BIO 438 Exam 1 Practice Questions and 100% Correct Answers
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Module
BIO 438
Institution
BIO 438
Bright field The most commonly used type of microscopy is called _____, because the specimens produce dark images against brighter backgrounds.
Dark field In ______ microscopy, however, bright images on a darker background are produced because only light that is refracted by the specimen is captur...
BIO 438 Exam 1 Practice Questions and
100% Correct Answers
Bright field ✅The most commonly used type of microscopy is called _____, because
the specimens produce dark images against brighter backgrounds.
Dark field ✅In ______ microscopy, however, bright images on a darker background
are produced because only light that is refracted by the specimen is captured.
Phase contrast ✅The _____ microscope uses slight differences in refractive indices
and an annular condenser to produce sharper images than simple bright-field
microscopy.
Differential interference contrast ✅When polarized light is needed for imaging a
______ microscope is used.
Epifluorescence ✅Light at specific wavelengths is used to excite dyes in specimens
that then emit light at specific wavelengths in _______ microscopy.
Confocal ✅Laser light is used in _______ microscopy, generating three-dimensional
images.
Bacteria and archaea are genetically distinct from each other
Both bacteria and archaea have cytoskeletal components
It is preferable to define an organism by what is contains rather than what it lacks
✅Select the true statements with respect to the use of the term "prokaryote"
Flagella ✅Which of the following bacterial structures are most directly linked to
swimming motility in chemotaxis?
Proton motive force ✅The bacterial flagellum is driven to rotate by protons moving
down a charge and ph gradient and the energy provided is called the _________
___________ ____________.
Boiling to 100°C will kill vegetative C. Botulinum cells, but any spores will survive to
temperatures of 120°C ✅Why is boiling at standard temperature and pressure an
inadequate method of processing for canned foods?
Core has low water content
Core has high amounts of dipicolinic acid complex with calcium ions
, Core has slightly acidic ph ✅Review the properties of endospores that allow them to
survive adverse environmental conditions by selecting protective properties of the
endospore core below.
Sex pilus ✅Responsible for transferring DNA from one bacterial cell to another
Fimbriae ✅Responsible for bacterial attachment to surfaces
Flagella ✅Responsible for locomotion
False ✅Germination is one process by which bacterial cells can reproduce.
It still tumbles to change direction but it occurs less often than in the absence of a
chemical, and runs more creating an overall net motion in one direction ✅Bacterial
movement toward or away from a chemical is often described as a "random biased
walk" due to the fact that __________.
Endospore ✅Clostridium botulinum, which produces a toxin that causes botulism, is a
major concern of the food industry due to its production of an extremely heat-resistant
________.
At a temperature of 90oc ✅Archaea with a plasma membrane composed of a
tetraether monolayer would most likely be found __________.
Cell membranes require a hydrophobic interior and two hydrophilic surfaces to be an
effective barrier between the cell cytoplasm and its external environment.
Membrane lipids are covalently bonded to glycerol.
Membrane thickness is equivalent to a 40-carbon hydrocarbon chain either in the form
of two C20 bilayers, or a single C40 monolayer. ✅Considering the diversity of
membranes and their components in bacterial and archaeal cells, which of the following
statements are correct about membranes in BOTH domains?
Polypeptides are enriched in amino acids like proline that limit their flexibility.
The enzyme reverse DNA gyrase alters the supercoiling in the chromosome.
Membrane lipids are higher molecular weight, more branched, and more saturated.
✅Which of the following are adaptations used by thermophiles to survive in high
temperature environments?
Ftsz localization determines the site of cell wall growth by recruiting pbps for
peptidoglycan synthesis.
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