Viruses

Question 1

Explain why virus are obligatory intracellular parasites

Answer 1

b/c they require living host in order to multiply

Question 2

Viruses are entities that;

Answer 2

1. contain single type of nucleic acid (DNA or RNA)
2. contain protein coat that surrounds nucleic acid
3. Multiply inside living cells by using the synthesizing machinery inside the cell
4. cause synthesis of specialized structures that can transfer viral nucleic acid to other cells

Question 3

what is a Virion

Answer 3

complete viral particle with nucleic acid and capsid. it lives outside of cell

Question 4

what is a bacteriophage

Answer 4

a virus that infects a bacteria cell

Question 5

list the 3 basic types of viral shapes

Answer 5

1. helical
2. polyhedral
3. complex

Question 6

Non-enveloped Viruses

Answer 6

surrounded by protein coating called Capsid which does job of attaching to host cells

Question 7

what is the function of a Capsid

Answer 7

use for attachment to host cells

Question 8

what is a virus host range

Answer 8

the spectrum of host cells a virus can infect

Question 9

what determines a virus host range

Answer 9

the virus requirements for its specific attachment to host cells and availability within host cell of cellular factors it requires to replicate

Question 10

what are the steps to viral multiplication and explain each step

Answer 10

1. Attachment: phage attaches to surfaces of host cell
2. Penetration: viral DNA enters host cell
3. biosynthesis: phage DNA replicates and phage proteins made
4. Maturation: new phage particles are assembled
5. Lysis: cell lysis and release newly made phages

Question 11

what is the lytic cycle in a virus

Answer 11

phage causes lysis and death of host cell

Question 12

what is lysogenic cycle in a virus

Answer 12

prophage DNA incorporated into host DNA