BIOL 265 Quiz Review (CH 1,2,3)

Questions and answers from Canvas quizzes.

Which of the following is an environmental role of microbes?

Break down wastes and convert atmospheric nitrogen into organic compounds

Which factor best explains why a microbe can colonize only certain body sites?

Availability of specific nutrients at the site

Which of the following is a common shape of bacterial cells?

Coccus (spherical)

Which feature best distinguishes algae from fungi and protozoa?

Preform photosynthesis and produce oxygen

Which sequence of steps did Robert Koch use to demonstrate that a bacterium causes a specific disease?

Isolate the bacterium from diseased animals, culture it, inoculate healthy animals, then re-isolate the same bacterium

What key conclusion did Pasteur’s S-shaped (S-flask) experiment demonstrate?

Airborne microorganisms contaminate sterile solutions; air itself does not create life

Which of the following is produced using recombinant DNA techniques?

Vaccines and enzymes

Which group of organisms can naturally convert atmospheric nitrogen into forms usable by plants and animals?

Bacteria

Which best explains why antibiotic-restraint bacteria have become more common?

Overuse and misuse of antibiotics create environments where resistant bacteria thrive

Which of the following provides important resistance against microbes?

The skin, mucous membranes, and immune cells and chemicals

Which particle in an atom is electrically neutral and located in the nucleus?

Neutron

Which atomic property equals the number of protons in an atom’s nucleus?

Atomic Number

Which statement correctly describes how a cations forms?

It loses electrons and becomes positively charged

Atoms that share only one pair of electrons form which type of covalent bond?

Single covalent bond

Which statement best describes catabolic reactions in living organisms?

Decomposition reactions that break large molecules into smaller molecules, ions, or atoms

Which statement best describes a synthesis reaction?

Two or more atoms, ions, or molecules combine to form a larger molecule

Which statement best defines an acid dissolved in water?

Dissociates to produce H+ (protons) and anions

Which expression correctly defines pH?

pH= -log₁₀[H+]

What occurs during dehydration synthesis when two monomers join?

A covalent bond forms between monomers and a water molecule is released

Which description best defines a functional group in organic molecules?

A specific group of atoms commonly involved in chemical reactions that determines many chemical and physical properties of the compound

Which metric symbol and value correctly represent one micrometer?

um= 10^-6 m

Which metric prefix represents one billionth (10^-9) of a meter?

Nano (10^-9)

Why does staining increase the contrast of a specimen in brightfield microscopy?

It changes the specimen’s refractive index relative to its medium, causing light to bend at boundaries and increase contrast

Which calculation gives the total magnification of an image in a compound light microscope?

Objective lens magnification x Ocular lens magnification

Which microscope produces striking three-dimensional surface images by scanning a focused electron beam and detecting secondary electrons?

Scanning Electron Microscope (SEM)

Why do basic dyes stain bacterial cells?

They have colored cations attracted to negatively charged bacterial cells

Which of the following is a function of a mordant in simple staining?

Increase the affinity of the stain for the specimen

Which special staining method produces green endospores within red or pink vegetative cells?

Schaeffer-Fulton endospore stain

Calculate the total magnification of an image in a compound light microscope given that:

Objective lens magnification = 74

Ocular lens magnification = 17

74 × 17 = 1258