Ch. 24.2 Viruses

Question 1

Are viruses living things?

Answer 1

No, they only possess portion of properties of living organisms

Question 2

Do viruses have cell membrane or cellular organelles?

Answer 2

No, viruses don’t have cell membrane or cellular organelles

Question 3

What are viruses’ hereditary material?

Answer 3

DNA or RNA

Question 4

Do viruses replicate outside of host cell?

Answer 4

No, they don’t

Question 5

What do viruses infect?

Answer 5

Viruses infect specific cell types that hs the receptors viruses can bind to

Question 6

What does hepatitis of viruse infect?

Answer 6

Hepatitis only infect liver cells

Question 7

What are zoonotic viruses?

Answer 7

Viruses that can bind to similar receptors in more than one species

Question 8

What is the example of zoonotic viruses?

Answer 8

Influenza that bind to birds, humans, or pigs

Question 9

What is the mutation rate of virus?

Answer 9

Viruses have high mutation rate therefore they are likely to cause pandemics

Question 10

What are bacteriophages?

Answer 10

Bacteriophages are viruses that infect bacteria

Question 11

What is lytic cycle?

Answer 11

Viruses kill the infected host and replicating (spreading)

Question 12

What is lysogenic cycle?

Answer 12

virus integrates itself into the host genome but does not replicate

Question 13

What is prophage?

Answer 13

Virus residing in the host

Question 14

What cycles does virus that infect humans have?

Answer 14

It can either be lytic cycle or both lytic and lysogenic cycles

Question 15

What is Attachment for lytic and lysogenic Cycles?

Answer 15

The proteins on the virus capsid bind to a specific receptor

Question 16

What is Infiltration for lytic and lysogenic Cycles?

Answer 16

The host cell takes up the virus

Question 17

What is Replication for lytic and lysogenic Cycles?

Answer 17

The virus uses host cell organelles, nutrients, and ATP to make new virus particles

Question 18

What is Assembly for lytic and lysogenic Cycles?

Answer 18

New virus particles form and are released from the host cell, causing lysis and death of the host cell

Question 19

How does virus with RNA replicate within host cell?

Answer 19

Viruses that contain RNA must convert to DNA before they replicate within the host cell

Question 20

What is the enzyme reverse transcriptase?

Answer 20

Process of viruses that contain RNA converting into DNA

Question 21

Is it viruses with RNA or DNA that mutate more rapidly? and what is the reason behind that?

Answer 21

It is VIruses with RNA that mutate more rapidly because reverse transcriptase make mistakes during replication due to the lack of proofreading ability

Question 22

What are the examples of viruses with RNA?

Answer 22

Examples of RNA viruses include HIV, influenza, SARS, hepatitis,
measles, and polio

Question 23

What does HIV infect?

Answer 23

HIV infects only certain white blood cells within the human bloodstream (immune cells)

Question 24

What are specific cells that HIV infect?

Answer 24

CD4+ T cells but also macrophages and dendritic cells

Question 25

What does HIV infection lead to?

Answer 25

HIV infection leads to a low level of properly functioning immune cells

Question 26

What happens if level of functioning immune cells decrease?

Answer 26

When immune cell numbers decline below a critical level, the body becomes progressively more susceptible to opportunistic infections

Question 27

What happens if HIV infection is untreated?

Answer 27

If untreated, eventually most HIV-infected individuals develop AIDS (acquired immunodeficiency syndrome)

Question 28

Explain Rhinovirus, adeno-virus, and respiratory syncytal virus of viruses

Answer 28

Infected on sinuses and upper airways: Over 100 viruses cause common cold and killed by immune system; Symptoms include stuffed or runny nose, sneezing, sore throat, and coughing usually don't last longer than 7 days to 10 days

Question 29

Explain influenza of viruses

Answer 29

Infected on sinuses and upper airways: There are A, B, and C type influenza A and B being most common that is similar to common cold, influenza is RNA virus which spread and mutates faster may leading to second opportunistic infection

Question 30

Explain Herpes of viruses

Answer 30

Infected on Lips or genitals, and sensory neurons: DNA virus causing cold sores or genital herpes transmittied by skin to skin contact having a period and re-appears when it's infected during lytic cycle; easily treated by antiviral medication

Question 31

Explain Human papilloma viruses (HPV) of viruses

Answer 31

Infected on keratinocytes of skin:100 strains of HPV viruses that cause warts but mostly cause no symptom; some strains cause wart from 30-40% of sexual contaction and two strains cause female cervical cancer

Question 32

Explain hepatitis of viruses

Answer 32

Infected on liver: Inflammation of liver caused by 5 types of hepatitis which are A, B, C, D, and E; A and E are cause through contaminated food or water causing no major disease while B, C, D are transmitted through body fluid especially B and C cause chronic disease in millions of people

Question 33

Explain Rotavirus of viruses

Answer 33

Infected on gastrointestinal tract: common intestinal infection in children, almost all children will have the infection by 5 giving them antibodies that will protect them against future disease; adults barely has it

Question 34

Explain Epstein-Barr virus (EBV), mononucleosis of viruses

Answer 34

Infected on B cells and epithelial cells: Herpes virus transmitted through saliva; 90 % of adults has this infection by 40, common viral infection which cause asymptomatic in young ones to severe fatigue that last months and fever, sore throat,swollen lymph nodes