Viruses

Question 1

What are viruses? Are viruses cells

Are they alive

Can they reproduce?

Answer 1

no
very small infectious particles

viruses cannot reproduce on their own. They invade others

Only with a host, we say they have a borrowed life

Question 2

Structure of a virus

What is the capsid

What is a Bacteriophage

Characteristic shape?

Answer 2

2 types
DNA or RNA, enclosed in a protein coat

Made from capsomeres
sometimes membranous envelope with glycoproteins

and, in some cases, a membranous envelope with
glycoproteins e.g. Influenza or Covid

E.g E.coli infected
*Viruses that infect bacteria

DNA
Capsid
*Characteristic shape -protein head, tail, fiber(s) to attach themselves to the host
*Phages are the best understood of all viruses

Question 3

Reproductive cycle of virus

List what the virus makes use of from the host’s cell

When the virus leaved the host cell, what happens to it?

Answer 3

1. Entry - proteins separate from genetic material
2. Replication- using host cells resources e.g enzymes tp make more DNA or RNA
3. Transcription and manufacture of capsid-
   DNA as a template
   Transcribed into MRA
   MRA is translated into a sequence of Amino acids

Self-Assembly of new virus and DNA and AA come together and the mature virus leave the cell

ribosomes, enzymes, tRNA, AA, energy,

usually destroyed

Question 4

Viral Diseases in plants cause

Viral Diseases in Animals

Answer 4

spots on leaves
spots in fruits
stunted growth
damages flowers and roots\

HIV (virus)- Aids (causes)
Ebola Virus- hemorrhagic fever
West Nile Virus- encephalitis
Influenza Virus
Spanish FLu Epidemic was caused by type A
H1N1-

Corona Viruses
Cause SARS
MERS
COVID 19 (

Question 5

Emerging Viruses *term applied to a newly discovered virus, one that is increasing in incidence or with the potential to increase in incidence.

*THREE processes contribute to the emergence of viral diseases

Answer 5

–The mutation of existing viruses,
which is especially high in RNA viruses

–Dissemination of a viral disease from a small, isolated human population, allowing the disease to go unnoticed before it begins to spread

–Spread of existing viruses from animal populations; about three-quarters of new human diseases originate this way

Question 6

Vaccines

Answer 6

A vaccine is a harmless variant or derivative of a
pathogen that stimulates the immune system to build
defenses against the harmful pathogen.

you get a form of the virus, but not as potent