Block A Flashcards
Microbial diversity and ecology
What is the significance of microbiology in relation to the world?
Microbiology makes the world go around and every process on planet Earth is driven by microorganisms.
How does microbial diversity compare to that of macro-organisms?
Microbial diversity is far greater than that of macro-organisms.
What is phylogeny?
Phylogeny is the science of examining evolutionary relationships of a group of organisms.
What are traditional methods of studying microbial diversity based on?
Traditional taxonomy and systematics relied on morphology and biochemistry.
What is the role of gene sequences in phylogenetics?
Gene sequences are used to infer the relationship between species.
What is the 16S ribosomal RNA gene used for?
The 16S rRNA gene is widely used for phylogenetic studies due to its highly conserved nature.
What are the characteristics of a good phylogenetic marker gene?
- Orthologous
- Present in all species of interest
- Conserved with observable differences
- Evolves at a slow and steady rate.
What is LUCA?
LUCA is the Last Universal Common Ancestor of all living organisms.
What evidence suggests that cells appeared on Earth?
Evidence indicates cells appeared on Earth 3.8 to 3.9 billion years ago.
What type of atmosphere existed on Earth for the first 2 billion years?
An anoxic atmosphere with mainly N2 and CO2.
How did oxygenic phototrophic cyanobacteria evolve?
They evolved around 2.5 billion years ago from anoxic phototrophs.
What is the two-domain hypothesis?
The two-domain hypothesis posits that Eukaryotes belong to the same branch as the Archaea.
How many species of Eukaryotes are estimated to exist on Earth?
Approximately 8.7 million species.
What is the typical genome structure of bacteria and archaea?
Genomes are generally one single circular DNA molecule.
What is the genome of Escherichia coli characterized by?
Approximately 4.4 million base pairs and about 4,300 genes.
What is the coding density of genes in humans compared to E. coli?
Humans have about 10 genes/Mbp, while E. coli has about 1000 genes/Mbp.
What is a defining feature of bacterial genomes?
Bacterial genomes are naturally haploid and do not contain introns.
What is the definition of microbial diversity?
Microbial diversity refers to the vast variety of microorganisms present in various environments.
True or False: Viruses are considered part of the cellular tree of life.
False.
What is the role of metagenomics in studying microbial biodiversity?
Metagenomics is used to identify microbial biodiversity and has revealed a large number of novel lineages.
Fill in the blank: The first free-living organism to have its genome sequenced was _______.
Haemophilus influenzae.
What is the significance of the 16S rRNA gene in phylogenetics?
It provides a reliable molecular clock for studying phylogeny.
