Question 1

Which of the following statements best explains why certain antibiotics, such as tetracycline, selectively target bacterial cells without harming human cells?

Accepted Answer

Bacterial ribosomes are 70S, while human ribosomes are 80S, allowing antibiotics to specifically inhibit bacterial protein synthesis.

Question 2

A scientist discovers a microorganism with the following characteristics: a single circular chromosome, 70S ribosomes, and a cell wall containing peptidoglycan. Which group does this organism most likely belong to?

Accepted Answer

Bacteria

Question 3

Which of the following is NOT evidence supporting the endosymbiotic theory for the origin of mitochondria and chloroplasts?

Accepted Answer

Both are surrounded by a cell wall made of peptidoglycan.

Question 4

A patient is diagnosed with a bacterial infection caused by Streptococcus pyogenes. Based on its cellular arrangement, what is the most likely microscopic appearance of this bacterium?

Accepted Answer

Spherical cells arranged in chains

Question 5

Which of the following best describes the function of magnetosomes in certain bacteria?

Accepted Answer

They align the bacteria with Earth's magnetic field to help them find optimal environments.

Question 6

Which of the following cell types would you expect to find chlorophyll dissolved in internal membranes rather than in membrane-bound organelles?

Accepted Answer

Cyanobacteria

Question 7

A microbiologist is studying a microorganism that lacks a nucleus, has a disorganized cytoplasm, and contains 70S ribosomes. Which of the following is most likely true about this organism?

Accepted Answer

It is a prokaryote and lacks membrane-bound organelles.

Question 8

Which of the following best explains why animal cells are more susceptible to osmotic lysis than bacterial cells?

Accepted Answer

Animal cells lack a cell wall, while bacterial cells have a rigid cell wall containing peptidoglycan.

Question 9

Which of the following structures is responsible for packaging and sorting proteins and lipids in eukaryotic cells?

Accepted Answer

Golgi apparatus

Question 10

A researcher is examining a microorganism under the microscope. The organism is unicellular, has a nucleus, and contains chitin in its cell wall. Which group does this organism most likely belong to?

Accepted Answer

Fungi

Question 11

Which of the following best describes the main difference in chromosome organization between prokaryotes and eukaryotes?

Accepted Answer

Prokaryotes have a single circular DNA molecule, while eukaryotes have multiple linear chromosomes associated with histones.

Question 12

Which of the following is a correct match between a microorganism and its typical cell wall composition?

Accepted Answer

Fungi – chitin

Question 13

A bacterial cell is observed to have storage granules containing polyphosphate. What is the most likely function of these granules?

Accepted Answer

They serve as energy and phosphate reserves for the cell.

Question 14

Which of the following best explains why mitochondria and chloroplasts have both 70S and 80S ribosomes?

Accepted Answer

They originated from prokaryotic ancestors and retain 70S ribosomes, but the host cell contains 80S ribosomes.

Question 15

Which of the following scenarios best illustrates the application of the endosymbiotic theory in modern cell biology?

Accepted Answer

Observation that mitochondria replicate independently of the host cell and contain their own DNA.

Question 16

A bacterium is found to be resistant to multiple antibiotics due to genes located on small, circular DNA molecules separate from its chromosome. What are these DNA molecules called?

Accepted Answer

Plasmids

Question 17

Which of the following best describes the function of lysosomes in eukaryotic cells?

Accepted Answer

They contain digestive enzymes that break down waste materials and cellular debris.

Question 18

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

Accepted Answer

Spirilla – spiral-shaped

Question 19

A microbiologist is studying a microorganism that forms chains of rod-shaped cells. What is the correct term for this arrangement?

Accepted Answer

Streptobacillus

Question 20

Which of the following best explains why cyanobacteria are considered prokaryotes despite their ability to perform photosynthesis?

Accepted Answer

They lack membrane-bound organelles, including a nucleus, and have chlorophyll dissolved in membranes.

Cell Structure and Function: Prokaryotes and Eukaryotes in Microbiology

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