Virus

Question 1

what is regressive evolution

Answer 1

viruses become degenerated from previous independent life forms.
lost many function, and is retained only when needed for parasitic lifestyle.

Question 2

How many viruses are able to infect humans ?

Answer 2

219

Question 3

Define a virus

Answer 3

A virus is a small, non-living infectious particle that consist of a nucleic acid, and capsid and is not able to metabolise, reproduce, or grow without the aid of an host

Question 4

what is the size of human red blood cell

Answer 4

10,000nm in diameter

Question 5

what is the size of bacteriophage T4 ?

Answer 5

225nm

Question 6

what is the size of Adenovirus ?

Answer 6

90 nm

Question 7

size of E.coli ?

Answer 7

3000 * 1000 nm

Question 8

using Baltimore classification, name the 7 classes of virus

Answer 8

dsDNA (class 1) - papilloma virus, herpes virus, adenovirus
ssDNA (2)- Adeno associated virus
dsRNA (3)- Riovirus
+ssRNA (4)- polo virus, foot and mouth virus, hepatitis A and c
-ssRNA (5)- influenza
ssRNA-RT (6)- HIV
dsDNA-RT (7) - hepatitis B

Question 9

what are the types of viral tropism

Answer 9

tissue tropism
cell tropism
host tropism

Question 10

describe the molecular mechanism of virus entry

Answer 10

adsorption- virus first attaches to cell receptor using their spikes by specific binding

penetration- virus becomes engulfed by vesicle via endocytosis
the envelop of the virus is removed and RNA is released freely into the cytoplasm

synthesis- replication and protein synthesis takes. under the control of the viral gene, new components of the virus is formed, ie, capsomers, RNA molecules and spikes

assembly - viral spike proteins are inserted into the cell membrane for viral envelope, nucleocapsids is formed from RNA and capsomers

Release- envelop viruses buds off the membrane, carrying away an envelop with spikes. this complete virus is ready to infect another cell

Question 11

what is test is used for the DIRECT examination of :
virus particles
viral antigen
viral nucleic acid

Answer 11

electron microscope
ELISA test
PCR- polymerase chain reaction
respectively

Question 12

which antibody is produced shorted after infection ?

Answer 12

immunoglobulin M (IgM) antibody

Question 13

which antibody is made a few days after infection ?

Answer 13

Immunoglobulin G (IgG )

Question 14

what is serology ?

Answer 14

this is the scientific study of serum or plasma especially in regards to the bodies immune system response.

Question 15

List the steps of PCR and respective temperature required

Answer 15

denaturation- 90 degree
Annealing- 50-60 degree
Denaturation- 75 degree
exponential growth of product