Question 1

A news article describes a bacterium as a 'bacillus.' How can you determine if the author is referring to the genus or the shape of the bacterium?

Accepted Answer

If 'Bacillus' is capitalized and italicized, it refers to the genus; if not, it refers to the rod shape.

Question 2

Endospore formation in bacteria is called (a) _____________. It is initiated by (b) ___________. Formation of a new cell from an endospore is called (c) ______________. This process is triggered by (d)_____________. Which of the following correctly fills in the blanks?

Accepted Answer

(a) sporulation, (b) lack of nutrients, (c) germination, (d) favorable conditions

Question 3

Which diagram represents a gram-positive bacterium, and how can you tell?

Accepted Answer

Diagram (a), because it has a thick peptidoglycan layer and teichoic acids.

Question 4

Why does penicillin have little effect on most gram-negative bacteria?

Accepted Answer

The outer membrane of gram-negative bacteria prevents penicillin from reaching the peptidoglycan layer.

Question 5

Which cell wall component is toxic to humans and can cause fever and shock?

Accepted Answer

Lipopolysaccharide (LPS) in gram-negative bacteria

Question 6

What happens when a gram-positive bacterium is placed in distilled water and penicillin is added?

Accepted Answer

The cell will undergo osmotic lysis.

Question 7

What happens when a gram-negative bacterium is placed in distilled water and penicillin?

Accepted Answer

Water will move into the cell, but the outer membrane protects against lysis.

Question 8

Which of the following is FALSE about fimbriae?

Accepted Answer

They may be used for motility.

Question 9

Why are drugs that target cell wall synthesis particularly useful in treating bacterial infections?

Accepted Answer

Human cells lack peptidoglycan, so these drugs selectively target bacteria.

Question 10

What happens to protoplasts and spheroplasts when placed in a hypotonic solution?

Accepted Answer

They undergo osmotic lysis due to water influx.

Question 11

Which of the following best describes the cell wall of acid-fast bacteria?

Accepted Answer

Thick peptidoglycan layer with mycolic acids

Question 12

A 0.5-mm cell was initially identified as a protozoan but later found to be a gram-positive bacterium. What evidence would support its reclassification as a bacterium?

Accepted Answer

Presence of peptidoglycan in the cell wall and prokaryotic cell structure

Question 13

When E. coli cells are exposed to a hypertonic solution, they produce a transporter protein that moves $$K^+$$ into the cell. What is the value of this active transport?

Accepted Answer

It helps balance osmotic pressure and prevents plasmolysis.

Question 14

Clostridium botulinum is a strict anaerobe. How does it survive on plants and why are home-canned foods a common source of botulism?

Accepted Answer

It forms endospores that resist oxygen and survive harsh conditions; home-canning may not destroy endospores.

Question 15

A child’s bathwater is orange and red due to Acidithiobacillus bacteria, but the source water is clear. How did the bacteria get into the household water?

Accepted Answer

The bacteria formed biofilms or endospores in household pipes, allowing them to survive and multiply.

Question 16

Which of the following best describes what happens to a cell exposed to polymyxins that destroy phospholipids?

Accepted Answer

Intracellular contents will leak from the cell.

Question 17

Which of the following statements about mycoplasmas is correct?

Accepted Answer

They lack a cell wall and have sterols in their plasma membrane.

Question 18

Which equation best represents the osmotic pressure ($$\Pi) $$across a bacterial cell membrane?

Accepted Answer

$$\Pi = iMRT$$

Question 19

Which of the following is a key difference between gram-positive and gram-negative cell walls?

Accepted Answer

Gram-negative bacteria have an outer membrane containing lipopolysaccharide.

Functional Anatomy of Prokaryotic and Eukaryotic Cells: Study Guide

Study Guide - Practice Questions

Study Guide - Flashcards