Vocabulary Part 1

• Solute – molecules being dissolved in a solution

• Solvent – substance doing the dissolving in the solution (usually water)

• Concentration – amount of solute per unit solvent

• Diffusion – Movement of molecules (solute) from an area of greater concentration to an area of lesser concentration.

• Concentration Gradient – the difference in concentrations across a space or a membrane

• Equilibrium – there is no NET movement of molecules across a space or membrane

Vocabulary Part 1

• Permeable – molecules can go through membrane

• Selectively Permeable (aka Semipermeable)— movement of molecules is selective based on size, polarity, and charge

• Impermeable – molecules cannot go through membrane

• Facilitated Diffusion — molecules move down the concentration gradient with the help of a protein in the cell membrane. No energy required.

• Active Transport -- molecule uses a protein in the cell membrane to move against the concentration gradient. Energy required.

Vocabulary Part 2• Osmosis – diffusion of water through a semipermeable membrane.

• Hypotonic – less concentrated

• Hypertonic – more concentrated

• Isotonic – equal concentrations

• Plasmolysis – when a cell collapses on itself because it lost too much water

• Cytolysis -- when a cell bursts because it has taken in too much water (more common in animal cells…why?)

Vocabulary Part 2

• Turgor Pressure – pressure in a plant cell due to water flowing in

• Contractile Vacuole – vacuoles that pump water out of a cell to keep a concentration gradient present.– Example: freshwater fish (is hypertonic to environment). Pumps

water out

• Water Potential – how much water a solution has. Water will always move from high water potential to low water potential

– High Water Potential – a lot of water in a solution, so it is very dilute

– Low Water Potential – not a lot of water in a solution, so it is very concentrated

Another Type of Active Transport

• way in which a cell takes in big molecules or gets rid of big molecules

• Requires energy (ATP)

• how some of our immune cells “eat” bacteria

• how some of our cells secrete packaged proteins made in the Rough ER

• Endocytosis (in)• Exocytosis (out)

Exocytosis