Biology

Solutions, Diffusion, Osmosis, Cell Membrane, Ion Channels, & Facilitated Diffusion

Solutions- when 2 substances are evenly distributed throughout each other

Solute- the part of the solution that's being dissolved (ex. salt)

Solvent- the part of the solution that dissolves something else (ex. H2O or water)

*Descriptions: polar mixes with polar, nonpolar mixes with nonpolar (like dissolves like)

-

Diffusion- movement of molecules from high to low concentration, only nonpolar and small molecules can diffuse across the membrane easily

Passive Transport- movement of molecules across the membrane not requiring energy

Concentration Gradients- a difference in an amount of space

Equilibrium- equal concentration (even distribution, balanced)

-

Osmosis- the diffusion of water-movement of H2O from high H2O to low H2O concentration

Hypertonic- a solution with more solute & less H2O than the inside of a cell, water moves out of cell and cell shrinks

Hypotonic- a solution with more H2O than the inside of a cell, water moves in the cell, and cell expands and sometimes explodes

Isotonic- a solution with equal amount of H2O and solute inside and outside a cell, water moves in and out of cell equally, cell stays normal and healthy

-

Cell Membrane Function- allow some things in & keep others out; provides a filter or barrier; made up of...

Phospholipid Bilayer- 2 layers of lipid/nonpolar membrane with polar edges

Proteins- stuck in membrane like a tunnel, transport things

Receptors- on surface to recognize/identify outside molecules

*Description: selectively permeable (allows some things to pass through the membrane but keeps out others)

-

Ion Channels- a transport protein with a polar pore through which ions can pass: only lets certain things through: if ions are positive, they'll diffuse inside, if negative diffuse outside

*Descriptions: from high to low concentration if passive, but if it uses energy it could move in opposite directions

-

Facilitated Diffusion- movement of molecules from high to low concentration with the help of a protein (does not require energy)

Carrier Protein- bind a specific substance on one side of the cell membrane, carry the substance across the cell membrane, and release it on the other side