Immuno - Microbial Infection

Question 1

Why are viruses not cells in their own right and waht are they, if not cells?

Answer 1

Because they require a host cell to replicate.
Obligate parasites.

Question 2

Can viruses infect bacteria?

Answer 2

Yes

Question 3

List the main types of infectious agent causing disease in humans.

Answer 3

Viruses

Bacteria

Fungi

Protozoa

Helminths

Question 4

Describe how viruses replicate.

Answer 4

Host Cell Machinery

Divide by budding out of host cells, or cytolysis

Question 5

What makes HIV a retrovirus?

Answer 5

RNA used to make DNA via Reverse Transcriptase

Whereas normally in viruses DNA makes RNA which makes the protein

Question 6

Recall an example of a virus

Answer 6

Smallpox - variola virus

Question 7

What makes Prokaryotes more susceptible to the effects of a mutation?

Answer 7

They are haploid, so if one gene is mutated, the effect will occur

However in diploid cell, the mutation must be seen on both copies of DNA to occur

Question 8

What is the main component of Prokaryotic cell walls?

Answer 8

Peptidoglycan (murein)

Question 9

How do Prokaryotes divide?

Answer 9

Binary Fission

Question 10

What are the purpose of the pili (several pilus) on Prokaryotes?

Answer 10

They can have a role in movement, but are more often involved in adherence to surfaces, which facilitates infection, and is a key virulence characteristic

Question 11

Why are the mutation rates of viruses higher than humans?

Answer 11

They have half the point mutation rate as they have error prone replication and cannot deal with errors in genetic code efficiently

Much shorter replication times (20 mins vs 26 yrs)

Question 12

Based on the location of the infection, what three groups can Fungi be divided into?

Answer 12

Cutaneous - typically involving the skin, hair, and nails

Mucosal - oral, gastrointestinal, vaginal

Systemic Mycoses - affecting internal organs

Question 13

Which two forms can fungi exist in during their lifetimes?

Answer 13

Yeasts

Filaments

Question 14

How do Protozoa replicate?

Answer 14

Replicate in host by binary fission

Or by formation of trophozoites inside a cell

Question 15

How is Protozoa infection acquired?

Answer 15

Ingestion

Or through a vector

Question 16

What does metazoa mean?

Answer 16

Contains cells that are differentiated into tissues and organs

Question 17

What type of organism are helminths?

Answer 17

Multicellular and eukaryotic.