microorganisms
The largest mass of living material on Earth comes from
metabolism, growth, and evolution
Like all forms of life on Earth, all microbial cells perform three major types of activities: __________.
analysis of ribosomal RNA
Explain how organisms are placed into the three major cell lineages or domains.
b.Microbial cells include both bacteria and viruses.
Which of the following statements is FALSE?
a.Microbial cells exclude the cells of plants and animals.
b.Microbial cells include both bacteria and viruses.
c.Microbial cells exist as single cells.
d.Microbial cells carry out their life processes of growth independently.
a.Microbial cells exclude the cells of plants and animals.
b.Microbial cells include both bacteria and viruses.
c.Microbial cells exist as single cells.
d.Microbial cells carry out their life processes of growth independently.
b.Microbial communities are assemblages of populations
Which statement is TRUE?
a.Populations are assemblages of microbial communities.
b. Microbial communities are assemblages of populations.
c. Habitats are assemblages of microbial communities.
d. Populations are assemblages of habitats.
a.Populations are assemblages of microbial communities.
b. Microbial communities are assemblages of populations.
c. Habitats are assemblages of microbial communities.
d. Populations are assemblages of habitats.
cell wall.
The structure that confers structural strength on the cell is known as the
amino acids, carbohydrates, lipids, and nucleic acids.
Major classes of macromolecules present in all living microorganisms include
ribosomal RNA
All life on Earth can be divided into three main Domains, the Bacteria, the Archaea, and the Eukarya, based on the similarities of their __________.
anaerobes, anoxygenic phototrophs, oxygenic phototrophs, aerobes, multicellular organisms
Arrange the types of microorganism in the order they evolved on Earth.
Archaea, Bacteria, and Eukarya
In what/which domain(s) of life is/are microorganisms represented?
microbial life existed for billions of years before plant and animal life.
Regarding early life on Earth,
in the oceanic and terrestrial subsurfaces.
Most prokaryotic cells reside
They lack ribosomal RNA.
Deduce why viruses are excluded from the ribosomal RNA-based tree of life.
living organisms / their chemical and physical environments
An ecosystem includes ________ along with ________.
mold / Robert Hooke
The first documented description of a microorganism was of a ________ by ________.
Biology was primarily an observational science for many hundreds of years until the acceptance of the scientific method.
Hypothesize the most plausible reason why scientists accepted spontaneous generation for so many years.
d. developed enrichment culture techniques
Which of the following is NOT an accomplishment of Louis Pasteur?
a.developed heat sterilization techniques that involved the creation of a specialized swan-necked flask
b.developed the first rabies vaccine and treated thousands of individuals
c.determined that the alcohol-making process was mediated by microbial fermentation and thus refuted the theory of spontaneous generation
d.developed enrichment culture techniques
a.developed heat sterilization techniques that involved the creation of a specialized swan-necked flask
b.developed the first rabies vaccine and treated thousands of individuals
c.determined that the alcohol-making process was mediated by microbial fermentation and thus refuted the theory of spontaneous generation
d.developed enrichment culture techniques
kill all microbes in or on objects.
Microbial sterilization is used to
cells from a pure culture of the suspected pathogen must cause the disease in a healthy susceptible animal
The step in Koch’s postulates that most critically enabled him to determine that a particular microbe was the cause, and not an effect, of a particular disease was __________.
Some microorganisms can cause disease.
Explain the germ theory of disease
pathogen present in all cases of disease; pathogen isolated in pure culture; pathogen able to infect healthy host; pathogen re-isolated
Arrange Koch’s postulates in the correct order
is a population of identical cells.
A pure culture
resolution
A student observed a stained specimen of bacteria using bright-field microscopy. At 100x magnification, there appeared to be only one cell in the field of view, but at 1000x it was clear that there were two cells close together. The ability to distinguish these two cells as separate entities is called __________.
gram-negative / pink
You are given an electron micrograph of a bacterial cell. In the micrograph you can clearly see three thin layers of different densities surrounding the cell. Based on the micrograph, you can infer that this cell is ________ and would appear ________ after application of the Gram stain procedure.
peptidoglycan
In gram-positive Bacteria, the cell walls are composed mainly of thick ________ layers.
gram-positive Bacteria.
The peptide interbridge crosslinking between peptidoglycan layers is found ONLY in the cell walls of
differential
Staining increases the visible contrast of cells compared with the background. Because the Gram stain results in some types of bacteria staining purple, and other types appearing pink, this is called a __________ stain.
to increase the contrast and make the cells more visible
Specify why is it necessary to use stains to view microorganisms.
phase-contrast microscopy
Which of the following types of microscopy can be used with live cells?
sterols / hopanoids
Eukaryotes have ________ in their cytoplasmic membranes, which serve to strengthen and stabilize the membrane and make it less flexible. Many bacteria have similar molecules, known as ________, in their cytoplasmic membranes that have a similar role.
the ABC transport system.
The prokaryotic transport system that involves a substrate-binding protein, a membrane-integrated transporter, and an ATP-hydrolyzing protein is
breaches of the cell wall and cell lysis due to osmotic swelling
The enzyme lysozyme kills bacterial cells by cleaving the ï¢ï€1,4-glycosidic bonds in the peptidoglycan. This leads to which of the following?
teichoic acids — gram-positive
The presence of which of the components listed below would allow you to distinguish between a gram-positive or gram-negative cell wall?
The cells of the new unknown microorganism may be too small to see with the objective and ocular lenses you used.
You have discovered a new microorganism, but you want to know if it is a eukaryote or a prokaryote. To investigate this question you prepare a slide with a simple stain and view it with a light microscope with a 40X objective lens and 10X ocular lens. You also prepare a control slide using Saccharomyces cerevisiae (a unicellular eukaryote). You can see the cells on your control slide, but you don’t see cells when you look at your unknown microorganism. What can you conclude from this experiment?
gram-negative Bacteria.
The lipopolysaccharide (LPS) layer is found ONLY in the cell walls of
lipopolysaccharides.
Some of the intestinal symptoms elicited by pathogens such as Salmonella, Shigella, and Escherichia are due to the presence of
confer buoyancy on cells by decreasing their density.
A major function of prokaryotic gas vesicles is to
biological building blocks (e.g., amino acids, sugars, and nucleosides), then RNA (including catalytic and self-replicating RNA), then protein synthesis, then DNA, then lipid bilayers surrounding early cellular life
According to the RNA world hypothesis, which of the following was the correct sequence of developments?
RNAs can have catalytic activity.
What is one piece of evidence that supports the RNA world hypothesis?
the last organism prior to the divergence of bacteria and archaea
What was the LUCA?
Prokaryotes capable of cellular respiration and prokaryotes capable of photosynthesis took up residence in larger prokaryotes, forming obligate mutualisms. The prokaryotes capable of cellular respiration evolved into mitochondria and the prokaryotes capable of photosynthesis evolved into chloroplasts.
Which of the following best explains the endosymbiont hypothesis?
mitochondrion / chloroplast
Two eukaryotic organelles that are hypothesized to be the result of endosymbiosis are the ________ and the ________.
All the organisms are gram-negative.
Alphaproteobacteria can be distinguished by which of the following characteristics?
Proteobacteria
Which phylum harbors the MOST functional diversity observed and also has the MOST cultured representatives?
diverse microorganisms that inhabit almost every environment on Earth, including the colon of humans and other mammals
The Archaea are
RNA.
The first catalytic and self-replication biological molecule was most likely
ozone / UV radiation
As oxygen appeared in the atmosphere, ________ also accumulated, which formed a protective barrier that protects the Earth from ________.
Aerobic cellular respiration involves an electron transport chain with oxygen as the terminal electron acceptor. This produces large amounts of ATP as the electron transport chain produces the greatest amount of ATP in cellular respiration.
Why would it be highly advantageous to a cell to form a mutualism with a prokaryote capable of aerobic cellular respiration?
b. Mitochondria have a membrane that includes peptidoglycan.
Which of the following is NOT evidence that mitochondria originated as independent prokaryotes, as stated by the endosymbiont hypothesis?
a.Mitochondria have circular DNA that resembles that of prokaryotes.
b.Mitochondria have a membrane that includes peptidoglycan.
c.Mitochondria have ribosomes that are the same size as prokaryotic ribosomes.
d.Phylogenetic analyses place mitochondrial ribosomal RNA sequences within a bacterial phylum.
a.Mitochondria have circular DNA that resembles that of prokaryotes.
b.Mitochondria have a membrane that includes peptidoglycan.
c.Mitochondria have ribosomes that are the same size as prokaryotic ribosomes.
d.Phylogenetic analyses place mitochondrial ribosomal RNA sequences within a bacterial phylum.
Chloroplasts and mitochondria have a double-stranded, circular piece of DNA in their cytoplasm.
Which statements describe the evidence that supports the endosymbiotic theory?
biological building blocks (e.g., amino acids, sugars, and nucleosides), then RNA (including catalytic and self-replicating RNA), then protein synthesis, then DNA, then lipid bilayers surrounding early cellular life
According to the RNA world hypothesis, which of the following was the correct sequence of developments?
RNAs can have catalytic activity
What is one piece of evidence that supports the RNA world hypothesis?
Mitochondria have a membrane that includes peptidoglycan.
Which of the following is NOT evidence that mitochondria originated as independent prokaryotes, as stated by the endosymbiont hypothesis?
Chloroplasts and mitochondria have a double-stranded, circular piece of DNA in their cytoplasm
Which statements describe the evidence that supports the endosymbiotic theory?
a. The chloroplast arose from the incorporation of a cyanobacterial-like organism.
Which statement most closely expresses our present understanding?
a.The chloroplast arose from the incorporation of a cyanobacterial-like organism.
b.The chloroplast is an ancestor of the cyanobacteria.
c.The chloroplast and the cyanobacteria are not closely (or specifically) related.
d.The cyanobacteria are descendents of the chloroplast.
a.The chloroplast arose from the incorporation of a cyanobacterial-like organism.
b.The chloroplast is an ancestor of the cyanobacteria.
c.The chloroplast and the cyanobacteria are not closely (or specifically) related.
d.The cyanobacteria are descendents of the chloroplast.
these genes are of adequate length to show deep relationships
The genes for 16S rRNA are used to determine genetic relatedness because __________.
complicates the construction of phylogenetic trees and the interpretation of specific traits in relation to evolution.
Horizontal gene transfer
highly conserved and universally distributed
What characteristics make a gene a good candidate for determining the evolutionary relationships between organisms?
d.The current universal tree of life is based on molecular sequences and completely changes our view of evolutionary relationships between eukaryotic species.
Which of the following statements is FALSE concerning the universal tree of life?
a.Previous versions of the universal tree of life were based largely on fossils and comparative biology, which overlooked the diversity of and relationships between most prokaryotes.
b.The current universal tree of life is supported by multiple genes including SSU rRNA sequences.
c. The current universal tree of life depicts three domains of life, two of which are prokaryotic.
d. The current universal tree of life is based on molecular sequences and completely changes our view of evolutionary relationships between eukaryotic species.
a.Previous versions of the universal tree of life were based largely on fossils and comparative biology, which overlooked the diversity of and relationships between most prokaryotes.
b.The current universal tree of life is supported by multiple genes including SSU rRNA sequences.
c. The current universal tree of life depicts three domains of life, two of which are prokaryotic.
d. The current universal tree of life is based on molecular sequences and completely changes our view of evolutionary relationships between eukaryotic species.
phylogeny / nucleotide sequence data
The evolutionary history of a group of organisms is called its ________ and it is inferred from ________.
analyzing molecular similarities and then using computer algorithms or optimality criteria to construct phylogenetic trees showing hypothesized evolutionary relationships
Phylogenetic trees for bacteria are constructed by
SSU rRNA
The most widely used molecule in sequence-based evolutionary analyses are ________ genes.
descended from one ancestor.
A monophyletic group is a group that
Nucleotide changes accumulate in a sequence in proportion to time.
Which of the following is an assumption used in the molecular clock approach?
random.
A key concept in evolution is that all mutations are
be genetically and phenotypically cohesive
For organisms to be considered members of the same species, they must __________.
phenotypic, genotypic, and phylogenetic methods.
Polyphasic taxonomy uses methods that include
strains or species.
Because DNA:DNA hybridization reveals subtle differences in genes, it is useful for differentiating organisms from different
classified as individual strains of the same species.
You are studying 12 new isolates from the human skin. The isolates have 16S rRNA sequences that are 97% similar and share important phenotypic traits. Their genomes have 55% of their genes in common. The isolates would most likely be
systematics / taxonomy
Microbial ________ studies the diversity of microorganisms and links their phylogeny with ________.
function only in a limited set of enzymes and cofactors
Trace elements are found in bacterial cells in very small amounts because they __________.
growth factors
Organic micronutrients are commonly called __________.
both organic and inorganic compounds
Based on the functional roles of phosphate in various microbial metabolisms, deduce which compounds phosphate exists as in microorganisms.
phosphorus, selenium, and sulfur.
All microorganisms require
proteins.
The class of macromolecules in microorganisms that contributes MOST to biomass is
oxygen.
In aerobic respiration, the final electron acceptor is
glucose
Which of the following would NOT be required to grow an autotroph?
You only want to determine the cell wall type, not any biochemical characteristics.
Explain why you would use selective media instead of differential media to grow an organism.
a series of practices to avoid contamination.
Aseptic technique refers to
complex / minimal
To ensure growth of a newly discovered bacterium with unknown nutritional requirements, it would be best to begin with a ________ medium rather than a ________ medium.
is given off as heat.
In metabolism, energy that is not used
anabolism.
The reactions involved in producing larger compounds from smaller compounds is called
Catabolic reactions
Where does the energy required for anabolic reactions come from?
is an example of anabolism.
The use of amino acids to make proteins
lipids.
Lipases break down
is an example of anabolism.
The Pentose Phosphate Pathway
is a catabolic process.
oxidative phosphorylation
can either be anabolic or catabolic.
According to the animation, the reactions that occur between glucose and pyruvic acid
C2H3O2 (organic molecule)
Which of the following would be used by a chemoorganotroph for energy?
acetate, succinate, and glucose.
For a carbon source, chemoorganotrophs generally use compounds such as
two pyruvates; 2 NADH; 4 ATP
Applying your knowledge of metabolism, glycolysis starts with one molecule of glucose (6C) and produces a total of __________.
glycolysis.
The Embden-Meyerhof-Parnas pathway is another name for
2.
The net gain of ATP per molecule of glucose fermented is
oxidative phosphorylation yields a lot of ATP.
Fermentation has a relatively low ATP yield compared to aerobic respiration because
c. It is an alternative way to return electron carriers to their oxidized state.
Which of the following statements about fermentation is true?
a.It provides additional protons to allow the electron transport chain to continue.
b.It allows the electron transport chain to continue in the absence of oxygen.
c. It is an alternative way to return electron carriers to their oxidized state.
d. It is an alternative way for a cell to produce oxygen.
a.It provides additional protons to allow the electron transport chain to continue.
b.It allows the electron transport chain to continue in the absence of oxygen.
c. It is an alternative way to return electron carriers to their oxidized state.
d. It is an alternative way for a cell to produce oxygen.
It takes the electrons from NADH, oxidizing it back into NAD+.
What is the role of pyruvic acid in fermentation?
It returns to glycolysis to pick up more electrons
What is the fate of the NAD+ newly regenerated by fermentation?
b. Lactic acid and propionic acid
Which of the following is an acid produced by fermentation?
a. Propionic acid
b. Lactic acid and propionic acid
c. Lactic acid
d.Pyruvic acid
e. Ethanol
a. Propionic acid
b. Lactic acid and propionic acid
c. Lactic acid
d.Pyruvic acid
e. Ethanol
Acetaldehyde
What is the intermediate product formed by pyruvic acid during alcoholic fermentation?
Fermentation forms organic acids and takes place in the absence of oxygen, while respiration forms water and carbon dioxide in the presence of oxygen
Distinguish how fermentation and respiration differ.
the difference in charge across the plasma membrane with protons outside the membrane and electrons inside the membrane
The proton motive force (PMF) is driven by __________.
Translocation of three to four protons drives the F0 component of ATPase which in turn phosphorylates one ADP into ATP.
How does the proton motive force lead to production of ATP?
The terminal electron acceptor in anaerobic respiration is not oxygen.
How is anaerobic respiration different from aerobic respiration?
anabolism.
The sum of all biosynthetic reactions in a cell is known as
