1. The student is expected to: 4B investigate and explain cellular processes, including homeostasis, energy conversions, transport of molecules, and synthesis of new molecules and 9A compare the structures and functions of different types of biomolecules, including carbohydrates, lipids, proteins, and nucleic acid

2. KEY CONCEPT Materials move across membranes because of concentration differences.

3. Diffusion and osmosis are types of passive transport.
Passive transport does not require energy input from a cell.
Molecules can move across the cell membrane through passive transport.
There are two types of passive transport.
diffusion
osmosis

4. Diffusion and osmosis are types of passive transport.
Diffusion is when molecules move down a concentration gradient.
Movement is from a region of higher concentration to a region of lower concentration.

5. Diffusion and osmosis are types of transport.
Osmosis is the diffusion of water molecules across a semipermeable membrane.

6. Diffusion and osmosis are types of transport.
There are three types of solutions.
isotonic
hypertonic
hypotonic

7. Some molecules can only diffuse through transport proteins.
Some molecules cannot easily diffuse across the cell membrane.
Facilitated diffusion is diffusion through transport proteins.