Question 1

Which of the following statements best explains why prokaryotic cells are generally smaller than eukaryotic cells?

Accepted Answer

Prokaryotic cells do not have membrane-bound organelles, so all cellular processes occur in the cytoplasm, limiting their size due to surface area-to-volume constraints.

Question 2

A scientist is examining a cell under a microscope and observes that the DNA is located in a nucleoid region and the cell lacks membrane-bound organelles. Which type of cell is being observed?

Accepted Answer

Prokaryotic cell

Question 3

Which of the following best describes the difference in DNA structure between prokaryotic and eukaryotic cells?

Accepted Answer

Prokaryotic cells have circular DNA, while eukaryotic cells have linear DNA.

Question 4

Which of the following is a unique feature of cyanobacteria compared to other photosynthetic prokaryotes?

Accepted Answer

They have thylakoid membranes where photosynthesis occurs.

Question 5

During Gram staining, what is the primary reason that Gram-positive bacteria retain the crystal violet-iodine complex after ethanol treatment?

Accepted Answer

The thick peptidoglycan layer is dehydrated by ethanol, trapping the crystal violet-iodine complex inside.

Question 6

Which of the following best describes the function of Gram’s iodine in the Gram staining procedure?

Accepted Answer

It acts as a mordant, forming a complex with crystal violet to help it remain in Gram-positive cells.

Question 7

A bacterial sample is stained and observed to be pink under the microscope after Gram staining. Which of the following best explains this result?

Accepted Answer

The bacteria are Gram-negative, with a thin peptidoglycan layer and an outer membrane that is dissolved by ethanol, allowing the safranin to stain the cells pink.

Question 8

Which of the following best describes an autotroph?

Accepted Answer

An organism that produces its own food, usually using energy from the sun.

Question 9

Which bacterial morphology is described as helical or spiral shaped?

Accepted Answer

Spirillum

Question 10

A microbiologist wants to isolate a single bacterial colony from a mixed culture. Which technique should they use?

Accepted Answer

4-quadrant streak plate

Question 11

Which of the following is true about the storage of genetic material in prokaryotic cells?

Accepted Answer

DNA is found in the nucleoid region and is circular.

Question 12

Which of the following statements about bacterial cell walls is correct?

Accepted Answer

Both Gram-positive and Gram-negative bacteria have a peptidoglycan layer, but only Gram-negative bacteria have an outer membrane.

Question 13

Which of the following best explains why safranin is used in the Gram staining procedure?

Accepted Answer

It stains Gram-negative bacteria pink after the crystal violet-iodine complex is washed out.

Question 14

Which of the following is NOT a characteristic of prokaryotic cells?

Accepted Answer

Presence of membrane-bound organelles

Question 15

A student observes a green, filamentous organism under the microscope that lacks chloroplasts but has thylakoid membranes. What is the most likely identity of this organism?

Accepted Answer

Cyanobacteria

Question 16

Which of the following best describes the role of ethanol in the Gram staining procedure?

Accepted Answer

It acts as a decolorizing agent, removing the crystal violet-iodine complex from Gram-negative bacteria.

Question 17

Which of the following is a correct sequence of steps in the Gram staining procedure?

Accepted Answer

Crystal violet, Gram’s iodine, ethanol, safranin

Question 18

Which of the following best explains why glass slides should be gently passed through a flame rather than held in the flame during heat fixing?

Accepted Answer

To avoid breaking the glass due to rapid heating.

Question 19

Which of the following is a real-world application of the spread plate/lawn plate technique?

Accepted Answer

Creating a uniform surface of bacterial growth to test antibiotic effectiveness.

Question 20

Which of the following equations best represents the relationship between surface area and volume as a cell increases in size, and why is this important for prokaryotic cells?

Accepted Answer

$$	ext{Surface Area} = 4\pi r^2$, $$	ext{Volume} = \frac{4}{3}\pi $$r^3$$; as cell size increases, volume increases faster than surface area, limiting nutrient exchange in larger prokaryotic cells.

Prokaryotic Cells: Structure, Function, and Laboratory Techniques

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