Straighterline Micro 250 final prep Latest

Straighterline Micro 250 final prep Latest Update 230 Questions and 100% Verified Correct Answers Guaranteed A+ At First Attempt _____ solution was introduced in the late 19th century for preventing gonococcal infections in a newborn's eyes after exposure to the mother's infected birth canal.

Select one:

• Merthiolate
• Triclosan
• Betadine
• Silver nitrate

e. Zinc oxide - Correct Answer :Silver nitrate

A bacterium that you isolated from pond water appears to use light for energy. Based upon this information, you inoculate the organism into fresh media, infused with lots of carbon dioxide. Even after incubation at the correct temperature (of pond water), the organism is not growing. Your best explanation of what might have happened is

Select one:

• there was no sulfur compound added to the medium, that could be used as an

electron donor.

• no oxygen was added to the medium so the organism died.
• there is some inhibitory chemical that is preventing the growth of the bacterium.
• you were using the wrong type of sunlight as the energy source for the bacterium. -

Correct Answer :there was no sulfur compound added to the medium, that could be

used as an electron donor.

A diagram of the three domains (Bacteria, Archaea, Eukarya) proceeding from the Last Universal Common Ancestor would show Archaea

Select one:

• as the original cells from which the others derived.
• branching off the Domain Eukarya.
• branching off the Domain Bacteria. - Correct Answer :branching off the Domain

Eukarya

A fat is called _____ if all carbons of the fatty acid chain are single-bonded to 2 other

carbons and 2 hydrogens. - Correct Answer :saturated

A group of protozoa that are not motile are the ______.

Select one:

• amoebas
• ciliates
• trophozoites 1 / 4

• Plasmodium sp.

e. dimorphics - Correct Answer :Plasmodium sp.

A microaerophile

Select one:

• grows best in an anaerobic jar.
• grows with or without oxygen.
• needs normal atmospheric levels of oxygen.
• requires a small amount of oxygen but won't grow at normal atmospheric levels of

oxygen. - Correct Answer :requires a small amount of oxygen but won't grow at normal atmospheric levels of oxygen.

A microbiologist inoculates Staphylococcus epidermidis and Escherichia coli into a culture medium. Following incubation, only the E. coli grows in the culture. What is the most likely explanation?

Select one:

• The microbiologist used too much inoculum.
• The culture was contaminated.
• The incubation temperature was incorrect.
• The culture medium was selective.
• The culture medium was differential. - Correct Answer :The culture medium was

selective.

A microbiologist must culture a patient's feces for intestinal pathogens. Which of the following components would likely be present in a selective medium for this purpose?

Select one:

• NaCl
• Sheep red blood cells
• Bile salts
• Thioglycolic acid

e. Peptone - Correct Answer :Bile salts

A microorganism that does not have catalase or superoxide dismutase would find it difficult to live in an environment with ______.

Select one:

• carbon dioxide
• oxygen
• high salt
• temperatures above 37° C

e. high acidity - Correct Answer :oxygen

A mutation that changes a normal codon to a stop codon is called a ______ mutation.

Select one:

• point
• silent
• back 2 / 4

• missense

e. nonsense - Correct Answer :nonsense

A nutrient medium that contains at least one ingredient that is not chemically defined is termed ______.

Select one:

• complex
• reducing
• enriched

d. synthetic - Correct Answer :complex

A nutrient medium that contains at least one ingredient that is not chemically defined is termed ______.

Select one:

• complex
• reducing
• enriched

d. synthetic - Correct Answer :complex

A pure culture contains

Select one:

• only one identified species of microorganism.
• only bacteria.
• microbes from a single source.
• a variety of species from the same genus. - Correct Answer :only one identified

species of microorganism.

A pure or mixed sample of known microbes added to food is a(n) ______.

Select one:

• leavening
• fermenter
• starter culture
• flavor inducer

e. aerator - Correct Answer :starter culture

A reducing medium contains

Select one:

• sugars that can be fermented.
• extra oxygen.
• hemoglobin, vitamins, or other growth factors.
• substances that remove oxygen.

e. inhibiting agents. - Correct Answer :substances that remove oxygen.

A reducing medium is used to culture ______ organisms.

Select one:

• fastidious 3 / 4

• aerobic
• anaerobic

d. pathogenic - Correct Answer :anaerobic

A scientist studying the sequence of nucleotides in the rRNA of a bacterial species is working on

Select one:

• determining evolutionary relatedness.
• bioremediation.
• recombinant DNA.
• nomenclature.
• determining if that species is the cause of a new disease - Correct Answer

:determining evolutionary relatedness.

A screening system called the _______ test is used for detecting chemicals with carcinogenic potential.

Select one:

• Koch
• Ames
• mutation
• cancer

e. Iowa - Correct Answer :Ames

a spongiform encephalopathy of humCorrect Answer :- Correct Answer :Creutzfeldt- Jacob disease

All cells contain

Select one:

• ribosomes for protein synthesis.
• cell walls made of cellulose.
• uracil in their DNA.
• organelles for compartmentalization.
• mitochondria to generate ATP. - Correct Answer :ribosomes for protein synthesis.

All of the following are associated with IgE and mast-cell-mediated allergy except

______.

Select one:

• drug allergies
• eczema
• anaphylaxis
• allergic asthma

e. systemic lupus erythematosus - Correct Answer :systemic lupus erythematosus

All of the following are lipids except ______.

Select one:

• cholesterol
• / 4