B3 - movement in and out of the cell

Question 1

What is the function of the cell membrane?

Answer 1

To control the movement of substances in and out of the cell.

Question 2

What is the structure of the cell membrane?

Answer 2

A phospholipid bilayer with embedded proteins.

Question 3

What are the two main types of cellular transport?

Answer 3

Passive transport and active transport.

Question 4

What is passive transport?

Answer 4

Movement of substances without energy input.

Question 5

What is active transport?

Answer 5

Movement of substances using energy (ATP), against a concentration gradient.

Question 6

What is diffusion?

Answer 6

Movement of molecules from an area of high concentration to low concentration.

Question 7

Is diffusion passive or active?

Answer 7

Passive – it does not require energy.

Question 8

What is simple diffusion?

Answer 8

Direct movement of small, nonpolar molecules through the phospholipid bilayer.

Question 9

Give examples of molecules that use simple diffusion.

Answer 9

Oxygen (O₂) and carbon dioxide (CO₂).

Question 10

What is facilitated diffusion?

Answer 10

Diffusion using protein channels or carriers for large or polar molecules.

Question 11

Give examples of molecules that use facilitated diffusion.

Answer 11

Glucose and amino acids.

Question 12

What factors affect the rate of diffusion?

Answer 12

Concentration gradient, temperature, particle size, and distance.

Question 13

What is osmosis?

Answer 13

The diffusion of water across a selectively permeable membrane.

Question 14

What drives osmosis?

Answer 14

Differences in solute concentration.

Question 15

Does osmosis require energy?

Answer 15

No – it is a passive process.

Question 16

Define isotonic solution.

Answer 16

A solution with equal solute concentration as the cell.

Question 17

Define hypotonic solution.

Answer 17

A solution with lower solute concentration than the cell.

Question 18

Define hypertonic solution.

Answer 18

A solution with higher solute concentration than the cell.

Question 19

What happens to an animal cell in a hypotonic solution?

Answer 19

It swells and may burst.

Question 20

What happens to a plant cell in a hypotonic solution?

Answer 20

It becomes turgid.

Question 21

What happens to an animal cell in a hypertonic solution?

Answer 21

It shrinks (crenates).

Question 22

What happens to a plant cell in a hypertonic solution?

Answer 22

It becomes plasmolyzed.

Question 23

What is turgor pressure?

Answer 23

The pressure of the cell contents against the cell wall in plant cells.

Question 24

What is the role of osmosis in plants?

Answer 24

It helps absorb water and maintain cell shape.

Question 25

Give two practical uses of osmosis.

Answer 25

Food preservation (salting) and water purification (reverse osmosis).

Question 26

What is active transport?

Answer 26

Movement of substances against a concentration gradient using ATP.

Question 27

What type of proteins does active transport use?

Answer 27

Specific transport proteins.

Question 28

What is primary active transport?

Answer 28

Direct use of ATP to move substances, e.g., sodium-potassium pump.

Question 29

Give three examples where active transport is important.

Answer 29

Nutrient absorption in intestines, root hair absorption in plants, and ion balance in cells.

Question 30

What is the difference between passive and active transport?

Answer 30

Passive does not use energy; active requires energy.

Question 31

What is the role of facilitated diffusion?

Answer 31

To allow large or polar molecules to cross membranes using proteins, without energy.

Question 32

What are some medical applications of diffusion and osmosis?

Answer 32

Dialysis and drug delivery systems.

Question 33

Name a disorder related to transport mechanisms.

Answer 33

Cystic fibrosis – caused by impaired chloride ion channels.

Question 34

How does diabetes insipidus relate to cellular transport?

Answer 34

It disrupts water reabsorption in the kidneys.

Question 35

How do halophytes adapt to their environment?

Answer 35

They are adapted to survive in high salt concentrations.

Question 36

How do desert animals conserve water?

Answer 36

They have specialized kidney functions to minimize water loss.