Lab Quiz 2

After you position the specimen over the opening in the stage and rotate one of the low-power lenses into position, what step should be completed next?

While looking at the microscope from the side, lower the body tube with the coarse-adjustment knob.

Which of the motility groups is represented in this micrograph?

ciliates

When you look through the ocular lenses, you see this image of the endospore-forming bacteria Bacillus anthracis under oil. Which of the following qualities is most lacking in this image?

contrast

Which of the following is the most appropriate way to carry a microscope?

hand on arm and hand on the base

Immersion oil should be cleaned off an objective with which product?

lens paper

The use of clean lenses increases the efficiency of the microscope. While dry lenses should be cleaned with _____, the oil-immersion lens can be cleaned with _____, followed by 95% ethanol.

lens paper; xylol

With respect to the image of a microscope specimen, refraction of light by the objective lens enhances __________.

magnification

The total magnification achieved by the microscope is calculated by _____ the magnification of the objective and the ocular lens.

multiplying

A compound microscope uses two lenses at once to magnify the image of a specimen. The _____ lens is found in the eyepiece and the _____ lens is found in the revolving nosepiece.

ocular; objective

Which structure is indicated by the arrow in this micrograph of Euglena?

Eyespot

To which motility-based group does this protozoan belong?

Flagellates

What structure is used for motility in Euglena?

Flagellum

Which of the following objective lenses is the ONLY lens that should be used with oil immersion?

High-power lens (100X)

Which of the following statements is TRUE regarding the relative sizes of the different individual cells?

Human blood cells are larger than Bacillus subtilis.

What microscope component should be adjusted to regulate the amount of light entering the condenser in order to ensure the best contrast which changing from one objective lens to another?

Iris diaphragm

Which of the following microscope parts should routinely be adjusted to control the light source and provide optimal illumination of the specimen?

Iris diaphragm

Which of the following is an INCORRECT association?

Iris diaphragm; used to raise and lower the objective lenses to bring the specimen into focus

If you view a specimen at 40X total magnification with a 10X ocular lens, then you are viewing the specimen with what objective?

4X

You should begin viewing a specimen with what objective lens?

4X

Which property of the lens describes its ability to show two adjacent objects as discrete entities?

Resolving power

Which of the following procedures is NOT a recommended practice when returning the microscope to the cabinet?

Rotate the high-power objective lenses into place and raise the body tube.

Which of the following is an INCORRECT association? - Abbe condenser; collects and concentrates light as it passes upward from the light source into the lens system. - Numerical aperture; characteristic of the lens that is a function of the diameter in relation to the focal length. - Objective lens; used to magnify the image of the specimen. - Coarse-adjustment knob; used to regulate the amount of light entering the lens system.

- Coarse-adjustment knob; used to regulate the amount of light entering the lens system.

Based on your observation of the picture fungal spores select ALL appropriate statements.

- The pictured spore could have been made by Rhizopus. - The fungal spores shown are produced asexually. - This is an image of sporangia.

Based on your observation of the picture fungal spores select ALL appropriate statements.

- The pictured spores were most likely made by a Penicillium mold. - This is an image of conidia. - The fungal spores shown are produced asexually.

Based on your observation of this yeast specimen select ALL appropriate statements.

- The yeast shown is in the process of reproducing asexually. - The yeast shown is in a diploid state.

Based on your observation of the picture fungal spores select ALL appropriate statements.

- This is an image of conidia. - The pictured spores were most likely made by an Aspergillus mold. - The fungal spores shown are produced asexually.

Based on your observation of the picture fungal spores select ALL appropriate statements.

- This is an image of zygospores. - A multicellular fungus formed these spores. - The fungal spores shown are produced sexually. - The pictured spores could have been made by Rhizopus.

Which component of the microscope is found directly under the stage, and contains two sets of lenses that collect and concentrate light as it passes upward from the light source into the lens systems?

Abbe condenser

While looking through a microscope at 400X total magnification, you see this image. To improve the quality of this image, what should you do?

Adjust the condenser aperture diaphragm.

You have just rotated the 40X objective into position after viewing the specimen with the 10X objective. What would your next step most likely be?

Adjust the fine focus knob.

Which of the following prepared specimens contained rod-shaped cells?

Bacillus subtilis

You are doing research on wetland water samples and come across this microscopic organism. Assuming this organism is a protozoan, how would you classify it?

Ciliate

When comparing a wet mount preparation to a commercially prepared slide, which of the following characteristics of Protozoa is best observed using a wet mount slide preparation?

Mechanism of motility

What is the purpose of methylcellulose when preparing a wet mount of protozoa?

Methylcellulose increases the viscosity of the mount.

Loss of bent, or refracted, light results in a reduced numerical aperture, which diminishes the resolving power of the objective lens. Adding which of the following substances between the slide and the lens acts to decrease the refraction of light?

Oil

Which structure is used for motility in the organism in the following micrograph?

Pseudopodium

In a compound light microscope, what is the function of the condenser?

To concentrate light on the specimen.

What is the purpose of adding a drop of mineral oil to the slide?

To reduce the amount of light rays that are refracted away from the objective lens