Question 1

Which scientist is credited with first observing microorganisms using a microscope he constructed himself?

Accepted Answer

Anton van Leeuwenhoek

Question 2

A patient is diagnosed with a bacterial infection. According to Koch’s postulates, which step is necessary to prove that a specific bacterium causes the disease?

Accepted Answer

The bacterium must be isolated from a diseased host and grown in pure culture.

Question 3

Which of the following is NOT considered a domain in the three-domain system of classification?

Accepted Answer

Animalia

Question 4

During the Gram stain procedure, what is the correct order of reagents applied?

Accepted Answer

Crystal violet → iodine → alcohol-acetone → safranin

Question 5

A solution has a pH of 7.4. Which of the following best describes this solution?

Accepted Answer

It is slightly alkaline.

Question 6

Which of the following statements about bacterial cell walls is TRUE?

Accepted Answer

Gram-positive bacteria have a thick peptidoglycan layer and no outer membrane.

Question 7

Which of the following best describes the process of facilitated diffusion across a bacterial plasma membrane?

Accepted Answer

Movement of molecules from high to low concentration through a transport protein.

Question 8

A microbiologist wants to observe the internal structure of a virus particle. Which microscope should they use?

Accepted Answer

Transmission electron microscope (TEM)

Question 9

Which of the following is a function of the bacterial cell wall?

Accepted Answer

Protection against osmotic lysis

Question 10

A bacterial cell is placed in a 5% NaCl solution. What will happen to the cell?

Accepted Answer

Water will leave the cell, causing plasmolysis.

Question 11

Which of the following macromolecules is composed of amino acids and contains $$-NH_2$ (amino) groups?

Accepted Answer

Proteins

Question 12

Which of the following statements about endospores is CORRECT?

Accepted Answer

Endospores are dormant survival structures.

Question 13

Which of the following best describes the role of lysozyme in bacterial cells?

Accepted Answer

It damages or removes peptidoglycan from the cell wall.

Question 14

Which of the following is TRUE regarding the structure of triglycerides?

Accepted Answer

They are composed of glycerol and fatty acids.

Question 15

A scientist labels yeast proteins with $$^{35}S$$ and plasma membranes with $$^{32}P. $$Which macromolecule is being tracked with $$^{32}P$$?

Accepted Answer

Phospholipids

Question 16

Which of the following statements about the bacterial plasma membrane is INCORRECT?

Accepted Answer

It contains cholesterol.

Question 17

Which of the following best describes the process of hydrolysis?

Accepted Answer

Water is used to break a molecule apart.

Question 18

A bacterial cell lacking a cell wall is placed in a hypotonic solution. What is the most likely outcome?

Accepted Answer

The cell will undergo osmotic lysis.

Question 19

Which of the following best explains why immersion oil is used with the oil immersion objective lens in light microscopy?

Accepted Answer

It prevents the loss of light due to refraction, improving resolution.

Question 20

A microbiologist wants to visualize living, unstained cells and their internal structures. Which type of microscope should they use?

Accepted Answer

Phase-contrast microscope

Microbiology Chapters 1–4: Core Concepts and Rapid Review

Study Guide - Practice Questions

Study Guide - Flashcards