AP Bio Unit 2

Water Potential

Water Potential

INdicates the potential energy of water in a system, helping predict the direction of water movement (Formula: Ψ=Ψs +Ψp)

Solute Potential

The effect of solute concentration on water potential

Pressure Potential

Physical pressure on a solution (equals zero if open to the air)

Hypertonic

HIgher solute concentration outside the cell, leading to water moving out and cell shrinking

Hypotonic

Lower solute concentration outside the cell, causing water to move in, and cells may swell or burst

Isotonic

Equal solute concentrations on both sides, so water moves equally in both directions, maintaing cell shape

Passive Transport

Movement without energy (ATP), driven be concentration gradient. HIGH TO LOW

Active Transport

Movement with energy (ATP) against their concentration gradient, LOW TO HIGH

Equlibrium

The concentration of solutes is equal across a membrane, so there’s no net movement of particles, though molecules may still move across randomly

Diffusion

The movement of molecules from an area of high concentration to an area of low concentration, not limited to water HIGH TO LOW

Ideal Cell Size

smaller cells have a higher surface area-to-volume ratio, allowing efficeitn diffusion of nutrients and waste

Osmolarity

A measure of solute concentration in a solution; high osmolarity indicates high solute concentration and affects water potential

Nucleus

Stores DNA and coordinates cell activites

Mitochondria

Produces ATP through cellular respiration

Chloroplasts

plants only, conducts photosynthesis

Ribosomes

synthesises proteins

Rough ER

modifies proteins, has ribosomes

Smooth ER

synthesizes lipids, no ribosomes

Golgi Apparatus

Processes, packages, and ships proteins and lipids

Lysosomes

Contains enzymes for digestion

Vacuoles

Stores nutrients and waste; large central vacuole in plant cells helps maintain turgor pressure

Prokaryotes

No nucleus, smaller, no membrane-bound organelles (ex: bacteria)

Eukaryotes

Has nucleus, larger, complex with membrane-bound organelles (ex: plants, animals)

Prokaryotes & Eukaryotes

Have DNA, ribosomes, plasma membrane, and cytoplasm

ATP in Active Transport

Provides energy needed to move substances against their concentration gradient (ex: the sodium-potassium pump)

Structure of Cell/Plasma Membrane

Phospholipid bilayer with embedded proteins, cholesterol, and carbohydrate chains

Function of Cell/Plasma Membrane

Regulates what enters and leaves the cell, provides structural support, and facilitates communication between cells

Substances That Can Pass Freely Through the Plasma Membrane

small, nonpolar molecules like oxygen, carbon dioxide, and some lipids

Substances That Can NOT Pass Freely Through the Plasma Membrane

large molecules, ions, and polar molecules, usally require trasnport proteins