Question 1

Which of the following statements best explains why prokaryotic cells can couple transcription and translation, while eukaryotic cells cannot?

Accepted Answer

Prokaryotic cells lack a nuclear membrane, allowing ribosomes to access mRNA as it is being transcribed.

Question 2

A bacterium is observed to have a thick peptidoglycan layer and no outer membrane. Which type of cell envelope does it most likely possess?

Accepted Answer

Gram-positive

Question 3

Which of the following is a function of membrane proteins in prokaryotic cells?

Accepted Answer

Chemotaxis

Question 4

A scientist isolates a microorganism with the following features: phosphoglycerine-ether lipids, circular DNA, and 70S ribosomes. To which domain does this organism most likely belong?

Accepted Answer

Archaea

Question 5

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

Accepted Answer

It provides structural support and protects against osmotic pressure.

Question 6

During a Gram stain, a bacterium retains the crystal violet stain and appears purple under the microscope. What structural feature is responsible for this result?

Accepted Answer

A thick peptidoglycan layer in the cell wall

Question 7

Which of the following is NOT a typical component of the prokaryotic cytoplasm?

Accepted Answer

Mitochondria

Question 8

A bacterial cell is found to lack a cell wall. Which genus is it most likely to belong to?

Accepted Answer

Mycoplasma

Question 9

Which of the following best explains why lipopolysaccharide (LPS) is clinically significant in Gram-negative bacteria?

Accepted Answer

LPS can act as an endotoxin, triggering strong immune responses in humans.

Question 10

Which of the following correctly matches the domain with its typical cell membrane lipid structure?

Accepted Answer

Bacteria: phosphoglycerine-fatty acid ester

Question 11

A researcher discovers a prokaryote with a diameter of $$0.8\ \mu m$$, a single circular chromosome, and no membrane-bound organelles. Which of the following additional features would most strongly suggest it is a bacterium rather than an archaeon?

Accepted Answer

Presence of peptidoglycan in the cell wall

Question 12

Which of the following best describes the genetic material in most bacteria?

Accepted Answer

A single, double-stranded circular DNA molecule located in the nucleoid

Question 13

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

Accepted Answer

Gram-negative bacteria have an outer membrane containing lipopolysaccharide, while Gram-positive bacteria do not.

Question 14

Which of the following best explains why prokaryotic ribosomes are important targets for antibiotics?

Accepted Answer

Prokaryotic ribosomes (70S) differ structurally from eukaryotic ribosomes (80S), allowing selective inhibition.

Question 15

A patient is infected with a bacterium that is resistant to osmotic lysis. Which structural feature most likely provides this protection?

Accepted Answer

A rigid peptidoglycan cell wall

Question 16

Which of the following is a real-world consequence of the presence of lipopolysaccharide (LPS) in Gram-negative bacteria?

Accepted Answer

LPS can cause septic shock in patients with bloodstream infections.

Question 17

Which of the following best describes the function of plasmids in bacterial cells?

Accepted Answer

They carry extra-chromosomal genes that can confer advantages such as antibiotic resistance.

Question 18

A bacterial cell is observed to have simultaneous transcription and translation occurring on the same mRNA molecule. What is the name for the structure formed by multiple ribosomes translating a single mRNA?

Accepted Answer

Polysome

Question 19

Which of the following storage compounds is commonly found in the cytoplasm of prokaryotic cells?

Accepted Answer

Glycogen

Question 20

A microbiologist is studying a prokaryote that is rod-shaped and measures $$1.5\ \mu m in $$diameter. Which term best describes its shape?

Accepted Answer

Bacillus

The Prokaryotic Cell: Structure, Classification, and Function

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