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MCB 2610 Exam 2 Questions with complete solution 2024/2025 R251,14   Add to cart

Exam (elaborations)

MCB 2610 Exam 2 Questions with complete solution 2024/2025

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  • MCB 2610

MCB 2610 Exam 2 Questions with complete solution 2024/2025 MCB 2610 Exam 2 (Dr. Ortenberg) Morphology: Form - correct answer Punctiform, Circular, Filamentous, Irregular, Rhizoid, Spindle Morphology: Elevation - correct answer Flat, Raised, Convex, Pulvinate, Umbonate Morphology: Ma...

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  • October 17, 2024
  • 39
  • 2024/2025
  • Exam (elaborations)
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  • MCB 2610
  • MCB 2610
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MCB 2610 Exam 2 (Dr. Ortenberg)
Morphology: Form - correct answer ✔Punctiform, Circular, Filamentous,
Irregular, Rhizoid, Spindle


Morphology: Elevation - correct answer ✔Flat, Raised, Convex, Pulvinate,
Umbonate


Morphology: Margin - correct answer ✔Entire, Undulate, Lobate, Erose,
Filamemtous, Curled


Types of microbial associations? - correct answer ✔Symbiotic vs.
Nonsymbiotic


Symbiotic Microbial Association - correct answer ✔Organisms live in close
nutritional relationships; required by one or both members


Non-Symbiotic Microbial Association - correct answer ✔Organisms are free-
living; relationships with other microbes not required for survival


Types of symbiotic relationships - correct answer ✔mutualism,
commensalism, parasitism


Mutualism - correct answer ✔An obligatory relationship between two species
in which both species benefit from / are dependent on the other


Commensalism - correct answer ✔A relationship between two organisms in
which one organism benefits and the other is unaffected

,Parasitism - correct answer ✔A relationship between two organisms in which
the parasite is dependent on and benefits from the host, while the host is
harmed.


Types of non-symbiotic relationships - correct answer ✔Synergism and
Antagonism


Synergism - correct answer ✔Free-living organisms; members cooperate
and share nutrients/resources with one another


Antagonism - correct answer ✔Free-living organisms; some members living
in antagonistic non symbiotic relationships are inhibited / out-competed /
restricted by other organisms


Human-Microbial Associations - correct answer ✔can be commensal
(microbe benefits and dependent on human, human not harmed), parasitic
(parasite dependent on / benefits while harming human), or synergistic
(human and free-living microbe not dependent on human for survival share
nutritional resources with one another)


What makes up humans normal microbial flora? - correct answer ✔symbiotic
bacteria, fungi, some/few protozoa


During the microbial growth phase, how much does each fission cycle
increase the population by? - correct answer ✔Each binary fission cycle
increased the population by a factor of two


Generation Time - correct answer ✔also called doubling time- is the time
required for a cell to undergo a complete fission cycle. Species and
environment variable, so time can range from minutes to days

,Quorum Sensing - correct answer ✔The ability of bacteria to sense the
presence of, communicate, and cooperate with other bacteria via secreted
chemical signals along a biofilm


Steps of binary fission - correct answer ✔In bacteria-
1. parent cell enlarges
2. duplicates its chromosome
3. forms a central transverse septum that divides the cell equally in half
4. cell membrane patches itself so that there are two separate cell chambers
5. split into 2 daughter cells which are now independent units (some bacterial
species will remain attached / form pairs or chains)


Biofilm - correct answer ✔The extra-cellular matrix formed when a colony of
one or more microbial species attach and bind to a substrate that allows them
to engage in metabolic cooperation


Transverse Binary Fission - correct answer ✔Primary mechanism for
bacterial cell division- bacterial cells mode of asexual reproduction


Levels of microbial growth - correct answer ✔cellular level growth increases
size
population growth increases population size


During the growth / log phase of microbial growth, what sort of trend is seen? -
correct answer ✔cell population is doubled during the microbial growth
phase which can be indicated by an exponential period of growth during their
life cycles.


What methods can be used to measure and quantify microbial population
growth? - correct answer ✔1. direct counts

, 2. viable (living) cell counts
3. turbidity measurements
4. flowcytometry


What is the "direct count" method? - correct answer ✔1. Add known volume
of bacterial suspension onto a gridded slide in the center of the Petroff-
Hausser counting chamber
2. Lower coverslip over the grid and ensure the suspension distributes evenly
with excess in the side channels
3. Use a light microscope to count the individual cells present in the grid- can
be automated or manual


Petroff-Hausser - correct answer ✔the counting chamber is a gridded slide
tool used to directly count the number of microbial cells present in a
designated volume of bacterial suspension.


How can the number of viable / live cells present in an original sample be
measured? - correct answer ✔Using the spread plate or pour plate
technique- Following incubation, colonies are counted, measurement used to
determine number of viable microorganisms in an original sample in units of
CFU


Ways to facilitate microbial growth using solid media? - correct answer
✔Pour plate and spread plate
(pour plate often more accurate but yields lower CFU values)


Pour Plate- Results and Process? When is it used? - correct answer
✔Inoculated colonies grow in and on top of a solidified medium.
Empty plate is inoculated with specific volume of sample and melted nutrient
agar is poured on top and swirled together.

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