Viruses

Question 1

What are some characteristics of viruses

Answer 1

• Extremely small
• NOT living organisms
• Obligate intracellular parasites
• Only reproduce inside a living cell
• Linked with disease
• Can remain dormant
• Have different shapes

Question 2

What does obligate intracellular parasites mean

Answer 2

They force themselves into cells

Question 3

Why are viruses difficult to study

Answer 3

They need to be inside a living organisms

Question 4

What can viruses be seen with

Answer 4

Electron microscopes

Question 5

Describe the structure of a virus

Answer 5

It is acellular. It consists of a single strand of DNA or RNA. The nucleus is surrounded by a protein coat and some viruses have a waxy layer to protect the virus

Question 6

What does the waxy layer of a virus protect it from

Answer 6

The host’s nuclease enzymes

Question 7

How can we differentiate between types of viruses

Answer 7

They have different shapes

Question 8

Why are viruses parasites

Answer 8

They invade cells and are dependent on a host cell

Question 9

What is the danger on an antiviral drug

Answer 9

They harm the host cell

Question 10

What does hepatitis affect

Answer 10

The Liver

Question 11

Why are there often new flu vaccines being produced

Answer 11

Each vaccine is only effective until the particular virus mutates

Question 12

What does HIV and AIDS stand for

Answer 12

HIV: Human immunodeficiency virus
AIDS: Acquired immune deficiency syndrome

Question 13

What type of virus is HIV

Answer 13

Retrovirus

Question 14

What is a retrovirus

Answer 14

A type of virus that has RNA instead of DNA

Question 15

What does HIV do

Answer 15

Destroys CD4 cells

Question 16

What is another name for DC4 cells

Answer 16

helper T lymphocytes

Question 17

What does destruction of DC4 cells lead to

Answer 17

Immune system becoming very weak

Question 18

What is the number of CD4 cells in a person with HIV

Answer 18

less than 200

Question 19

What are the opportunistic diseases of HIV

Answer 19

TB and the common cold

Question 20

What is the treatment for HIV

Answer 20

ARVs (Anti-retrovirals)

Question 21

What do ARVs do

Answer 21

They stop viral replication and allow the immune system to recover

Question 22

Define viral-load

Answer 22

The amount of HIV in a persons blood

Question 23

What are opportunistic infections treated with

Answer 23

Antibiotics

Question 24

How does HIV spread

Answer 24

Through bodily fluids

Question 25

What does a locator protein do

Answer 25

finds CD4 cells

Question 26

What is a reverse transcriptase

Answer 26

an enzyme that tells RNA to go backwards

Question 27

What are the 4 stages of HIV

Answer 27

1) Acute infection
2) Asymptomatic phase
3) Symptomatic phase
4) Full blown aids

Question 28

What happens during the acute phase

Answer 28

Increase in viral load and decrease in CD4 cell count
-Flu like symptoms
-Infectious
-Negative HIV test

Question 29

What happens during the asymptomatic phase

Answer 29

No signs or signals of infection
-Viral load undetectable
-Infectious

Question 30

What happens during the symptomatic phase

Answer 30

Thrush, TB, bronchitis, fatigue
-CD4 count drops
-Risk of developing opportunistic diseases

Question 31

What does it mean if someone has full blown aids

Answer 31

Their CD4 cells are below 200

Question 32

What are the 4 stages of the reproduction of a virus

Answer 32

1. Adsorption
2. Penetration
3. Latent
4. Lysis

Question 33

What happens during the adsorption phase

Answer 33

The virus finds a host cell and attaches itself

Question 34

What happens during the Penetration phase

Answer 34

The virus ejects itself into the host cell

Question 35

What happens during the latent phase

Answer 35

The virus replicates inside of the host cell

Question 36

What happens during the lysis phase

Answer 36

The host cell wall tears and the replicated virus comes out

Question 37

During what stage of the preproduction cycle of a virus do symptoms start showing

Answer 37

Lysis phase