Q: What is the total magnification when using a 10X ocular lens and a 40X objective lens on a compound microscope?

Total magnification $$= 10 \times 40 = 400$$

Question 1

Which biosafety level is appropriate for work with agents that pose a moderate potential hazard to personnel and the environment, and requires limited access, PPE, and biosafety cabinets for procedures with potential aerosol generation?

Accepted Answer

Biosafety Level 2

Question 2

A student accidentally splashes a bacterial culture onto their skin. Which route of exposure does this represent, and which safety rule is designed to minimize this risk?

Accepted Answer

Skin contact; wearing gloves and lab coats

Question 3

Which of the following items should be discarded in a biohazard waste container, NOT in the regular trash?

Accepted Answer

Used gloves

Question 4

When transporting inoculated petri plates to the incubator, which procedure should be followed to minimize contamination and exposure?

Accepted Answer

Stack plates and carry them with both hands, lids securely in place

Question 5

Which information should be included on a specimen label for a test tube in a microbiology lab?

Accepted Answer

Name, date, organism, and experiment number

Question 6

Where should agar plates be labeled to ensure proper identification and minimize confusion?

Accepted Answer

On the bottom of the plate

Question 7

What is the total magnification when using a 10X ocular lens and a 40X objective lens on a compound microscope?

Accepted Answer

Total magnification $$= 10 	imes 40 = 400$$

Question 8

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

Accepted Answer

To reduce light scattering and increase resolution

Question 9

Which bacterial cell morphology and arrangement would you expect to see as 'chains of spherical cells' under the microscope?

Accepted Answer

Streptococcus

Question 10

A micropipette labeled 'P1000' is best suited for measuring which volume range?

Accepted Answer

100–1000 $$\muL$$

Question 11

You need to measure 85 $$\muL of a $$solution. Which micropipette should you use?

Accepted Answer

P100

Question 12

If a micropipette window reads '085', what volume is it set to dispense?

Accepted Answer

85 $$\muL$$

Question 13

When reading the volume in a serological pipette, which step is essential to ensure accuracy?

Accepted Answer

Read the volume at the bottom of the meniscus

Question 14

Which of the following best defines 'aseptic technique' in microbiology?

Accepted Answer

A set of practices to prevent contamination of samples and the environment

Question 15

What is the primary purpose of heat fixing a bacterial smear before staining?

Accepted Answer

To kill the bacteria and adhere them to the slide

Question 16

Which PPE is required in the lab classroom to minimize exposure to biological hazards?

Accepted Answer

Lab coat, gloves, and safety goggles

Question 17

A student needs to discard a contaminated glass slide. Where should it be disposed?

Accepted Answer

Sharps container

Question 18

Which biosafety level requires the use of positive pressure suits and is used for work with dangerous and exotic agents with a high risk of aerosol-transmitted infections?

Accepted Answer

Biosafety Level 4

Question 19

A bacterial smear is best described as:

Accepted Answer

A thin layer of bacteria spread on a microscope slide for staining

Question 20

Which of the following is a potential route of exposure in a microbiology laboratory, and what safety rule minimizes this risk?

Accepted Answer

Ingestion; not eating or drinking in the lab

Microbiology Lab Safety, Microscopy, Micropipettes, and Staining: Guided Study

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