Virology

Question 1

virus is

Answer 1

an obligate intracellular parasite, capable of replication only within the living cells its an inert particle , they can not perform processes for energy or biosynthesis

Question 2

virus outside a host cell

Answer 2

inert , no enzymes or other activity

Question 3

inside a host cell

Answer 3

viral nucleic ( DNA OR RNA ) takes over the cell and directs it to produce a new virus particles ( replication )

Question 4

virus size

Answer 4

range from 20 to 450 nm
can be seen by electron microscope

Question 5

reasons for studying viruses

Answer 5

1- are important agents of many human diseases
2 sources of enzymes
3 gene vector for protein production & treatment of genetic diseases
4 production of vaccines
5 how anti viral drug work

Question 6

virus structure

Answer 6

nucleic acid
lipid envelope
protein capsid
spike protein
polymerase

Question 7

virion

Answer 7

complete intact particle in the extracellular phase

Question 8

viral genome

Answer 8

is composed of single nucleic acid DNA OR RNA can be ds or ss , linear or circula , containing several segments or one molecule ss NA can have + 5 to 3
- 3 to 5

Question 9

capsid

Answer 9

virus coded protein surrounds the NA determine its antigenicity

Question 10

viral envelope

Answer 10

it surrounds the nucleocapsid and composed of virus specific proteins plus lipids and carbohydrate derived from the cell host membrane

Question 11

classification of viruses

Answer 11

1. genome type
2. size
3. presence of enzymes
4. host tissue or cell tropism
5. type of host

Question 12

genome type

Answer 12

DNA OR RNA
strategy of replication

Question 13

size and morphology

Answer 13

type of capsid
no of capsomers
presence or absence of envelope

Question 14

host tissue or cell tropism

Answer 14

reverse transcriptase ( retroviruses e.g. HIV )

Question 15

type of host

Answer 15

bacteriophage
plant
animal

Question 16

how viruses named

Answer 16

diseases
cytopathology
site of isolation
places or people they discovered
biochemical

Question 17

viral replication steps

Answer 17

attachment penetration uncoating multiplication assembly release

Question 18

attachment

Answer 18

viral proteins on the capsid or phospholipid surface

Question 19

penetration

Answer 19

the process of attachment to a specific receptor can induce conformational changes in viral capsid protein or lipid envelope results in fusion of viral and cellular membrane / receptor mediated endocytosis

Question 20

uncoating

Answer 20

its the removal of and degradation of the viral capsid by enzymes releasing the vial genomic nucleic acid inside the host cell this makes it accessible to cellular transcription and translation machinery to from a new progency virions

Question 21

replication

Answer 21

synthesis for nucleic and proteins and the differ between DNA and RNA viruses and viruses with opposite nucleic acid polarity

Question 22

when viruses infect cell events

Answer 22

1 production of viruses enzymes and structure proteins
2 replication of viral genome

Question 23

the viral nucleic acid genome is

Answer 23

the genetic code

Question 24

the viral genomes must make.______that can be read by host _______

Answer 24

mRNA
cellular ribosomes

Question 25

early mRNA

Answer 25

transcribed from input parental virus genome

Question 26

late mRNA

Answer 26

transcribed from newly replicated viral genome

Question 27

early mRNA genes

Answer 27

code for activation and regulatory proteins enzymes

Question 28

late mRNA genes

Answer 28

code for structural proteins capsid