Question 1

Which of the following best describes the main structural difference between the cell walls of Gram-positive and Gram-negative bacteria?

Accepted Answer

Gram-positive bacteria have a thick peptidoglycan layer and teichoic acids, while Gram-negative bacteria have a thin peptidoglycan layer and an outer membrane containing lipopolysaccharides.

Question 2

A patient is diagnosed with a bacterial infection caused by a species that lacks a cell wall. Which of the following antibiotics would likely be ineffective against this organism, and why?

Accepted Answer

Penicillin, because it targets the synthesis of peptidoglycan, which is absent in bacteria without cell walls.

Question 3

Which of the following best explains why Gram-negative bacteria are generally less susceptible to penicillin than Gram-positive bacteria?

Accepted Answer

The outer membrane of Gram-negative bacteria blocks access of penicillin to its target in the peptidoglycan layer.

Question 4

A microbiologist observes a bacterium with a corkscrew shape and movement. Which structure is most likely responsible for its motility?

Accepted Answer

Axial filaments (endoflagella)

Question 5

Which of the following is a function of the bacterial glycocalyx?

Accepted Answer

It helps bacteria evade phagocytosis and adhere to surfaces, contributing to virulence.

Question 6

Which of the following best describes the process of group translocation in prokaryotic cells?

Accepted Answer

A substance is chemically modified as it is transported across the membrane, requiring a transporter protein and phosphoenolpyruvic acid (PEP).

Question 7

Which of the following inclusions would you expect to find in a photosynthetic bacterium that fixes carbon dioxide?

Accepted Answer

Carboxysomes

Question 8

A bacterial cell is placed in a hypertonic solution. What is the most likely outcome for the cell?

Accepted Answer

Water will move out of the cell, causing plasmolysis.

Question 9

Which of the following statements about prokaryotic ribosomes is correct?

Accepted Answer

They are 70S, composed of 50S and 30S subunits, and are the target of antibiotics like streptomycin.

Question 10

Which of the following is NOT a function of the prokaryotic plasma membrane?

Accepted Answer

Synthesis of peptidoglycan for the cell wall

Question 11

Which of the following best explains why endospores are a concern in the food industry?

Accepted Answer

Endospores are highly resistant to heat, chemicals, and desiccation, allowing them to survive food processing and cause spoilage or disease.

Question 12

Which of the following is a key piece of evidence supporting the endosymbiotic theory for the origin of mitochondria and chloroplasts?

Accepted Answer

They contain circular DNA and 70S ribosomes similar to those of bacteria.

Question 13

A bacterium is observed to have numerous hairlike appendages that allow it to adhere to surfaces and form biofilms. What are these structures called?

Accepted Answer

Fimbriae

Question 14

Which of the following best describes the arrangement of microtubules in a eukaryotic flagellum?

Accepted Answer

A 9 + 2 array of microtubules

Question 15

Which of the following is a correct comparison between prokaryotic and eukaryotic flagella?

Accepted Answer

Prokaryotic flagella are composed of flagellin and rotate, while eukaryotic flagella are composed of microtubules and move in a wavelike manner.

Question 16

Which of the following best describes the function of teichoic acids in Gram-positive bacteria?

Accepted Answer

They help regulate movement of cations and provide antigenic specificity.

Question 17

A scientist is studying a bacterium that can survive in extremely dry environments and is resistant to heat and radiation. Which structure is most likely responsible for these properties?

Accepted Answer

Endospore

Question 18

Which of the following best explains why mycoplasmas are resistant to antibiotics that interfere with cell wall synthesis?

Accepted Answer

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

Question 19

Which of the following is a correct statement about the nucleoid in prokaryotic cells?

Accepted Answer

It contains the cell's genetic material in a single circular DNA molecule not enclosed by a membrane.

Functional Anatomy of Prokaryotic and Eukaryotic Cells: Structure, Function, and Comparison

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