Straighterline Micro 250 Final Exam Prep Latest

pg. 1 Straighterline Micro 250 Final Exam Prep Latest Update - Correct Verified Answers/ Graded A+

The purpose of staining cells on a microscope slide is to ______.

Select one:

• kill them
• secure them to the slide
• enlarge the cells
• add contrast to see them better
• observe motility - Correct Answer - add contrast to see them better

Many chronic infections are caused by microbes that associate in communities termed

______.

Select one:

• biofilms
• virions
• sediments
• microbiota - Correct Answer – biofilms

Microorganisms are best defined as organisms that

Select one:

• cause human disease.
• lack a cell nucleus.
• are infectious particles.
• are too small to be seen with the unaided eye. 1 / 4

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• can only be found growing in laboratories. - Correct Answer - are too small to be

seen with the unaided eye.

Studies of the immune response to an infection caused by microorganisms would be performed by a(n) ______.

Select one:

• hypersensitivity specialist
• epidemiologist
• immunologist
• geomicrobiologist - Correct Answer - immunologist

Robert Koch and his colleagues first used agar in bacteriological media. Why was this ingredient an improvement on previous materials used to culture bacteria?

Select one:

• Bacteria growing on the solidified medium did not degrade or break down the agar.
• Agar can convert from liquid to solid form, and back again, very easily.
• Agar was less expensive than the nutrients that Koch was previously using in the lab.
• Agar is a complete source of nutrients for most bacteria. - Correct Answer - Bacteria

growing on the solidified medium did not degrade or break down the agar.

An example of an amphipathic molecule found in living cells is ______.

Select one:

• glucose
• phospholipid
• protein
• nucleic acid
• ATP - Correct Answer - phospholipid

A diagram of the three domains (Bacteria, Archaea, Eukarya) proceeding from the Last Universal Common Ancestor would show Archaea 2 / 4

pg. 3

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

An atom has gained an electron; it has been ______.

Select one:

• oxidized
• reduced
• ionized
• deionized
• neutralized - Correct Answer - reduced

Analysis of the small subunit rRNAs from all organisms in the three current domains suggests that

Select one:

• the eukaryotes arose from prokaryotes.
• the Archaea are more closely related to bacteria than eukaryotes.
• all modern and extinct organisms on earth arose from a common ancestor.
• the prokarytoes, archaea, and eukaryotes are not related. - Correct Answer - c. all

modern and extinct organisms on earth arose from a common ancestor.

Most biochemical macromolecules are polymers, which are chains of ______.

Select one:

• hydrophobic molecules
• electrolytic molecules
• repeating monomers
• repeating carbohydrates 3 / 4

pg. 4

• hydrogen bonds - Correct Answer - repeating monomers

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

Select one:

• complex
• reducing
• enriched
• synthetic - Correct Answer - complex

One nucleotide contains one

Select one:

• phosphate.
• pentose sugar.
• nitrogen base.
• All of the choices are correct. - Correct Answer - All of the choices are correct.

Characteristics shared by all cells include

Select one:

• a membrane serving as a cell boundary.
• the possession of genetic information.
• the presence of cellular fluid.
• All of the choices are correct. - Correct Answer - All of the choices are correct.

The important solvent associated with living things is ______.

Select one:

• carbon dioxide
• sodium chloride
• ethyl alcohol
• / 4