Chapter 5 Flashcards
The process by which bacteria reproduce is known as
How is asexual reproduction used in prokaryotic cells?
an increase in the population size with each cell being identical to the parent cell
The interval of time between successive binary fissions of a cell or population of cells is known as the
Archaea reproduce by a process known as
How does cytokinesis work in prokaryotes?
an inward pinching of the cell envelope, tubulin homolog is part of the fission ring
Which of the following statements about generation time is correct?
Both A and B, but not C are correct.
Which of the following is not a limiting factor for the growth of microorganisms?
not enough humidity
When relating generation time of microbes to disease, which is a correct general statement that could be made?
The faster the generation time, the shorter the incubation period.
In the log phase of growth
the number of cells in the population increases rapidly.
Which of the following is not one of the four phases of a bacterial growth curve?
At what stage in the bacterial growth curve are there no cell divisions occurring, because the bacteria are adapting to their new environment?
At what stage of a bacterial growth curve are the bacteria growing in size, storing nutrients, and synthesizing enzymes in preparation for binary fission?
At what stage of a bacterial growth curve are the bacteria dividing rapidly and the graph is rising in a straight line?
In humans at what stage of the bacterial growth curve are disease symptoms developing because the bacteria are causing tissue damage?
At what point in the bacterial growth curve are bacteria the most vulnerable to antibiotics?
At what phase does broth become turbid and visible colonies appear on agar in the bacterial growth curve?
At what stage of the bacterial growth curve do the reproductive and death rates equalize?
At what phase in the bacterial growth curve in a patient do antibodies from the immune system and phagocytosis by white blood cells affect the progress of the disease?
In a culture tube at what phase of the bacterial growth curve do available nutrients become scarce and waste products begin to accumulate?
In a bacterial growth curve, when the number of dying cells exceeds the number of new cells formed, what stage are they in?
As a culture of Clostridium enters the decline phase of the growth curve, the vegetative cells will have
Which one of the following diseases does not involve endospores?
Endospores are heat-stable resting forms of all of the bacteria listed below, except
Endospores are very difficult to destroy. Because of this, which of the following techniques will work to get rid of them?
heat them under high pressure for several hours
Under what conditions would you find vegetative growth from Clostridium botulinum endospores?
a vacuumed sealed can of food
Under the conditions of bioterrorism where were endospores from Bacillus anthracis found?
on the surface of the skin
Endospores are found primarily in which kind of organisms?
Gram positive bacillus
Which of the following diseases are all caused by endospore forming Clostridia?
all of the above are correct
Which of the following conditions are most likely to affect the growth of bacteria?
temperature, oxygen and pH
An organism that grows at 5° C is classified as a
Psychrophiles and thermophiles differ with respect to their
best temperature for growth.
A mesophilic bacterium could
All the above are correct.
Most of the human pathogens are
An example of a mesophile that is the most frequently identified cause of infective diarrhea is
Bacteria that can grow only in the absence of oxygen are said to be
Facultative bacteria are those that
grow in the presence or absence of oxygen.
A bacterium that grows only at the bottom of a thioglycollate broth tube should be classified as
A bacterium that grows only at the top of a thioglycollate broth tube should be classified as
A bacterium that grows turbid throughout a thioglycollate broth tube should be classified as
You have isolated an organism from the human intestinal tract. It grows better when you capped the culture tube with a semiporous plug than when you used a plug that is completely permeable to oxygen. This organism should be classified as a(n)
An acidophile would grow best at a pH of
How does the GasPak system work?
The hydrogen in the GasPak reacts with oxygen in the presence of a catalyst to form water, thereby creating an oxygen-free atmosphere.
Most bacteria grow best at
______________ are important food producing bacteria because they can be used to produce dairy products like buttermilk, sour cream and yogurt from milk and cream.
The stomach protects us from a large number of microbes that might be in our food because
of it's high level of acidity
What are organisms called that require high amounts of salt?
There are some mesophilic bacteria that are salt tolerant. An example is
Some organisms like Neisseria grow well in an atmosphere that is low in oxygen and rich in carbon dioxide. This can be created by lighting a candle, putting it in a jar, inserting the culture medium, then closing the lid of the jar. What is the best name for these organisms?
The agar in nutrient agar serves as a`
An important contribution was made to microbiology with the introduction of agar by Robert Koch. Which of the following statements about agar is correct?
All of the above are correct
Which of the following types of media are examples of a chemically undefined medium, or complex medium?
A selective medium is one that
allows one type of bacterium to grow while inhibiting another type.
A soil sample is added to a culture medium that has been designed to promote the growth of the genus Pseudomonas while inhibiting the growth of fungi. This test uses a(n)
How can you take a mixed unknown sample and separate out pure colonies to identify them?
all of the above are possible
Which of the following methods of measuring population growth is a direct count?
standard plate count using a dilution series
they can tolerate acidic pH 2.0 to a pH 9.5
this group has most of the pathogens as they grow at body temperature
these organisms are present in compost piles and hot springs
they require an atmosphere low in oxygen but rich in carbon dioxide
these organisms live at the bottom of the ocean
they survive in environments where the concentration of oxygen is relatively low.
they are insensitive to oxygen and still grow well when oxygen is present.
they grow in either the presence of or a reduced concentration of oxygen
they are able to withstand high pressure
they require relatively high levels of salt