Cell

The smallest unit of life that is still classified as “alive”

Organelle

Parts of the cell that play a role in the production of protein

Membrane-enclosed structure that contains a cell’s DNA

Nucleus

Larger, more complex cellthat contains a nucleus (animal, plant, fungi, protist)

Eukaryote

Small, simple cell that does not contain a nucleus

(bacteria)

Prokaryote

Organism made from just one cell

Unicellular

All prokaryotesare unicellular

A few eukaryotes are

unicellular

Organism made from many cells that are specialized

Multicellular

Multicellular, eukaryotic, specialized. Obtain glucose from other organisms; no cell walls.

Animal Cells

Multicellular, eukaryotic, specialized. Make their own glucose; have chloroplasts and cell walls.

Plant Cells

Multicellular, eukaryotic, specialized; obtain glucose from other organisms; have cell walls.

Fungal Cells

Eukaryotic; may be multicellular or unicellular. Have cells walls. No specialization. Some “eat”, others make their own

glucose.

Protist Cells

Unicellular, prokaryotic. No specialization. Have cell wall. Some “eat”, others make their own glucose.

Bacteria Cells

Regulates the exchange of solute particles between the cell and its liquid environment. Electrically neutral (no charge). Permeable to water and small molecules; impermeable to

large/charged molecules.

Cell Membrane

Copyright Pearson Prentice Hall

Cell membrane

Supporting layer around some CMs. Has pores; allows solute particles to reach the CM, but does not regulate them

Cell Wall

Cell membrane

Solute

A substance that can dissolve in water(Ex: salt, glucose, O2, CO2). Some solute particles are charged (Na+, Cl-)

Solution

A mixture of water and dissolved solute(Ex: plasma)

Concentration

The amount of solute dissolved in a liquid. Mass/volume. Concentration of solute inside and outside a cell are different.

Ex: CO2 more concentrated outside a cell; salt more concentrated outside the cells of marine animals

Less concentrated

More concentrated

Fluid portion of the blood; a solution of water + dissolved solute; located on both sides of the CM; CM’s are in constant

contact with it

Plasma

Ion

Particles of solute that have an electric charge (Ex: K-, Na+). Cannot pass directly through the neutral CM; must go

through protein gates/pumps

Bilayer

Two layers (bi = two)

Plasma

Plasma

Diffusion

The movement of solute molecules from an area of high concentration to an area of low concentration. Does not

require energy. Uses a permeable membrane.

Permeable membrane

Side A More Solute

Side B Less Solute

= water molecule

= solute molecule

Osmosis

The diffusion of water molecules. Also moves from H -> L; does not require energy. Uses a selectively permeable

membrane. Water always moves to area with more solute.

Selectively Permeable membrane

Side A Less Water

Side B More water

= water molecule

= solute molecule

Isotonic

Concentration of solute inside and outside cell are equal. Water moves in both directions; cell does not change shape.

= water molecule

= solute molecule

Hypertonic Solution

Concentration outside cell is higher than inside cell. Water moves out of the cell; cell shrinks. Ex: goldfish in sea water.

= water molecule

= solute molecule

Hypotonic Solution

Concentration inside cell is higher than outside cell. Water moves into the cell; cell expands. Ex: shark in fresh water.

= water molecule

= solute molecule

Facilitated Diffusion

Diffusion of large/charged molecules through protein channels embedded in the CM. Still H -> L; does not require

energy.

Active Transport

“Pumping” molecules against diffusion. Moves L -> H; requires energy (to change shape of protein). Ex: “pumping”

CO2 out of cell; endocytosis, exocytosis

Endocytosis

A form of active transport; taking a substance into the cell. Requires energy (cell changes shape). Phagocytosis: food;

pinocytosis: liquid.

Exocytosis

A form of active transport; pushing waste out of cell. Requires energy (cell changes shape).