Chapter 15: Microbial Numbers & Identification Flashcards
What type of culture is used to promote growth of desired microbes over undesired cells?
Enrichment methods
How many times more prokaryotic cells than human cells are in the human body?
10 times
What type of column is used to illustrate enrichment?
Winogradsky column
What do the different areas of a Winogradsky column correlate to?
Nutritional microenvironments
What type of cultivation-independent method is used on extracted and PCR-amplified environmental DNA fractions?
Direct sequencing
What type of cultivation-independent method separates DNA from an environmental sample following fragmentation (restriction endonuclease)?
Denaturing gradient gel electrophoresis (DGGE)
What type of cultivation-independent method can illustrate larger-scale differences in DNA sequences without identifying each base?
Denaturing gradient gel electrophoresis (DGGE)
What type of culture-independent method uses labeled oligonucleotide probes to bind to specific DNA/RNA in a mixed population of cells?
Fluorescent in situ hybridization (FISH)
What type of culture-independent method works by detection of labeled cells in a mixed population by passing them through a laser and detecting light?
Flow cytometry
What type of culture-independent method uses DNA from an environmental sample to construct a genomic library?
Metagenomics
What type of culture-independent method uses genes from a community library to identify, screen, and compare to other areas?
Metagenomics
What term describes the number of species in an ecosystem?
Diversity
What term defines a prokaryotic “species”?
Operational Taxonomic Unit (OTU)
What must be 97% similar for a group of organisms to be defined as a species?
rRNA gene sequence
