Question 1

A procedure that divides organisms into two or more groups depending on their individual reactions to the same staining procedure is referred to as __________ staining.

Accepted Answer

The answer of A procedure that divides organisms into two...

Question 2

The Gram-staining procedure is an example of:

Accepted Answer

The Gram-staining procedure is a differential staining technique that separates bacteria into two groups based on differences in their cell walls. This staining procedure is used in microbiology to identify different types of bacteria and is a commonly used laboratory technique.

Question 3

Small internal cell structures are best visualized with a

Accepted Answer

Small internal cell structures such as organelles and subcellular components are best visualized with a transmission electron microscope (TEM) as it has high magnification and resolution allowing for detailed visualization of internal cellular structures. Light microscopes have limited resolution and are best for observing larger structures, whereas dark-field and flagellar microscopes are specialized microscopes for specific types of observations.

Question 4

The designer of the first transmission electron microscope,_________________,was awarded the 1986 Nobel Prize in physics.

Accepted Answer

The answer of The designer of the first transmission electron...

Question 5

It was possible to view viruses only after the invention of the electron microscope because they are too small to be seen with a light microscope.

Accepted Answer

Viruses are extremely small, typically between 20-300 nanometers in size. They are too small to be seen with a traditional light microscope, which has a limited magnification capacity of about 1000x. The invention of the electron microscope in the 1930s allowed for much higher magnification, making it possible to observe and study viruses in detail.

Question 6

Negative staining with India ink can be used to reveal the presence of capsules that surround bacterial cells.

Accepted Answer

India ink is a useful negative stain that can be used to reveal the presence of capsules around bacterial cells. The ink does not penetrate the capsule, so the capsule retains its color while the background is stained dark. This creates a clear contrast between the capsule and the surrounding medium, allowing for visualization of the capsule's presence.

Question 7

The _________________ microscope is capable of atomic resolution of specimens,even when they are immersed in water.

Accepted Answer

The answer of The _________________ microscope is capable of atomic...

Question 8

Mordants increase the binding between a stain and specimen.

Accepted Answer

Mordants are used to increase the binding affinity between a stain and the specimen, making it more visible and durable for observation under a microscope.

Question 9

The Gram-staining procedure is widely used because it allows rapid identification of a microorganism with little additional testing.

Accepted Answer

The answer of The Gram-staining procedure is widely used because...

Question 10

In transmission electron microscopy,spreading a specimen out in a thin film with uranyl acetate,which does not penetrate the specimen,is called

Accepted Answer

The spreading out of a specimen in a thin film with uranyl acetate that does not penetrate the specimen is known as negative staining, and option D correctly describes it. This technique makes the specimen appear dark against a lighter background, providing contrast and allowing for the visualization of fine details without the need for electron-absorbing dyes or heavy metal stains. Option A, freeze-etching is a technique that involves freezing a specimen and then fracturing it to reveal internal structures, while options B and C, simple staining and shadow staining, require the use of specific dyes or stains to visualize the specimen.

Question 11

Because transmission electron microscopy uses electrons rather than light,it is not necessary to stain biological specimens before observing them.

Accepted Answer

Although transmission electron microscopy uses electrons instead of light, it is still necessary to stain biological specimens with heavy metals such as osmium or lead, in order to increase contrast and improve visibility of structural details under the microscope.

Question 12

__________ breaks frozen specimens along lines of greatest weakness,often down the middle of lipid bilayer membranes so that they may be observed by transmission electron microscopy.

Accepted Answer

The answer of __________ breaks frozen specimens along lines of...

Question 13

Scanning electron microscopy is most often used to reveal

Accepted Answer

Scanning electron microscopy is primarily used to reveal surface structures, as it uses a focused beam of electrons to create a detailed image of the sample's surface. While it can provide some information about internal structures through the use of cross-sectional imaging techniques, this is not its primary function.

Question 14

Thin films of bacteria that have been air-dried onto a glass microscope slide are called __________.

Accepted Answer

The answer of Thin films of bacteria that have been...

Question 15

An electron microscope uses __________ lenses to focus beams of electrons onto a specimen.

Accepted Answer

The answer of An electron microscope uses __________ lenses to...

Question 16

Scanning electron microscopes bombard specimens with a stream of electrons; however,the specimen image is produce by electrons that are derived from atoms of the specimen itself rather than by the electrons used to bombard the specimen.

Accepted Answer

This is correct. The scanning electron microscope works by using a beam of electrons to "scan" a specimen, and the image produced is created by detecting the secondary electrons and backscattered electrons that are emitted from the specimen in response to the incoming electron beam. These electrons come from the atoms of the specimen itself, not from the electrons used to bombard it.

Question 17

The procedure in which a single stain is used to visualize microorganisms is called __________ staining.

Accepted Answer

The answer of The procedure in which a single stain...

Question 18

In order to stain flagella so that they may be readily observed by light microscopy,it is usually necessary to increase their thickness.

Accepted Answer

Flagella are too thin to be observed directly under a light microscope, so staining techniques that increase their apparent thickness are used to make them visible.

Question 19

__________ is the process by which internal and external structures of cells and organisms are preserved and maintained in position.

Accepted Answer

The answer of __________ is the process by which internal...

Question 20

Regions of a specimen with higher electron density scatter ___________ electrons and,therefore,appear __________ in the image projected onto the screen of a transmission electron microscope.

Accepted Answer

Regions of a specimen with higher electron density scatter more electrons, which results in more electrons reaching the projector lens and creates a darker image on the screen of a transmission electron microscope.

Quiz 2: Microscopy