BIOL 438 Midterm 1 Exam Questions and Correct Answers
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Course
BIO 438
Institution
BIO 438
Some molecules needed for survival cannot be synthesized by the cell but instead must be obtained from the environment. These types of molecules include vitamins and amino acids and are collectively called ______ ______. growth factors
The movement of dissolved solutes from a region of higher conc...
BIOL 438 Midterm 1 Exam Questions and
Correct Answers
Some molecules needed for survival cannot be synthesized by the cell but instead must
be obtained from the environment. These types of molecules include vitamins and
amino acids and are collectively called ______ ______. ✅growth factors
The movement of dissolved solutes from a region of higher concentration to a region of
lower concentration is called _______. ✅diffusion
Nutrient uptake and diffusion of molecules into the bacterial cell become more efficient
as the surface area-to-volume ratio _________. ✅increases
Many bacteria have overcome the difficulty of iron uptake by secreting low-molecular,
weight iron-binding proteins called _________. ✅siderophores
A fellow student carries out the Gram stain on a mixed culture containing Gram-
negative rods and Gram-positive cocci and finds purple colored cocci and clear (no
color) rods when viewing the prepared slide with a microscope. From the following,
choose the best reason for these results. ✅the student forgot to add counterstain
After conducting the Gram stain on a mixed culture containing Gram-positive rods and
Gram-negative cocci, all the cells were purple in color. This was most likely because
________. ✅the cells were not decolorized enough with alcohol or acetone
The capsule is ✅well organized, not easily removed, and helps resist phagocytosis
The slime layer is ✅disorganized, easily removed, and facilitates motility
Capsules and slime layers are networks of polysaccharides that can extend from the
bacterial surface. Both capsules and slime layers can be encompassed by the general
term _________________. ✅glycocalyx
Gram positive bacteria ✅stain purple, have thick peptidoglycan, teichoic acids present,
outer membrane absent, LPS absent, more sensitive to penicillin, sensitive to lysozyme
Gram negative bacteria ✅stain pink, thin peptidoglycan, teichoic acids absent, outer
membrane present, LPS present, less sensitive to penicillin, not sensitive to lysozyme
When analyzing the outer membrane of Gram-negative bacteria, which part of
lipopolysaccharide induces an antibody response? ✅O antigen
, In the Gram-positive bacterial cell wall, the tetrapeptides that extend from the
peptidoglycan layers are linked by ______. ✅peptide interbridges
Which of the following is a component of the outer membrane in Gram-negative bacteria
that results in septic shock upon entering the bloodstream? ✅lipopolysaccharide (LPS)
Sex pilus ✅responsible for transferring DNA from one bacterial cell to another
Fimbriae ✅responsible for bacterial attachment to surfaces
Flagellum ✅responsible for locomotion
T/F: germination is one process by which bacterial cells can reproduce ✅False;
Germination refers to an endospore taking on water and returning to a vegetative state
and becoming an active bacterium. It is a form of bacterial survival not reproduction
The bacteria flagellum is driven to rotate by protons moving down a charge and ph
gradient and the energy provided is called the _________ ___________
____________. ✅proton motive force
Which bacterial structure is most directly linked to swimming motility in chemotaxis?
✅flagella
Endospore properties that allow them to survive adverse environmental conditions
(properties of endospore core) ✅high amounts of dipicolinic acid complexed with
calcium ions, slightly acidic ph, low water content
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 ________.
✅endospore
Archaeal characteristics ✅membranes can be monolayers or bilayers, cell envelope
often contains an S layer, chromosomes associated with histones, membrane lipids
contain isoprenic hydrocarbons, produce hammi and cannulae
Bacteria characteristics ✅lipids with fatty acids attached to glycerol by ester bonds, cell
envelopes with peptidoglycan, hollow flagella, flagellar rotation powered by proton
motive force
Archaea with a plasma membrane composed of a tetraether monolayer would most
likely be found ______. ✅at a temperature of 90 C
Pelagibacter ubique is a prominent species of bacteria that are free floating in the
oceans of the world; as free-floaters they are ✅planktonic
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