Unit 3-cell membrane

Polarity

The separation of electric charge in a molecule or bond, creating regions with partial negative (δ−δ−) and partial positive (δ+δ+) charges.

Hydrogen Bonds

A weak attraction between a partially positive hydrogen atom and an electronegative atom like oxygen, nitrogen, or fluorine.

Cohesion

The attraction between molecules of the same substance, causing them to stick to one another.

Adhesion

The attraction between molecules of different substances, causing them to stick to other surfaces.

Heat Capacity 

The amount of heat energy required to raise the temperature of a substance by one degree Celsius.

Mixture

A combination of two or more substances that are physically mixed together but not chemically combined.

Solution

a homogeneous mixture composed of two or more substances distributed evenly on a molecular or ionic level

Solute

The minor component in a solution, dissolved in the solvent.

Solvent

a substance—usually a liquid—that dissolves another substance, known as a solute, to form a uniform mixture called a solution

Suspension

a heterogeneous mixture (a mixture that is not the same all the way through) where solid or liquid particles are spread through a liquid or gas, but do not dissolve

pH (Acid, Base, Buffer)

An acid-base buffer solution resists changes in pH when small amounts of a strong acid or a strong base are added

Ion

An atom or molecule with a net electric charge due to the loss or gain of one or more electrons.

Phospholipid Bilayer

a double layer of lipid molecules that forms the fundamental, protective barrier around all living cells and their internal organelles

Hydrophobic

Tending to repel or fail to mix with water.

Hydrophillic

"water-loving" or having a strong affinity to interact with, absorb, or dissolve in water

Fluid Mosaic Model

explains the structure and function of cell membranes as a flexible lipid bilayer with a shifting pattern of embedded proteins, cholesterol, and carbohydrates

Selectively Permeable

Lets things in and out of the cell. a barrier that allows certain molecules and ions to pass through while blocking others

Diffusion 

the net movement of particles from an area of high concentration to an area of low concentration driven by random molecular motion

Facilitated Diffusion

the passive movement of molecules or ions across a cell membrane down their concentration gradient with the help of specialized transport proteins

Osmosis

A process by which molecules of a solvent tend to pass through a semipermeable membrane from a less concentrated solution into a more concentrated one, thus equalizing the concentrations on each side of the membrane.

Passive Transport

the movement of molecules across a cell membrane from an area of high concentration to an area of low concentration without using cellular energy

Active Transport

the movement of molecules or ions across a cell membrane from a region of lower concentration to a region of higher concentration, going against the concentration gradient using cellular energy

Equilibrium

A state in which opposing forces or influences are balanced.

Concentration Gradient

the difference in the concentration of a substance between two connected areas, such as across a cell membrane

Osmotic Pressure

the minimum pressure that must be applied to a solution to stop the net flow of its pure solvent across a semipermeable membrane

Hypertonic Solution

a liquid with a higher concentration of solutes (such as salt or sugar) than the fluid or cells found inside it

Hypotonic Solution

a liquid with a lower concentration of solutes (dissolved particles) than the fluid or cells found inside it, which causes water to flow into the cells through osmosis

Isotonic Solution

a fluid with the same concentration of solutes as another fluid or body cell, resulting in no net movement of water across the cell membraneExocytosis

Exocytosis

A process by which the contents of a cell vacuole are released to the exterior through fusion of the vacuole membrane with the cell membrane.

Endocytsosis

an active transport process where a cell brings in substances from the outside by folding its cell membrane inward to form a small sac called a vesicle

Surface Area to Volume Ratio

compares the outer surface area of an object to its internal volume