AP Biology Vocab Chapters 5 and 6

Peripheral proteins

proteins loosely attached to the surface of the membrane

Integral proteins

proteins that penetrate the hydrophobic core

Diffusion

process of random movement toward a state of equilibrium

Concentration gradient

a difference in concentration across a space

Concentration

amount of solute relative to amount of solvent

Equilibrium

condition in which the concentration of a substance is equal throughout

Passive transport

movement of molecules across a cell membrane from an area of high concentration to lower concentration, and does not require energy

Simple diffusion

random movement of molecules through the lipid bilayer of a membrane

Osmosis

special kind of diffusion that involves movement of H2O through membrane

Hypertonic

an adjective describing a solution that has a higher solute concentration than another solution

Hypotonic

an adjective describing a solution that has a lower solute concentration than another solution

Isotonic

adjective describing a solution that has an equal solute concentration as another solution

Facilitated diffusion by channel proteins

molecules diffuse across the cell membrane with assistance from membrane proteins

Coupled Transport

the moving of more than one molecule at a time

Symport

moves 2 molecules in the same direction

Antiport

moves 2 molecules in opposite direction

Active transport

transport of materials across the cell membrane up the concentration gradient, and requires input of energy from the cell

Sodium potassium pump

carrier protein that uses ATP to actively transport Na+ out of the cell and K+ into the cell

Endocytosis

process by which material is brought into a cell by invagination of the plasma membrane and formation of a vesicle

Bulk Transport

moving large quantities of materials in or out of the cell

Phagocytosis

"cell eating" type of endocytosis in which large particles taken in by the cell

Pinocytosis

"cell drinking" type of endocytosis in which liquids or small particles are taken in by the cell

Receptor mediated endocytosis

type of pinocytosis that's very specific/ efficient, specific molecules can be brought into the cell, determined by cell receptors

Desmosome

a strong cell to cell junction that attaches adjacent cells to one another

Tight junction

leak proof junctions that create tight seals between cells

Gap junction

forms channels between adjacent cells/ allow communication between cells with the exchange of materials

Energy

the capacity to do work

chemical energy

energy stored in organic molecules

First law of thermodynamics (law of conservation of energy)

energy can't be created or destroyed, but can be transformed from one form to another

Second law of thermodynamics

energy can't be changed from 1 form to another w/out loss of usable energy

Entropy

relative amount of disorganization

free energy(g)

how much energy is available to do work

ΔG

change in free energy

endergonic

reaction where the change in free energy is positive

exergonic

reaction where the change in free energy is negative

coupled transport

the moving of more than one molecule at a time an across the membrane

uniport

a mechanism of transport across a membrane in which only one molecule at a time passes across the membrane

cell membrane

surrounds both cell and organelles and is composed of a phospholipid bilayer with embedded proteins

fluid mosaic model

developed in 1972 to explain the structure of cell membranes