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50 terms

Test 1

STUDY
PLAY
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?
Phase contrast
Basic dyes
are positively charged and bind well to DNA
Which of the following stains is considered differential
Gram stain and acid fast stain
The order of reagents in the Gram stain reaction are
crystal violet, iodine, alcohol, safranin
The acid-fast stain
uses both carbolfusion and methylene blue; stains a small group of organisms with a waxy cell envelope such as Mycobacterium
India ink is an example of
a negative stain and a capsule stain
Which term refers to bacterial morphology
Coccus, Spirilium, and Bacillus
Most hydrophilic solutes pass through the cytoplasmic membrane of bacteria via
transport proteins
LPS is found in the outer membrane of Gram-positive bacteria.
False
Which of the following bacteria lack a cell wall?
Mycoplasma pneumonia
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
selective
All the bacterial cells that result from the replication of a single original bacterial organism are said to be
pure culture
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
A hot tub (approx. 104 F or 40 C) would most likely contain
Mesophiles
Organisms that require molecular oxygen (O2) for metabolism are referred to as
Obligate aerobes
Enzymes that destroy toxic oxygen intermediate molecules include
superoxide dismutase and catalase
Organisms that use CO2 as their source of carbon are called
Autotrophs
One would expect most strict (obligate) anaerobic organisms to have enzymes that detoxify reactive oxygen molecules.
False
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.
Which of the following distinguish nucleotides of RNA from DNA?
Uracil and ribose
Bacterial flagella move in a counter-clockwise rotation during a tumbling event.
False
In doing the gram stain, you accidently forgot to stain with safranin. What would be the color of gram-negative organisms?
colorless
The 70S prokaryotic ribosome is composed of a 30S subunit and a ___ subunit
50S
Transport across the cytoplasmic membrane of prokaryotes that requires the expenditure of energy is called
active transport
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
van Leeuwenhoek
The idea of Spontaneous Generation postulated that
Organisms could arise from non-living material
Bioremediation refers to
using bacteria to clean up pollutants
Bacteria
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
Both Eubacteria and Eukarya contain membrane bound intracellular organelles.
False
The parts of the atom that are most involved in chemical reactivity (bonding) are
Electrons
The sharing of electrons between two atoms constitutes a
covalent bond
The bonds between hydrogen and oxygen atoms within a molecule of water are
polar covalent
What type of bonding holds one strand of DNA to the complementary strand of DNA?
hydrogen
The sugars found in nucleic acids consists of
5 carbons
The components of fats are long chain acids and
Glycerol
Water soluble (hydrophilic) compounds freely pass through the membranes of bacteria.
False
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
The primary structure in a protein refers to the
sequence of amino acids in the polypeptide
Weak bonds are important in the _____ structure of a protein.
secondary, tertiary, and quaternary
Dehydration reactions are involved in the formation of
polypeptides and polysaccharides
Phospholipids are amphipathic molecules.
True
Helices and B sheets of amino acids form a protein's
secondary structure
The magnifying lenses found in a compound light microscope are the
objective lens and ocular lens