Question 1

Which of the following best distinguishes a scientific theory from a hypothesis?

Accepted Answer

A scientific theory is a well-substantiated explanation supported by a large body of evidence and subject to ongoing testing and refinement, while a hypothesis is a testable, specific prediction.

Question 2

Which of the following statements is NOT a component of the Cell Theory?

Accepted Answer

All cells contain a nucleus.

Question 3

A scientist is examining a cell under a microscope and observes a highly detailed, three-dimensional image of the cell's surface. Which type of microscope is most likely being used?

Accepted Answer

Scanning electron microscope (SEM)

Question 4

Which of the following best describes the difference between magnification and resolution in microscopy?

Accepted Answer

Magnification increases the apparent size of an object, while resolution is the ability to distinguish two close points as separate.

Question 5

Why are cells generally small in size? Use the concept of surface area-to-volume ratio in your answer.

Accepted Answer

As cells increase in size, their volume grows faster than their surface area, reducing the surface area-to-volume ratio and limiting efficient diffusion of materials.

Question 6

A cell has a surface area of $ 150 \, \mathrm{\mu m}^2 $ and a volume of $ 50 \, \mathrm{\mu m}^3 $. What is its surface area-to-volume ratio?

Accepted Answer

$ 3:1 $

Question 7

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

Accepted Answer

Ribosomes

Question 8

Which of the following is a function of the prokaryotic capsule?

Accepted Answer

Protection from desiccation and immune system attack

Question 9

Which statement correctly describes the nucleoid in a prokaryotic cell?

Accepted Answer

It is the region where the cell's DNA is located, not surrounded by a membrane.

Question 10

Which of the following best explains why microvilli are present on the surface of intestinal epithelial cells?

Accepted Answer

They increase the surface area for absorption of nutrients.

Question 11

Which of the following is NOT a function of the smooth endoplasmic reticulum (Smooth ER)?

Accepted Answer

Protein folding and modification

Question 12

A mutation prevents the formation of vesicles in a cell. Which process would be most directly affected?

Accepted Answer

Transport of proteins from the endoplasmic reticulum to the Golgi apparatus

Question 13

Which organelle is responsible for modifying, sorting, and shipping proteins and lipids received from the endoplasmic reticulum?

Accepted Answer

Golgi apparatus

Question 14

Which of the following best describes the function of lysosomes?

Accepted Answer

They contain digestive enzymes that break down macromolecules and recycle cellular components.

Question 15

Which statement correctly differentiates peroxisomes from lysosomes?

Accepted Answer

Peroxisomes break down fatty acids and detoxify harmful substances, producing hydrogen peroxide as a byproduct.

Question 16

Which of the following statements about mitochondria and chloroplasts is TRUE?

Accepted Answer

Both contain their own DNA and ribosomes, supporting the endosymbiotic theory.

Question 17

A muscle cell contracts by sliding actin filaments past myosin. Which cytoskeletal component is directly involved in this process?

Accepted Answer

Actin filaments

Question 18

Which of the following best describes the function of tight junctions in animal tissues?

Accepted Answer

They form a waterproof seal between adjacent cells, preventing leakage of extracellular fluid.

Question 19

A plant cell is able to communicate with its neighboring cells by passing ions and small molecules through open channels. What are these channels called?

Accepted Answer

Plasmodesmata

Question 20

Which of the following best explains why the spindle apparatus is essential during cell division?

Accepted Answer

It is composed of microtubules that separate chromosomes into daughter cells.

Cell Structure and Function: Study Guide

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