Question 1

Which of the following statements best explains why penicillin is more effective against gram-positive bacteria than gram-negative bacteria?

Accepted Answer

Gram-positive bacteria have a thicker peptidoglycan layer, which is more susceptible to penicillin's inhibition of peptide bridge formation.

Question 2

A bacterium is observed to move in a corkscrew motion and is found to possess axial filaments. Which genus is most likely being observed?

Accepted Answer

Spirochete

Question 3

Which of the following best describes the function of the glycocalyx in pathogenic bacteria?

Accepted Answer

It prevents phagocytosis and helps bacteria adhere to body surfaces.

Question 4

A scientist isolates a cell with the following characteristics: paired chromosomes in a nuclear membrane, presence of histones, and membrane-bound organelles. What type of cell is this?

Accepted Answer

Eukaryotic cell

Question 5

Which of the following structures is responsible for the selective permeability of the bacterial plasma membrane?

Accepted Answer

Phospholipid bilayer

Question 6

A patient is infected with a bacterium that is resistant to desiccation, heat, and radiation, and can survive for thousands of years in a dormant state. Which structure is responsible for this resistance?

Accepted Answer

Endospore

Question 7

Which of the following is a function of the bacterial cell wall?

Accepted Answer

Prevents osmotic lysis

Question 8

Which process requires both a transporter protein and ATP to move substances against their concentration gradient?

Accepted Answer

Active transport

Question 9

Which of the following statements about the endosymbiotic theory is correct?

Accepted Answer

Mitochondria and chloroplasts originated from engulfed prokaryotic cells.

Question 10

A bacterium is found to have a thin peptidoglycan layer, an outer membrane containing lipopolysaccharide (LPS), and four rings in the basal body of its flagella. What type of cell wall does it have?

Accepted Answer

Gram-negative

Question 11

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 and have sterols in their plasma membrane.

Question 12

Which of the following is a distinguishing feature of eukaryotic ribosomes compared to prokaryotic ribosomes?

Accepted Answer

Eukaryotic ribosomes are 80S, while prokaryotic ribosomes are 70S.

Question 13

A bacterium is observed to form biofilms and adhere to surfaces in the human body. Which structure is most directly involved in this process?

Accepted Answer

Fimbriae

Question 14

Which of the following best describes the arrangement of microtubules in eukaryotic flagella and cilia?

Accepted Answer

9 pairs in a ring plus 2 in the center (9 + 2 array)

Question 15

Which of the following is a function of the Golgi complex in eukaryotic cells?

Accepted Answer

Modifies and transports proteins from the endoplasmic reticulum

Question 16

Which of the following best explains why lysozyme is effective against gram-positive bacteria?

Accepted Answer

Lysozyme hydrolyzes bonds in the glycan portion of peptidoglycan, weakening the cell wall.

Question 17

Which of the following is a real-world consequence of the presence of endospores in Bacillus and Clostridium species for the food industry?

Accepted Answer

Endospores can survive standard food processing, leading to potential foodborne illness.

Question 18

Which of the following best describes group translocation in bacteria?

Accepted Answer

A substance is chemically altered as it is transported into the cell, requiring phosphoenolpyruvic acid (PEP).

Question 19

Which of the following is a correct pairing of bacterial shape and arrangement?

Accepted Answer

Streptobacilli: chains of rod-shaped cells

Question 20

Which of the following statements about the plasma membrane is correct?

Accepted Answer

It is described by the fluid mosaic model, where proteins and phospholipids move laterally.

Functional Anatomy of Prokaryotic and Eukaryotic Cells: Microbiology Study Notes

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