The resolving power of a microscope is described as the ability of the microscope to
view as separate two objects that are very close together
In viewing a microscopic specimen, emersion oil is used to
Improve the resolution and increase the refractive index
Which of the following microscope types would be the most useful in view unstained living cells?
The acid-fast stain
uses both carbolfusion and methylene blue; stains a small group of organisms with a waxy cell envelope such as Mycobacterium
Which is true concerning the cell wall of prokaryotes?
it helps cell maintain shape, prevents cell from bursting in high salt conditions, is composed of peptidoglycan, it is the target of some antimicrobials
A physician sends a stool sample to your lab, and wants to know if there are lactose fermenting Gram-negative microbes in the sample. How might you determine if these microbes are present or not from this mixed-microbe specimen?
Plate the specimen on MacConkey agar
A bacterial culture medium that inhibits the growth of organisms other than the one being sought is termed a
All the bacterial cells that result from the replication of a single original bacterial organism are said to be
A urine sample with more than 100,000 organisms is considered indicative of infection. A urine sample containing 5,000 bacteria, with a generation time of 30 minutes, sits for 3 hours before finally being assayed. How many bacteria will then be present within the sample after 3 hours?
5,000 x 2^6 = 320,000
One would expect most strict (obligate) anaerobic organisms to have enzymes that detoxify reactive oxygen molecules.
All of the following are part of the cell envelope (inner and outer membrane) of Gram-Negative cells:
Phospholipids, peptidoglycan, lipid A
NOT techoic acid
You are working in a clinical laboratory in a hospital setting. You're handed a throat swab from a patient. You are told specifically that the physician is only interested in what kind Gram-positive cells present. What might you do first to go about working towards this goal?
You culture the bacteria on the swab on medium that is selective from Gram-positive cells, while suppressing the growth of Gram-negative cells.
In doing the gram stain, you accidently forgot to stain with safranin. What would be the color of gram-negative organisms?
Transport across the cytoplasmic membrane of prokaryotes that requires the expenditure of energy is called
Which of the following would improve the resolution of a microscope
Increasing the refractive index (D=0.61x/rsin@)
The scientist usually considered the first to see live microorganisms, which he called "animalcules", was
are normal residents on or in our body / may occupy spaces that otherwise would be occupied by pathogens
Which is usually true of bacteria
They are rods, spheres, or spirals in shape/they are usually single celled/they reproduce by binary fission/they contain a rigid cell wall of peptidoglycan
Amino acids in proteins are linked to one another by peptide bonds between the
terminal carboxyl group of one amino acid and the terminal amino group of another amino acid