Who was the first person to observe microorganisms?

• Robert Hooke

• Carl Zeiss

• Hans Janssen

• Anton van Leeuwenhoek

What is the primary function of the objective lens in a microscope?

• To focus the light

• To provide illumination

• To adjust the resolution

• To produce a magnified image

What does resolving power refer to in microscopy?

• The ability to magnify an image

• The ability to illuminate a specimen

• The ability to distinguish two points

• The ability to color the specimen

What is the purpose of immersion oil in microscopy?

• To enhance color contrast

• To reduce the size of the field of view

• To increase the objective lens diameter

• To magnify the specimen

Which type of microscope produces a dark image against a brighter background?

• Bright-field microscope

• Phase-contrast microscope

• Dark-field microscope

• Fluorescence microscope

What is the main purpose of Gram staining?

• To observe living cells

• To enhance contrast in microscopy

• To differentiate bacteria based on cell wall constituents

• To identify the shape of bacteria

What happens during heat fixation in Gram staining?

• Cells are dried with blotting paper

• Cells are decolorized with ethanol

• Cells are coagulated to stick to the slide

• Cells are stained with crystal violet

What color do Gram-positive bacteria appear after Gram staining?

• Red

• Green

• Violet

• Blue

What is the role of KOH in the KOH test?

• To fix the bacteria to the slide

• To break down Gram-negative cell walls

• To stain the bacteria

• To enhance the resolution

What is the main purpose of endospore staining?

• To observe cell morphology

• To differentiate between living and dead cells

• To identify spore formers from non-spore formers

• To enhance color contrast