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 thick peptidoglycan layer that is easily penetrated by penicillin, which inhibits peptide bridge formation.

Question 2

A bacterium is observed to move toward a glucose source. Which structure is primarily responsible for this movement, and what is the process called?

Accepted Answer

Flagella; chemotaxis

Question 3

Which of the following best describes the composition of the bacterial cell wall in Archaea?

Accepted Answer

Pseudomurein lacking N-acetylmuramic acid (NAM) and D-amino acids

Question 4

A patient is infected with a bacterium that resists phagocytosis and forms biofilms on medical devices. Which structure is most likely responsible for these properties?

Accepted Answer

Glycocalyx (capsule and slime layer)

Question 5

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

Accepted Answer

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

Question 6

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

Accepted Answer

Active transport

Question 7

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 plasmolysis.

Question 8

Which of the following structures is involved in the transfer of DNA between bacterial cells during conjugation?

Accepted Answer

Pili

Question 9

Which of the following is NOT a function of the plasma (cytoplasmic) membrane in prokaryotes?

Accepted Answer

Synthesis of peptidoglycan

Question 10

Which of the following statements about endospores is TRUE?

Accepted Answer

Endospores are highly resistant to heat, desiccation, chemicals, and radiation.

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 characteristic of gram-negative bacterial cell walls?

Accepted Answer

Presence of an outer membrane containing lipopolysaccharide (LPS)

Question 13

Which of the following is a function of teichoic acids in gram-positive bacteria?

Accepted Answer

Regulation of cation movement and providing antigenic specificity

Question 14

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

Accepted Answer

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

Question 15

Which of the following is evidence supporting the endosymbiotic theory for the origin of mitochondria and chloroplasts?

Accepted Answer

They contain circular DNA and 70S ribosomes.

Question 16

A scientist observes a bacterium with a single flagellum at each end. What is the correct term for this flagellar arrangement?

Accepted Answer

Amphitrichous

Question 17

Which of the following best describes the function of carboxysomes in prokaryotic cells?

Accepted Answer

They contain the enzyme RuBisCO for CO$$_2$$ fixation during photosynthesis.

Question 18

Which of the following statements about facilitated diffusion is TRUE?

Accepted Answer

It requires a transporter protein but does not require energy.

Question 19

Which of the following is a function of the glycocalyx in eukaryotic animal cells?

Accepted Answer

Strengthening the cell surface and aiding in cell–cell recognition

Question 20

Which of the following best describes the process of group translocation in prokaryotes?

Accepted Answer

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

Functional Anatomy of Prokaryotic and Eukaryotic Cells: Microbiology Study Notes

Guida di studio - Domande di pratica

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