA
2. Reproduction: Virus DNA makes copies of itself during normal mitosis of the cell
3. Cytokinesis: Daughter cells of mitosis have virus DNA integrated with their own and the cycle continues

Question 12

Viruses can alternate between both the lysogenic cycle and lytic cycle. What virus alternates between the 2?

Answer 12

HIV has an enzyme that transcribes RNA to DNA. This DNA can then insert itself into host cell and make copies of itself as cell divides.

Question 13

Example of virus going through lysogenic and lytic cycle?

Answer 13

Herpes: sores appear during lytic cycle when host cells are destroyed. but disappear during lysogenic cycle when viral DNA is incorporated into host cell DNA

Question 14

Why are viruses important?

Answer 14

• Ability to spread
• Can cause epidemic or pandemic
• Some can increase cancer risk
• Kill crops and livestock
• in gene therapy you can kill cancer cells

Question 15

What are vaccines?

Answer 15

Train our bodies to defend against the virus by injecting dead or weakened viruses into our bodies. Immune system will build antibodies against it

Question 16

What are Prions?

Answer 16

Proteins found in all body tissues but at high levels in the brain. Only disease causing agents that don’t have DNA or RNA.

Question 17

How can disease start from prions?

Answer 17

When prions(proteins) aren’t folded correctly and covert normal shaped proteins into a harmful shape. When prions get into our brain, proteins become misshaped and brain cells start dying.

Question 18

HIV contains Reverse transcriptase, what does it do?

Answer 18

when RNA goes to DNA

Question 19

Lysis

Answer 19

To burst

Question 20

Lysogenic cycle only becomes active when..

Answer 20

change in environment

Question 21

Retrovirusses

Answer 21

can alternate between lysogenic cycle and lytic cycle

Question 22

Prions are found all over the body but highest in the brain

Question 23

Prions are the only disease agents that don’t have…

Answer 23

DNA or RNA

Question 24

Prions cause..

Answer 24

Crutezfeldt- Jakob Disease, which is related to mad cow disease

Question 25

What surrounds DNA or RNA in virsuses?

Answer 25

Capsid

Question 26

What do antibodies do?

Answer 26

When future exposure occurred, antibodies will be ready to fight off virus