The nature of infection

Question 1

What are the 4 fundamental divisions of life and describe them a little?

Answer 1

1. Bacteria (prokaryotes) - generally small, single celled
2. Archaea - single celled, similar to bacteria
3. Eukaryotes - includes protozoa (single celled animals) and fungi (higher plant like organisms)
4. Viruses - NON-LIVING, very small obligate parasites

Question 2

What are prions?

Answer 2

Prions are protein based infectious agents (non-living)

Question 3

Give 8 properties of Eukaryotes (fungi and protozoa)

Answer 3

1. Size 5 to 50 micrometres
2. Complex, compartmental structure
3. Frequently multi-cellular
4. Have linear chromosomes and histones
5. Contain introns and exons
6. Have no/flexible cell wall
7. Cell cycle (mitosis/meiosis)
8. Eukaryotic ribosomes are known as 80s ribosomes

Question 4

Give 8 propertied of Prokaryotes (bacteria)

Answer 4

1. Size 0.5 to 10 micrometres
2. Relatively simple
3. Often single celled
4. Single circular chromosome, additional “extrachromosomal” DNA is carried in plasmids
5. Introns are rare
6. They have rigid cell walls
7. They have a rapid cell cycle
8. Prokaryotic ribosomes are known as 70s ribosomes

Question 5

What is a nucleoid?

Answer 5

A nucleoid is an irregularly shaped region in a prokaryotic cell that contains most of the genetic material. It refers to not only the genetic material but all proteins associated with it. It is not the nucleus and has no membrane or defined location. The chromosomes in it are singe circular molecules and has primitive DNA segregation machinery