Chapter 18 NOTES

Question 1

What are viruses

Answer 1

Acellular collections of biomolecules that infect cells

Question 2

What are viruses usually associated with?

Answer 2

Plant, animal, and human diseases

Question 3

Why are viruses considered non-living

Answer 3

Because they don’t exhibit all of the criteria of life

Question 4

True or False: Viruses are extremely small and non-cellular

Answer 4

True

Question 5

True or False: Viruses have a DNA and RNA genome

Answer 5

True

Question 6

True or False: Viruses range from having 4-50 genomes in size

Answer 6

False; 4-100

Question 7

Each virus always has two parts, and can occasionally have an additional part. What are these parts?

Answer 7

Always: Capsid and Nucleic Acid
Occasionally: Envelope

Question 8

True or False: Viruses can vary in shape from thread like rods to polyhedral to complex “space probes”

Answer 8

True

Question 9

How do viruses gain entry into specific host cells?

Answer 9

The capsid adheres to the specific receptor sites on the host cells surface

Question 10

For most of the time, viruses have narrow host ranges; meaning that they can only enter one specific _____, or even one specific _____.

Answer 10

Species, Tissue

Question 11

True or False: Viruses rely on cells proteins in order for them to replicate

Answer 11

False: Viruses rely on the host cells enzymes, ribosomes, and ATP for its own replication

Question 12

What are Bacteriophages

Answer 12

Viruses that infect PROKARYOTIC (bacteria) CELLS

Question 13

During the process of a Bacteriophage entering the cell, what will FIRST enter the cell

Answer 13

Nucleic Acid

Question 14

Once the nucleic acid of the bacteriophage is inside the cell, the virus takes over___________ of the host cell

Answer 14

Metabolic Machinery

Question 15

What are the five stages that the lytic cycle is divided into

Answer 15

1. Attachment
2. Penetration
3. Biosynthesis
4. Maturation
5. Release

Question 16

What happens to Phage DNA in the Lysogenic Cycle?

Answer 16

The Phage DNA becomes a Prophage

Question 17

Where does the virus become integrated into during the lysogenic cycle?

Answer 17

Into the host cells DNA

Question 18

What are Retroviruses

Answer 18

RNA animal viruses that have a DNA stage

Question 19

What enzymes do retroviruses carry?

Answer 19

Reverse Transcriptase

Question 20

What does reverse transcriptase do

Answer 20

Copies RNA into a double-stranded DNA that gets integrated into the host genome

Question 21

Compare the Normal way to the Retro virus way

Answer 21

DNA -> RNA-> Protein= Normal
RNA-> DNA-> Protein= Retrovirus way

Question 22

What are Viroid’s

Answer 22

Un-capsulated (non-capsid) RNA strands

Question 23

What induces the cell to produce more viroid’s

Answer 23

Viroid’s

Question 24

What are Prions

Answer 24

Proteins that change their shape in a biochemical response to contact