$$\textit{Streptococcus pyogenes}$$

$$2.5 \mu\text{m} = 0.0025 mm$$

Question 1

Which of the following is the correct way to write the scientific name for the bacterium that causes strep throat?

Accepted Answer

$$	extit{Streptococcus pyogenes}$$

Question 2

What is the primary function of the condenser lens in a compound light microscope?

Accepted Answer

To focus light onto the specimen

Question 3

Which of the following best describes the relationship between magnification and field of view in light microscopy?

Accepted Answer

As magnification increases, field of view decreases

Question 4

A student is using a microscope with a 10x ocular lens and a 40x objective lens. What is the total magnification?

Accepted Answer

$$10 	imes 40 = 400$$

Question 5

Why is immersion oil used with the 100x objective lens in light microscopy?

Accepted Answer

To increase the refractive index and improve resolution

Question 6

Which of the following units is the most appropriate for measuring the diameter of a typical coccus-shaped bacterium?

Accepted Answer

Micrometer ($$\mum)$$

Question 7

Which taxonomic rank is more inclusive than family but less inclusive than class?

Accepted Answer

Order

Question 8

A rod-shaped bacterium is measured to be 2.5 $$\mum $$long and 0.8 $$\mum $$wide. Which unit conversion is correct for its length?

Accepted Answer

$$2.5 \mu	ext{m} = 0.0025 mm$$

Question 9

Which of the following best improves contrast when viewing unstained cells under a light microscope?

Accepted Answer

Adjusting the iris diaphragm

Question 10

What is the resolving power of a typical bright-field light microscope?

Accepted Answer

$$0.2 \mu	ext{m}$$

Question 11

Which of the following is NOT a correct safety procedure before starting a microbiology lab?

Accepted Answer

Wearing open-toed shoes

Question 12

Which part of the microscope should you use first to bring a specimen into focus under low power?

Accepted Answer

Coarse focus knob

Question 13

After using the oil immersion lens, what is the correct procedure before putting away the microscope?

Accepted Answer

Clean the 100x objective lens

Question 14

Which of the following statements about binomial nomenclature is TRUE?

Accepted Answer

The genus name is capitalized and the species name is lowercase

Question 15

Which of the following best describes a parfocal microscope?

Accepted Answer

It remains nearly in focus when switching between objective lenses

Question 16

Which of the following is the correct order of taxonomic classification from most inclusive to least inclusive?

Accepted Answer

Domain, Kingdom, Phylum, Class, Order, Family, Genus, Species

Question 17

A student observes a specimen under the 4x objective and wants to switch to the 100x oil immersion objective. What is the correct sequence of steps?

Accepted Answer

Focus under 4x, then 10x, then 40x, add immersion oil, then switch to 100x

Question 18

Which of the following best explains why magnification without adequate resolution is meaningless in microscopy?

Accepted Answer

The image will appear larger but not clearer

Question 19

Which of the following is the correct abbreviation for Escherichia coli after its first mention in a scientific paper?

Accepted Answer

$$	extit{E. coli}$$

Question 20

Which of the following is the best reason for adjusting the iris diaphragm when viewing a specimen?

Accepted Answer

To improve contrast

Microbiology Lab Introduction Study Guide

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