Question 1

Which of the following statements best describes the main structural difference between the cytoplasmic membranes of Bacteria and Archaea?

Accepted Answer

Bacteria have a phospholipid bilayer with fatty acid tails, while Archaea have a phospholipid bilayer with isoprenoid chains instead of fatty acids.

Question 2

A patient is diagnosed with a bacterial infection. The causative agent is found to lack a cell wall. Which genus is most likely responsible?

Accepted Answer

Mycoplasma

Question 3

Which component of the Gram-negative bacterial cell envelope is responsible for its strong inflammatory response in humans?

Accepted Answer

Lipid A of lipopolysaccharide (LPS)

Question 4

During osmosis, water moves across the cytoplasmic membrane according to which principle?

Accepted Answer

Water moves from a region of lower solute concentration (hypotonic) to higher solute concentration (hypertonic).

Question 5

Which of the following best explains why Gram-negative bacteria are often more resistant to antibiotics than Gram-positive bacteria?

Accepted Answer

The presence of an outer membrane with porins that restrict entry of many antibiotics.

Question 6

Which structure in prokaryotes is primarily responsible for motility and is powered by a proton gradient?

Accepted Answer

Flagella

Question 7

A scientist is studying a bacterial species that forms a biofilm on dental surfaces. Which structure is most critical for the initial attachment and biofilm formation?

Accepted Answer

Glycocalyx (slime layer or capsule)

Question 8

Which of the following is a key difference between prokaryotic and eukaryotic ribosomes?

Accepted Answer

Prokaryotic ribosomes are 70S (50S + 30S), while eukaryotic cytoplasmic ribosomes are 80S (60S + 40S).

Question 9

Which of the following best describes the function of bacterial pili?

Accepted Answer

Facilitate DNA transfer between cells during conjugation.

Question 10

A researcher is using the Gram stain to identify bacteria in a clinical sample. Which structural difference is most responsible for the differential staining?

Accepted Answer

Thickness and cross-linking of the peptidoglycan layer.

Question 11

Which of the following is true regarding endospores?

Accepted Answer

They are highly resistant to heat, desiccation, chemicals, and UV radiation.

Question 12

Which of the following best explains why mitochondria and chloroplasts are considered to have originated from prokaryotic cells?

Accepted Answer

They contain 70S ribosomes and circular DNA, similar to prokaryotes.

Question 13

Which of the following is a function of the periplasmic space in Gram-negative bacteria?

Accepted Answer

Nutrient degradation and electron transport.

Question 14

Which of the following best describes the process of binary fission in prokaryotes?

Accepted Answer

Asexual reproduction resulting in two genetically identical daughter cells.

Question 15

Which of the following is a unique feature of Archaea cell walls compared to Bacteria?

Accepted Answer

Lack of peptidoglycan.

Question 16

A mutation in a bacterium prevents the formation of the pentaglycine cross-bridges in its cell wall. Which type of bacteria would be most affected?

Accepted Answer

Gram-positive bacteria

Question 17

Which of the following best describes the role of the fluid mosaic model in the function of the cytoplasmic membrane?

Accepted Answer

It allows for selective permeability and dynamic movement of proteins and lipids.

Question 18

Which of the following is a real-world application of LPS (lipopolysaccharide) in biomedical research?

Accepted Answer

Inducing inflammation to study cytokine and chemokine responses.

Question 19

Which of the following best explains why antibiotics that target 70S ribosomes are selectively toxic to bacteria?

Accepted Answer

Bacterial ribosomes are 70S, while eukaryotic cytoplasmic ribosomes are 80S.

Question 20

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

Accepted Answer

Protection from phagocytosis and desiccation.

Cell Structure and Function in Prokaryotes and Eukaryotes

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