Plasma Membrane & Cellular Transport - Honors

Select the statement that best decribes what happens during osmosis.

• Water molecules move from a low to high concentration

• Large solutes move from a high to low concentration

• Large solutes move from a low to high concentration

• Both water molecules and solutes move from a low to high concentration

• Water molecules move from a high to low concentration

Answer explanation

Osmosis is the movement of water molecules from an area of high concentration (more water, less solute) to an area of low concentration (less water, more solute) until equilibrium is reached. Thus, water moves from high to low concentration.

Why is it dangerous to drink salt water?

• It is hypertonic to cells

• It is hypotonic to cells

• It is isotonic to cells

• Only fish should drink salt water

Answer explanation

Drinking salt water is dangerous because it is hypertonic to cells, meaning it has a higher concentration of salt than the cells. This causes water to leave the cells, leading to dehydration and potential cell damage.

Diffusion of water through a semi-permeable membrane is called?

• Exocytosis

• Osmosis

• Facilitated Diffusion

• Endocytosis

• Protein pumping

Answer explanation

Osmosis is the process of water diffusion through a semi-permeable membrane, allowing water to move from an area of lower solute concentration to an area of higher solute concentration, thus maintaining balance.

Which way will the water molecules move during osmosis?

• Out of the cell, so the cell swells

• Out of the cell, so the cell shrinks

• Into the cell, so the cell shrinks.

• Into the cell, so the cell swells.

• The water molecules won't move.

Answer explanation

During osmosis, water moves out of the cell when the surrounding solution is hypertonic, causing the cell to lose water and shrink.

 If the water concentration and volume of a cell 

increase when it is placed 

in a solution, then the solution is

 said to be __________ to the 

cell.

•  hypertonic

• equal

•  isotonic

•  hypotonic 

Answer explanation

The solution is said to be hypotonic to the cell because an increase in water concentration and volume indicates that water is moving into the cell, which occurs when the external solution has a lower solute concentration than the cell.

Cellular transport that moves large or charged molecules across a membrane from an area of low concentration to an area of high concentration and requires ATP energy is:

• Osmosis

• Simple Diffusion

• Active Transport

• Passive Transport 

• Facilitated Diffusion

Answer explanation

Active transport is the process that moves large or charged molecules against their concentration gradient, from low to high concentration, using ATP energy. This distinguishes it from passive transport methods.

Cellular transport that moves molecules across a membrane from an area of high concentration to an area of low concentration and does not require ATP energy is:

• Active Transport 

• Endocytosis

• Osmosis

• Passive Transport 

• Exocytosis

Answer explanation

Passive transport moves molecules from high to low concentration without using ATP. This process includes diffusion and osmosis, making it the correct choice for the question.

Which method of passive transport is represented in the image?

• Protein ion pumps

• Simple Diffusion

• Osmosis

• Facilitated Diffusion

• Exocytosis

Answer explanation

Facilitated diffusion is a type of passive transport that uses protein channels to help move molecules across the cell membrane. This method is specifically for larger or polar molecules that cannot easily pass through the lipid bilayer.

In what method of cellular transport does the cell utilize vesicles to remove large molecules or bulk materials from the cell?

• Osmosis

• Exocytosis

• Protein ion pumps

• Endocytosis

• Facilitated diffusion

Answer explanation

Exocytosis is the method of cellular transport where vesicles fuse with the cell membrane to release large molecules or bulk materials outside the cell, making it the correct choice for this question.

In what method of cellular transport does the cell utilize vesicles to move large molecules or bulk materials into the cell?

• Osmosis

• Exocytosis

• Protein ion pumps

• Endocytosis

• Facilitated diffusion

Answer explanation

Endocytosis is the method of cellular transport where the cell uses vesicles to engulf large molecules or bulk materials, bringing them into the cell. This distinguishes it from other transport methods listed.