Question 1

Which of the following is a characteristic that distinguishes prokaryotic cells from eukaryotic cells?

Accepted Answer

One circular chromosome not in a membrane

Question 2

A scientist observes a microbe that is 0.8 µm in diameter, lacks a nucleus, and has a cell wall containing peptidoglycan. Which domain does this organism most likely belong to?

Accepted Answer

Bacteria

Question 3

Which of the following best describes the function of the bacterial glycocalyx capsule?

Accepted Answer

It prevents the cell from being recognized and destroyed by host immune cells.

Question 4

Which of the following statements about Gram-negative bacteria is correct?

Accepted Answer

They have a thin peptidoglycan layer and an outer membrane containing lipopolysaccharide (LPS).

Question 5

Which process is responsible for the movement of water across a selectively permeable membrane from an area of high water concentration to an area of lower water concentration?

Accepted Answer

Osmosis

Question 6

A bacterium 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 it to shrink.

Question 7

Which of the following is a function of bacterial fimbriae?

Accepted Answer

Attachment to surfaces and formation of biofilms

Question 8

Which chemical component is unique to the cell walls of Gram-positive bacteria?

Accepted Answer

Teichoic acids

Question 9

Which of the following best explains why Mycoplasma species are resistant to antibiotics that target cell wall synthesis?

Accepted Answer

They lack a cell wall entirely.

Question 10

Which of the following is a correct description of group translocation in bacteria?

Accepted Answer

It requires a transporter protein and phosphoenolpyruvic acid (PEP), and the substance is chemically modified during transport.

Question 11

Which of the following structures is responsible for the corkscrew motility observed in spirochetes?

Accepted Answer

Axial filaments (endoflagella)

Question 12

Which of the following statements about endospores is true?

Accepted Answer

They are resistant to extreme conditions such as heat, radiation, and chemicals.

Question 13

Which of the following best describes the function of the bacterial cytoplasmic membrane?

Accepted Answer

It acts as a selectively permeable barrier and is involved in energy production.

Question 14

Which of the following is a correct pairing of a bacterial cell wall component and its function?

Accepted Answer

N-acetylmuramic acid (NAM): provides sites for peptide cross-linking

Question 15

A patient is infected with a bacterium that stains red after Gram staining. Which of the following statements is most likely true about this bacterium?

Accepted Answer

It has an outer membrane containing lipopolysaccharide (LPS).

Question 16

Which of the following best explains why Bacillus anthracis can survive in mail during a bioterrorist attack?

Accepted Answer

It forms endospores that are resistant to harsh environmental conditions.

Question 17

Which of the following is NOT a characteristic of life found in viruses?

Accepted Answer

Growth

Question 18

Which of the following best supports the endosymbiotic theory of eukaryotic evolution?

Accepted Answer

Mitochondria and chloroplasts contain their own DNA and resemble bacteria.

Question 19

Which of the following is a correct description of the Gram stain mechanism?

Accepted Answer

Alcohol dehydrates the thick peptidoglycan layer in Gram-positive cells, trapping the crystal violet-iodine complex.

Question 20

Which of the following is a function of bacterial plasmids?

Accepted Answer

They carry non-crucial genes such as antibiotic resistance.

Cell Structure and Function in Microbiology

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