Chapter 2 and 3 Connect

A strain of Neisseria gonorrhoeae has undergone a mutation and is no longer able to make pili. Predict the most likely outcome.

The bacteria will become less virulent and will not be able to readily establish infection.

Bacterial and archaeal ribosomes are known as _____ ribosomes, based on their sedimentation coefficient.

70s

Select all that are characteristics of transmission electron microscopes.

Highest practical magnification over 100,000 times. Uses electron beam for radiation source. Adjust current to magnetic lenses to change magnification.

An instrument that magnifies slight differences in the refractive index of cell structures is called a (n) __________ microscope.

Phase contrast

What microscope would be the best to use to view cell surface features of a specimen?

SEM, scanning

What would be the best technique to prepare and view the internal structures of fungal hyphae?

TEM

A fellow student carries out the Gram stain on a mixed culture containing Gram-negative rods and Gram-positive cocci and finds purple colored cocci and clear (no color) rods when viewing the prepared slide with a microscope. From the following, choose the best reason for these results.

The student forgot to add the counterstain.

Which of the following is not true of bacterial plasmids?

They are required for host growth and/or reproduction.

Of the following choices, light passing through ____ would have the lowest refractive index.

air

Lysozyme is an enzyme that lyses

bacteria

A __________ is a polysaccharide layer that lies outside the cell wall and is not easily removed.

capsule

The term used to describe bacteria that are intermediate in shape between spherical and rod-shaped is

coccobacilli

Which bacterial structure may survive if temperatures applied during food preservation processes are too low?

endospores

The lipopolysaccharide (LPS) that is found in the outer membrane of gram-negative bacteria is also known as

endotoxin

A microscope that exposes specimens to ultraviolet, violet, or blue light and forms an image with the light emitted at a different wavelength is called a __________ microscope.

florecence

Bacteria and archaea are typically fixed to slides by ____ while eukaryotes with subcellular structure, such as protists, are typically fixed by ___.

heat,chemicals

Which of the following is a component of the outer membrane in Gram-negative bacteria that results in septic shock upon entering the bloodstream?

lipopolysaccharide

Order the objective lenses listed from the smallest to largest working distance that results when they are used.

oil immmersion; high power; low power

A/an ________ microscope keeps an object in focus when the objective lens is changed.

parfocal

Flexible bacteria with a helical shape are called

spirochetes

After conducting the Gram stain on a mixed culture containing Gram-positive rods and Gram-negative cocci all the cells are purple in color. Most likely

the cells were not decolorized enough with alcohol or acetone.