$\text{Water moves from}~[H_2O]_{high}~\text{to}~[H_2O]_{low}$

Question 1

Which component of the plasma membrane is primarily responsible for its selective permeability?

Accepted Answer

Phospholipids, because their hydrophobic and hydrophilic regions create a barrier to most substances.

Question 2

A cell is placed in a hypertonic solution. What will happen to the cell, and why?

Accepted Answer

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

Question 3

Which organelle is responsible for producing ATP, and what structural feature enables this function?

Accepted Answer

Mitochondria; the presence of cristae increases surface area for ATP synthesis.

Question 4

During protein synthesis, which process occurs first and where does it take place?

Accepted Answer

Transcription in the nucleus.

Question 5

Which equation best represents the movement of water during osmosis?

Accepted Answer

$	ext{Water moves from}~[H_2O]_{high}~	ext{to}~[H_2O]_{low}$

Question 6

A patient receives an intravenous solution that is hypotonic compared to their blood plasma. What is the most likely cellular response?

Accepted Answer

Cells will gain water and swell.

Question 7

Which organelle is most directly involved in the synthesis of lipids such as cholesterol?

Accepted Answer

Smooth endoplasmic reticulum

Question 8

What is the main function of the Golgi complex in a cell?

Accepted Answer

Collecting, sorting, packaging, and distributing proteins and lipids

Question 9

Which of the following best describes the role of carrier proteins in facilitated diffusion?

Accepted Answer

They allow molecules to move down their concentration gradient without using energy.

Question 10

Which process requires energy input from the cell and moves substances from low to high concentration?

Accepted Answer

Active transport

Question 11

A cell is actively engulfing bacteria. Which process is being used?

Accepted Answer

Phagocytosis

Question 12

Which structure is responsible for producing ribosomes?

Accepted Answer

Nucleolus

Question 13

What is the function of microvilli on the surface of intestinal cells?

Accepted Answer

To increase surface area for absorption

Question 14

Which stage of mitosis is characterized by the alignment of chromosomes along the center of the cell?

Accepted Answer

Metaphase

Question 15

Which equation best represents the sodium-potassium pump activity in active transport?

Accepted Answer

$3~Na^+_{out}~:~2~K^+_{in}~+~ATP \rightarrow ADP~+~P_i$

Question 16

Which cytoskeletal element is primarily involved in cell movement and muscle contraction?

Accepted Answer

Actin filaments (microfilaments)

Question 17

Which of the following best describes the central dogma of molecular biology?

Accepted Answer

$DNA \rightarrow RNA \rightarrow Protein$

Question 18

A mutation in the gene encoding a membrane channel protein could most directly affect which cellular process?

Accepted Answer

Facilitated diffusion of ions

Question 19

Which organelle contains hydrolytic enzymes for digesting foreign material and cellular debris?

Accepted Answer

Lysosome

Question 20

Which process is most directly responsible for the secretion of insulin from pancreatic cells?

Accepted Answer

Exocytosis

Cell Structures and Their Functions: Study Notes

Study Guide - Practice Questions