Exam 3 Flashcards
In anoxygenic photosynthesis, which compound (or compounds) is (are) used by purple and green bacteria as a source of electrons for the reduction of CO2?
H2S
In an ecological sense, the variety of photosynthetic pigments found among different groups of photosynthetic bacteria allows them to:
avoid direct competition by absorbing different wavelengths of light
Spirochetes that are known human pathogens include:
Two or more are correct (vibrio cholera and borrelia burgdorferi)
Rickettsias and chlamydias are two unrelated groups of bacteria that nevertheless share a unique characteristic. This characteristic is:
they are both obligate intracellular parasites of eukaryotes
As discussed in lecture, which of the following bacteria are aerobic chemolithotrophs?
Nitrobacter
What important soil process are these chemolithotrophic bacteria (nitrobacter) involved in?
nitrification
The hypothesis has been proposed that magnetotactic bacteria sense the Earth’s magnetic field in order to:
swim in the direction of a microaerophilic environment
What evidence suggests that cyanobacteria-like ancestors were present on the Earth as early as 3.5 billion years ago?
fossilized stromatolites
Many of the magnetotactic bacteria are found among the:
spirilla
In lecture, Hyphomicrobium was given as an example of a:
budding bacterium
The currently accepted division of all living organisms on Earth into three domains is based on differences in what fundamental characteristic?
small-subunit ribosomal RNA sequences
Current estimates are that _______ of the microorganisms in a typical environmental sample, such as soil or water, have been cultivated before in the laboratory.
less than 1%
From your reading in the textbook, metagenomics refers to:
using modern genomic techniques to study entire microbial communities directly in their natural environments.
From your reading in the textbook, enzymes that are used in the laboratory to recognize and cleave DNA molecules at very specific base sequences, often for the purpose of cloning, are called:
restriction endonucleases
One general characteristic of gene transfer processes in bacteria is:
Gene transfer is always unidirectional (from donor to recipient)
A mutation occurs in the lac operon of E. coli. You observe that the mutant is unable to bring lactose into the cell. Which gene(s) in the operon has (have) been mutated?
lacY