Wk1: Microbial Phylogeny

Question 1

Why is the robosomal small subunit used? (16S RNA)

Answer 1

• SSU RNA contains sufficient sequence information from its variable (to measure long evolutionary relationships) and invariable regions (measure close evolutionary relationships) which allows for comparison between homologues.
• Highly conserved - doesn’t change much in the phylogenetic tree, and all organisms contain the ribosomal SSU

Question 2

What are phylogenetic trees useful for?

Answer 2

Useful for representing evolutionary distances between microorganisms

Question 3

What are the 5 bacterial phyla explained in this course?

Answer 3

Proteobacteria, Firmicutes, Tenericutes, Planctomycetes, Thermotgae and Aquificae

Question 4

What are characteristics of the proteobacteria?

Answer 4

Largest phylum of bacteria, gram negative, morphologically and metabolically diverse. Categorised into sub groups called alphaproteabacteria, gammaproteabacteria

Question 5

What are the characteristics of Firmicutes?

Answer 5

Gram positive bacteria, have low C+C genomes, many medically and industrial important species

Question 6

What are the characteristics of tenericutes?

Answer 6

Gram positive, but don’t have a cell wall

Question 7

What are the characteristics of planctomycetes?

Answer 7

Gram positive (cell wall lacks peptidoglycan), contain membrane bound compartments even though its a prokaryote

Question 8

What are the characteristics of thermotogae and aquificae?

Answer 8

Thermophilic bacteria,