Diffusion and Osmosis

Question 1

What is diffusion?

Answer 1

The spontaneous movement of molecules,atoms or ions from an area of higher concentration to an area of lower concentration of molecules,atoms or ions until dynamic equilibrium is achieved.

Question 2

What is osmosis?

Answer 2

Osmosis is the spontaneous movement of water molecules from a region of higher water concentration to a region of lower water concentration, down their water concentration gradient, across a differentially permeable membrane, until equilibrium is reached.

Question 3

Osmosis is the way many living things ____ ___ water.

Answer 3

Take up

Question 4

How do water get into plants?

Answer 4

By osmosis

Question 5

Explain the process of how water moves into plant cells by osmosis:

Answer 5

• The cell membrane of the plant acts a partially permeable membrane.
• The cell sap inside the vacuole is a strong solution.
• Water passes into the plant cell by osmosis.
• The concentration of the sap in the vacuole is now weaker.
• Water passes from the weak solution into the strong solution in the next cell by osmosis.

Question 6

Name the 6 factors that affect diffusion:

Answer 6

• Concentration gradient
• The surface area to volume ratio
• The size of the particles
• The distance over which the movement occurs
• The temperature
• The pressure acting on the system.

Question 7

What is active transport?

Answer 7

Movement of ions or molecules through the cell membrane, from a region low concentration to a region of high concentration against a concentration gradient; using energy released during respiration.

Question 8

What form is the energy in active transport? And what does it allow?

Answer 8

ATP - and carrier proteins carry the molecules

Organic molecules that are too large to pass through the membrane easily

Question 9

What is facilitated diffusion?

Answer 9

The passive movement of molecules and particles down the concentration gradient through the channel protein.

Question 10

Role of cholesterol in cell surface membrane of an animal cell

Answer 10

Maintains fluidity of the membrane/prevents soluble substances from leaking through the membrane

Question 11

Role of carrier proteins

Answer 11

Transport molecules against a gradient via active transport

Question 12

Role of glycoproteins

Answer 12

Receptor molecules