Answer both questions.
(a) This question is composed of six (6) parts, all of which are to be answered.
- (i) Why are 16S rRNAs thought to be the best molecules for undertaking phylogenetic
studies ?
- (ii) What major evolutionary findings have emerged from the study of 16S rRNA
sequences ?
- (iii) Describe and discuss the methods that have been used for studying 16S rRNA
as a phylogenetic tool.
- (iv) What is phylogenetic staining ?
- (v) What are signature sequences and of what phylogenetic value are they ?
- (vi) Describe and discuss the structure of 16S rRNA with respect to their functions
in a bacterial cell.
(b) This question is composed of four (4) parts, all of which are to be answered.
- (i) The anatomical and physiological features of the gastrointestinal tract of humans
are different to that of the rumen of ruminants. Describe the ways by which they influence
the microbial populations.
- (ii) Discuss the host-microbe relationship that exists in the gastrointestinal tracts
and the rumen. How does this relationshipdiffer from that observed in hydrothermal vent
animal communities ?
- (iii) Discuss the prospects and constraints of establishing genetically engineered
microbes in the rumen.
- (iv) "Microbes in the gastrointestinal tracts of humans are under constraints."
Explain what these constraints are citing examples.
(46 marks)
Question 2
Write notes on and/or draw schematic diagrams for all nine (9) of the following
(a) Dental plaque, cavities and periodontal disease
(b) Archael nutrition
(c) Skin microflora
(d) Synergism
(e) Nitrogen cycling
(f) Probing for microbes in the environment
(g) Microbial community structure
(h) Soil microflora
(i) Microbial leaching of minerals
(54 marks)
Question Three
Write an essay on the comparative biology of the Archea, with reference to the Bacteria
and Eucarya.
(30 marks)
Question Four
Write notes on all three (3) of the following:
(a) The role of the Entner - Doudorof Pathway in the Archaea. In particular outlining the
Atwo alternative variations of this pathway that have been indentified in the organisms.
(b) Energy production in the Methanogens.
(c) The role of the citric acid cycle enzymes in the metabolism of the Archaea.
(30 marks)
