Question 1

Which of the following best explains why cells are typically small in size?

Accepted Answer

Smaller cells have a higher surface area to volume ratio, which facilitates efficient exchange of materials with their environment.

Question 2

A spherical cell has a radius of $$r = 2\ \mu m. $$What is its surface area to volume ratio? (Surface area of a sphere: $$4\pi r^2$, Volume: $$\frac{4}{3}\pi $$r^3)$$

Accepted Answer

$$\frac{3}{r}$$

Question 3

Which of the following structures is found in both prokaryotic and eukaryotic cells?

Accepted Answer

Ribosomes

Question 4

A scientist is studying a cell with the following characteristics: a nucleoid region, circular DNA, and a cell wall made of peptidoglycan. Which type of cell is this most likely to be?

Accepted Answer

Bacterial cell

Question 5

According to the endosymbiont theory, which organelles in eukaryotic cells are believed to have originated from free-living prokaryotes?

Accepted Answer

Mitochondria and chloroplasts

Question 6

Which of the following statements about the nuclear envelope is correct?

Accepted Answer

It consists of two lipid bilayers and contains nuclear pores for transport.

Question 7

A mutation disrupts the nuclear lamina in a eukaryotic cell. Which of the following is the most likely consequence?

Accepted Answer

The nucleus loses its structural shape and may collapse.

Question 8

Which of the following best describes the function of the nucleolus?

Accepted Answer

It assembles ribosomal RNA and ribosomal subunits.

Question 9

Which of the following is a key difference between the DNA of prokaryotes and eukaryotes?

Accepted Answer

Prokaryotic DNA is circular and not associated with histones, while eukaryotic DNA is linear and associated with histones.

Question 10

A researcher introduces a recombinant plasmid containing an antibiotic resistance gene into E. coli. What is the primary purpose of including the antibiotic resistance gene?

Accepted Answer

To select for bacteria that have successfully taken up the plasmid by growing them in the presence of the antibiotic.

Question 11

Which of the following statements about the endomembrane system is correct?

Accepted Answer

It includes the nuclear envelope, endoplasmic reticulum, Golgi apparatus, lysosomes, and vesicles.

Question 12

Which of the following best describes the main structural component of plant cell walls?

Accepted Answer

Cellulose

Question 13

A fungal cell is observed to have a rigid cell wall. Which molecule is primarily responsible for this rigidity?

Accepted Answer

Chitin

Question 14

Which of the following is NOT a function of the cytoskeleton in eukaryotic cells?

Accepted Answer

Synthesizing DNA during replication

Question 15

Which of the following best describes the relationship between the extracellular matrix (ECM) and the cytoskeleton in animal cells?

Accepted Answer

The ECM is linked to the cytoskeleton via integrin proteins, allowing communication between the cell's exterior and interior.

Question 16

Which of the following types of cellular junctions is primarily responsible for preventing the leakage of extracellular fluid between animal cells?

Accepted Answer

Tight junctions

Question 17

A cell is observed to have multiple nucleoli. What does this suggest about the cell's activity?

Accepted Answer

It is actively producing ribosomes and likely engaged in high levels of protein synthesis.

Question 18

Which of the following best explains why the surface area to volume ratio decreases as a cell grows larger?

Accepted Answer

Surface area increases by the square of the radius, while volume increases by the cube of the radius.

Question 19

Which of the following is a real-world application of plasmids in biotechnology?

Accepted Answer

Producing large quantities of a specific protein, such as insulin, by inserting the gene into bacteria.

Question 20

Which of the following best describes the process by which the endomembrane system is thought to have evolved in eukaryotes?

Accepted Answer

Invagination of the plasma membrane formed internal compartments such as the nucleus and endoplasmic reticulum.

Cell Structure: Principles, Types, and Functions

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