Question 1

Which of the following best describes Koch's postulates and their significance in microbiology?

Accepted Answer

They are a set of criteria used to establish a causative relationship between a microbe and a disease.

Question 2

A microbiologist is using a differential stain to distinguish between two types of bacteria. Which stain is most likely being used, and what is the primary difference it reveals?

Accepted Answer

Gram stain; it differentiates bacteria based on differences in cell wall structure.

Question 3

Which of the following best explains the difference between prokaryotic and eukaryotic cells?

Accepted Answer

Prokaryotic cells lack a membrane-bound nucleus, while eukaryotic cells have a membrane-bound nucleus.

Question 4

A patient sample is Gram-stained and observed under a microscope. The cells appear purple. What does this indicate about the bacterial cell wall?

Accepted Answer

The bacteria are Gram-positive and have a thick peptidoglycan layer.

Question 5

Which of the following is NOT a function of bacterial endospores?

Accepted Answer

Facilitating rapid reproduction during favorable conditions.

Question 6

A microbiologist is studying a microbe that thrives at temperatures above $80^\circ$C and acidic pH. Which term best describes this organism?

Accepted Answer

Thermoacidophile

Question 7

Which of the following best describes the fluid mosaic model of the cell membrane?

Accepted Answer

A dynamic structure with proteins embedded in or attached to a phospholipid bilayer.

Question 8

Which of the following best distinguishes an integral membrane protein from a peripheral membrane protein?

Accepted Answer

Integral proteins span the lipid bilayer, while peripheral proteins are attached to the membrane surface.

Question 9

A cyanobacterium that performs photosynthesis and uses carbon dioxide as its carbon source is best classified as which of the following?

Accepted Answer

Photoautotroph

Question 10

Which of the following statements about bacterial flagella is correct?

Accepted Answer

Bacterial flagella are composed of flagellin and rotate to propel the cell.

Question 11

Which of the following best describes the difference between taxonomy and phylogeny?

Accepted Answer

Taxonomy is the classification and naming of organisms, while phylogeny is the study of evolutionary relationships.

Question 12

Which of the following is a correct statement about viruses?

Accepted Answer

Viruses lack cellular structure and require a host cell to replicate.

Question 13

A microbiologist is using a defined (synthetic) medium to culture bacteria. Which of the following best describes this type of medium?

Accepted Answer

All chemical components and their concentrations are known.

Question 14

Which of the following best explains why some microbes are considered 'unculturable' in the laboratory?

Accepted Answer

They require specific growth factors or conditions not provided in standard media.

Question 15

Which of the following is a correct match between a bacterial cell shape and its description?

Accepted Answer

Bacillus: rod-shaped

Question 16

A researcher is studying bacteriophages. Which of the following statements is true about their life cycles?

Accepted Answer

Bacteriophages can undergo both lytic and lysogenic cycles.

Question 17

Which of the following best describes the function of an endospore in bacteria?

Accepted Answer

It allows the bacterium to survive harsh environmental conditions.

Question 18

Which of the following is a correct example of a differential/selective medium and its use?

Accepted Answer

MacConkey agar; it differentiates lactose fermenters and selects for Gram-negative bacteria.

Question 19

Which of the following best describes the main difference between archaea and bacteria?

Accepted Answer

Archaea have unique membrane lipids and lack peptidoglycan in their cell walls.

Question 20

A scientist is studying a microbe that can only be detected using DNA sequencing, not by culturing on standard media. What is the most likely reason for this?

Accepted Answer

The microbe is unculturable due to specific growth requirements not met in the lab.

Core Concepts in Microbiology: Study Guide for Lectures 2–7

Study Guide - Practice Questions

Study Guide - Flashcards