Week 5
The site on the DNA to which a repressor protein binds is the __________.
operator
This operon, which metabolizes lactose, is typically on when lactose is present.
What is the Lac operon?
This is the transfer of bacterial genes by viruses, such as a bacteriophage mistakenly packaging a fragment of host DNA.
What is transduction?
This symbiotic relationship is usually obligatory and results in both partners benefiting.
What is mutualism?
The base pairing between _____is especially strong because it contains an additional ____ bond, compared to _____.
a.A and T / ionic / C and G
b.A and T / hydrogen / C and G
c.C and G / ionic / A and T
d.C and G / hydrogen / A and T
d.C and G / hydrogen / A and T
This term describes how glucose can be used preferentially as the carbon source, but lactose will be used if glucose runs out or is low.
What is catabolite repression?
Name an example of an induced mutation caused by UV radiation.
What are thymine dimers?
Organisms that obtain energy from the oxidation of chemical compounds (inorganic or organic) and electrons from organic sources are in this category
What are chemoorganotrophs?
This sequence on the mRNA binds to the 16S RNA of the small ribosomal subunit to initiate bacterial translation.
What is the Shine-Dalgarno sequence?
This protein, which acts as a helicase, is responsible for factor-dependent termination of transcription in bacteria.
What are mutations resulting from DNA or genetic errors, like mispairing due to tautomerization or errors in DNA replication, called?
What are spontaneous mutations?
This is the location where a river meets the sea, and microbes here are often halotolerant.
What is an estuary?
Describe the role of DNA vs RNA polymerase.
makes DNA from DNA template vs
makes RNA from DNA template
What is the response to environmental stress that involves the synthesis of the second messenger pppGpp to decrease RNA production?
What are cells called when the F (fertility) factor is integrated into the bacterial chromosome rather than existing as an autonomous plasmid?
What is an Hfr cell (High-Frequency Recombination cell)?
Differentiate lotic vs lentic systems.
Free running vs free standing waters
These are the three functional segments of a ribosome involved in translation.
What are the A,P, and E sites?
Describe four global regulation systems.
*answers can vary, check review slides
The mismatch repair system is a post-replication repair mechanism where enzymes scan for and remove mismatched pairs; this protein is responsible for destroying a repressor in the SOS response.
What is RecA?
What is the term for the observation that fewer than 5% of microbial cells observed in an environmental sample via microscopic examination can be successfully grown and form colonies when cultivated on a standard laboratory agar plate, and name two contributing factors?
Great Plate Count Anomaly
Slow growing
Low abundance
Inhibition by other microbes in a mixed culture
Fastidious growth requirements
Cross-feeding or communication signals from other microbes are needed
Lack triggers for growth or exit from a dormant state