Question 1

Which of the following structures is found in all bacteria?

Accepted Answer

Ribosomes

Question 2

A bacterium is observed to have a thick peptidoglycan layer and teichoic acids. Which Gram reaction will it show, and what is a key clinical implication?

Accepted Answer

Gram-positive; more sensitive to penicillin

Question 3

Which of the following best describes the function of porin proteins in Gram-negative bacteria?

Accepted Answer

They act as selective channels for molecules to cross the outer membrane

Question 4

A patient is diagnosed with tuberculosis. Which unique cell wall component of Mycobacterium tuberculosis contributes to its resistance to drying and disinfectants?

Accepted Answer

Mycolic acid

Question 5

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

Accepted Answer

They possess an outer membrane that acts as a selective barrier

Question 6

Which bacterial structure is primarily responsible for the formation of biofilms on medical devices?

Accepted Answer

Fimbriae

Question 7

A bacterium with peritrichous flagella would be best described as:

Accepted Answer

Having flagella randomly distributed over the entire cell surface

Question 8

Which of the following is a correct statement about osmosis in bacteria?

Accepted Answer

In an isotonic solution, there is no net movement of water

Question 9

Which of the following drugs is specifically used to treat infections caused by MRSA (Methicillin-resistant Staphylococcus aureus)?

Accepted Answer

Vancomycin

Question 10

A patient presents with a persistent cough, fever, and weight loss. Acid-fast staining of sputum reveals red/pink rods. What is the most likely diagnosis?

Accepted Answer

Mycobacterium tuberculosis infection

Question 11

Which of the following best describes the mechanism of action of penicillin?

Accepted Answer

Inhibits the cross-linking of peptidoglycan in the cell wall

Question 12

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

Accepted Answer

Protects against phagocytosis by white blood cells

Question 13

Which of the following statements about bacterial endospores is FALSE?

Accepted Answer

They are easily destroyed by boiling water

Question 14

Which of the following best explains why Mycoplasma pneumoniae is resistant to penicillin?

Accepted Answer

It lacks a cell wall

Question 15

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

Accepted Answer

Lack of a membrane-bound nucleus

Question 16

A patient is diagnosed with a Gram-negative bacterial infection. Which of the following is a unique component of the outer membrane that can trigger fever and shock?

Accepted Answer

Lipopolysaccharide (LPS)

Question 17

Which of the following best describes the process of facilitated diffusion in bacteria?

Accepted Answer

Passive movement of substances along their concentration gradient with the help of membrane proteins

Question 18

Which of the following is a function of bacterial plasmids?

Accepted Answer

Confer protective traits such as antibiotic resistance

Question 19

Which of the following is the correct order of events in the primary stage of tuberculosis infection?

Accepted Answer

Bacillus inhaled → phagocytized by macrophages → tubercle formation → calcification

Question 20

Which of the following best describes the action of beta-lactamases in bacterial resistance?

Accepted Answer

They destroy the beta-lactam ring of antibiotics, rendering them ineffective

Prokaryotic Cell Structure, Antimicrobials, and Bacterial Respiratory Diseases

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