Exam (elaborations)
ANSC 326 Questions with complete solutions.
- Course
- ANSC 4100
- Institution
- University Of Guelph (U Of G )
ANSC 326 Questions with complete solutions.
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ANSC 326 Questions with complete solutionsWhich of the four phases of a microbial population's growth and
development would be the best for optimally preserving food quality,
shelf life, and protecting food safety? Correct Answer-exponential?
In the image below depicting the onset of sublethal injury in a
population of a microorganism, which line (solid or dotted) correctly
depicts the actual population of living/viable microorganisms during
processing exposure and thereafter? Each line depicts the changes in
counts of a microorganism in the food by use of a microbiological
medium: the solid line on a non-selective medium and the dashed line on
a selective medium. Correct Answer-solid line
The image below demonstrates that with respect to a bacterium's
response to an acidic environment, one mechanism of responding to
excess acidity outside the cell is to activate an ATP-using pump to eject
any protons that may enter the cell cytoplasm, though this consumes
energy and may inactivate the cell through energy reserves depletion.
Correct Answer-true
As it regards acid tolerance responses, a chaperone protein may be
produced in highly acidic conditions in order to assist survival by
protecting native DNA supercoiling or protein folding structure. Correct
Answer-true
In a mixed microbial ecology, poor ________________ are organisms
that tend to be ineffective at efficiently obtaining and using various
,sources of nutrition and water when compared to other microbial
ecology participants. Correct Answer-competitors
Which letter correctly identifies the logarithmic/exponential growth
phase in the image below? Correct Answer-b
Which grouping of microorganisms is described as growing optimally at
temperatures above 40 Celsius, and in some instances may exhibit
growth at temperatures exceeding 70 Celsius? Correct Answer-
thermophiles
_________________________ anaerobic bacteria are those that can
exhibit metabolism and growth in both oxygenated and anaerobic
environments; Salmonella is an example of such an organism. Correct
Answer-facultative
___________________________ relies upon the interpretation of
external chemical stimuli by the binding of the chemical compound to a
membrane-associated histidine kinase, followed by a conformational
change in the enzyme and a consequent change in cell activity. Correct
Answer-signal transduction
As it relates to thermal processing, in the U.S. there is a mandated 12-D,
or 12 log-cycle inactivation requirement for Clostridium botulinum
spores in a low acid canned food. Correct Answer-true
,Of a yeast, mold, virus, or bacterium, which was described as a
eukaryotic/higher order multicellular microorganism that can replicate in
various ways, but typically grows aerobically, producing a mycelium. Its
presence in a food may indicate a concern not only for food safety but
also frequently for potential food spoilage, and when looking across the
various species that may contaminate foods, these microbes tend to
exhibit the greatest survival across very acidic to very alkaline foods?
Correct Answer-mold
A __________________ is an agent or something with the potential to
cause harm or injury. Correct Answer-hazard
The figure given below reproduces the basic design of the bacterial
spore. Which letter correctly identifies the cortex that mechanically
dehydrates the spore core and contributes to its processing resistance?
Correct Answer-b
While bacteria may use differing carbohydrate catabolic (consuming)
metabolic pathways, the three primary pathways all possess the ability to
consume glucose, a simple sugar, in order to yield energy in the form of
ATP. Correct Answer-true
The Q10 principle relates that the rate of microbial enzymatic activity
increases 10-fold every time the environmental temperature is increased
by 10 Celsius. Correct Answer-true
, A microorganism that is described as being nutritionally fastidious is
one that can consume both simple and complex nutrient sources with
equal efficiency. Correct Answer-false
In a food that has undergone some process of dehydration/drying, some
microorganisms may utilize chemical compounds that they accumulate
in the cytoplasm to prevent the excess loss of water from the cell's
cytoplasm. These compounds may include sugars, alcohols, and even
some amino acids, but one key attribute of all of them are that they are
not metabolized by the bacterium. What term identifies these
compounds in this application? Correct Answer-compatible solutes
Organisms that respire optimally on low amounts of oxygen, 3-6% O2,
are identified as microaerophiles (also called microaerobes). Correct
Answer-true
From the recorded presentation on bacterial sporeformers, a food that is
processed to be free of microbial pathogens as well as other organisms
that would otherwise replicate/grow during conditions of shelf storage
post-processing is said to be commercially pasteurized. Correct Answer-
false
A bacterium that cannot be cultured on any microbiological medium,
including non-selective media, but can be identified to be living through
cell staining and metabolic analyses can be said to be _________ but
non-culturable. Correct Answer-viable
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