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50 terms

Microbiology Exam 2

When did the first evidence of multicellularity appear?
.5 billion years ago
When did the single cell stage in the evolution of life take place?
3.5 billions years ago
How many years of chemical change did it take for the cell to evolve on Earth?
1 billion years
What was the driving force for the step towards cells?
protecting RNA
What was a distinct advantage of confining organic molecules within a pre-cell?
a specific ribozyme can catalyze only a specific RNA
How can simple membranes be chemically produced?
subjecting a warm-water solution of amino acids to cool temperatures and mixing lipids and water.
When did the era of RNA occur in accordance with the era of life?
the era of RNA preceded the era of life
Ribozymes are _________ in their catalytic action than protein enzymes.
less specific
The evolution of microbial metabolism is directly linked with microbial _______.
Among the simpler microbes metabolic precesses involved relatively few genes that produced soluble enzymes, proteins, and _________.
three kinds of RNA
The first cells probably lived as _________.
The frist cells probably obtained energy by "eating" the organics that produced _______.
Fermentation takes place in an ________ environment.
In _______ a sugar molecule is broken down into pyruvic acid.
ATP is produced from ADP by the addition of _________ to _______.
phosphate, ADP
In some bacterial cells ____ is changed to ______ when respiration is prevented.
pyruvic acid, lactic acid
In other bacteria, under oxygen-poor conditions _________ is converted to _________.
pyruvic acid, CO2, and ethanol
Streptococcus and Lactobacillus are two major groups of bacteria that are ___________.
Nitrogen fixation is a process that makes available __________ to living organisms.
atmospheric nitrogen
Replenishing the atmosphere with nitrogen is accomplished through _________.
On of the first metabolic pathways considered a step towards autotrophy involves the conversion of ________ to ________.
sulfate, sulfide
_________ is the ATP producing pathway in nearly all eukaryotes.
oxygen respiration
The domain of life that contain few species of microorganisms is called ________.
The Earth surface is significantly heated from ________.
radioactive decay of elements
Microbes that evolved a chemical machinery to withstand extreme temperatures are considered ________.
An ozone layer is characteristic of _______.
secondary atmosphere
The biological species concept of bacteria is based on ________ and ________ grounds.
color, shape, phenotypic, genetic, size, and shape.
A ____% difference in the 16S rRNA is grounds for a new species designation in bacteria.
__________ bacteria rely on other organisms for their sustenance, __________ bacteria are microbes that gather their own food and energy from the environment.
heterotrophs, autotrophs.
Chemoautotrophic bacteria provide organic molecules to this deep sea invertebrate.
Botulism toxins stops the release of ________ for muscular contraction.
acetylcholine and molecular messenger
The two major groups of bacterial autotrophs involve bacteria that can utilize _______ and _______ to produce energy.
organic, inorganic compounds
An organelle in the cell of photosynthetic eukaryotes that is the site for photosynthesis is called ________.
a plastid
Rhizobium is an example of a ________.
prokaryote and nitrogen fixing bacteria.
The quantitative measure of pathogenicity is termed ________.
Mucous membranes are often coated with a protective layer of _______.
Most of the organisms living today are fundamentally similar in all but one of the following characteristics.
Oxygen was a _____ factor in the eventual evolution of higher metabolism.
A significant difference between the archaea and the bacteria is in the molecular composition of their _______.
cell membrane
Rod-shaped bacteria that are slightly bent are called _______.
Small cells have a _______ surface-to-volume ration than larger cells.
Gram-positive cell walls differ from Gram-negative cells walls in that the cell walls of Gram-positive bacteria contain _______.
teichoic acids
Protein molecules that lie on the surface of the cell membrane are called _________.
peripheral proteins
The process of transmembrane movement that involves a transporter is called ______.
facilitative diffusion
When a cell is in a medium that has a higher concentration of solutes than there is in the cell we say that the cell is in a _______ solution.
Redox reactions transfer _________.
energy, electrons, and involve oxidation and reduction.
A reduced molecule ________.
has gained electrons
Coenzymes are _____.
organic cofactors
Under the ideal conditions, the complete aerobic oxidation of one molecule of glucose by a bacterium allows a net gain of how many ATP molecules?
A vegetative cell is likely to be found in which one of the following microbes?
Bacillus and Chlostridium