Question 1

Which of the following statements best distinguishes growth from reproduction in living organisms?

Accepted Answer

Growth is the process of increasing in size, whereas reproduction is the process of producing new individuals.

Question 2

A scientist isolates a microorganism with the following characteristics: it has a thick cell wall containing teichoic acid, no outer membrane, and appears purple after Gram staining. Which type of cell is this organism most likely to be?

Accepted Answer

Gram-positive bacterium

Question 3

Which of the following best explains why Lipid A, a component of lipopolysaccharide (LPS) in Gram-negative bacteria, is considered dangerous even after the bacteria are killed?

Accepted Answer

Lipid A acts as an endotoxin, triggering immune responses such as fever and shock.

Question 4

A patient is infected with a bacterium that is highly resistant to penicillin and tetracycline. Which structural feature of the bacterium most likely contributes to this resistance?

Accepted Answer

Presence of porins in the outer membrane

Question 5

Which of the following best describes the mechanism by which bacterial flagella rotate?

Accepted Answer

Hydrogen ions passing through Mot proteins cause the basal rings to spin due to alternating charges.

Question 6

Which of the following arrangements of flagella would you expect to find on a bacterium that has a single flagellum at each end of the cell?

Accepted Answer

Amphitrichous

Question 7

A researcher observes a bacterial cell moving toward a chemical attractant. Which term best describes this type of movement?

Accepted Answer

Positive chemotaxis

Question 8

During conjugation, bacteria use which structure to exchange genetic material, and what is the typical form of DNA transferred?

Accepted Answer

Pili; plasmid DNA

Question 9

Which of the following transport processes requires energy and moves substances against their concentration gradient?

Accepted Answer

Active transport

Question 10

A bacterial cell is placed in a hypertonic solution. Predict what will happen to the cell and explain why, using the concept of osmosis.

Accepted Answer

Water will leave the cell, causing it to shrink, because the solute concentration is higher outside the cell.

Question 11

Which of the following statements about prokaryotic ribosomes is correct?

Accepted Answer

They are 70S, composed of 50S and 30S subunits.

Question 12

Which of the following features is unique to archaeal cell membranes compared to bacterial cell membranes?

Accepted Answer

Hydrocarbons attached to glycerol by ether bonds

Question 13

A scientist is studying a eukaryotic cell and observes that it contains a cell wall made of chitin. Which type of organism is this cell most likely from?

Accepted Answer

Fungus

Question 14

Which of the following best describes the function of the Golgi body in eukaryotic cells?

Accepted Answer

Processes and packages proteins received from the rough endoplasmic reticulum

Question 15

Which of the following is a correct statement about the cytoskeleton in eukaryotic cells?

Accepted Answer

Intermediate filaments are made of keratin and provide structural support.

Question 16

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

Accepted Answer

They have 70S ribosomes and their own circular DNA.

Question 17

A eukaryotic cell is observed to engulf a large particle by surrounding it with its membrane and forming a vesicle. Which process is being described, and what is the main function?

Accepted Answer

Phagocytosis; ingestion of large particles or cells

Question 18

Which of the following best explains why biofilms are more resistant to antibiotics than planktonic (free-living) bacteria?

Accepted Answer

Biofilms contain many porous layers and produce protective substances through quorum sensing.

Question 19

Which of the following correctly matches the eukaryotic ribosome with its subunits?

Accepted Answer

80S ribosome: 60S and 40S subunits

Question 20

A bacterium is exposed to harsh conditions such as heat, UV radiation, and desiccation. Which structure allows it to survive, and what is a key feature of this structure?

Accepted Answer

Endospore; has a proteinaceous exosporium and is highly resistant

Cellular Structures and Functions in Microbiology

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