Download Cell

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
Nucleus
Membrane-enclosed structure
that contains a cell’s DNA
Eukaryote
Larger, more complex cell
that contains a nucleus (animal, plant, fungi, protist)
Prokaryote
Small, simple cell that
does not contain a nucleus
(bacteria)
Unicellular
A few
eukaryotes are
unicellular
All prokaryotes
are unicellular
Organism made from just one cell
Multicellular
Organism made from many cells that are specialized
Animal Cells
Multicellular, eukaryotic, specialized. Obtain glucose from
other organisms; no cell walls.
Plant Cells
Multicellular, eukaryotic, specialized. Make their own glucose;
have chloroplasts and cell walls.
Fungal Cells
Multicellular, eukaryotic, specialized; obtain glucose from
other organisms; have cell walls.
Protist Cells
Eukaryotic; may be multicellular or unicellular. Have cells
walls. No specialization. Some “eat”, others make their own
glucose.
Bacteria Cells
Unicellular, prokaryotic. No specialization. Have cell wall.
Some “eat”, others make their own glucose.
Cell Membrane
Cell membrane
Copyright Pearson Prentice Hall
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 Wall
Cell membrane
Supporting layer around some CMs. Has pores; allows solute
particles to reach the CM, but does not regulate them
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
Less
concentrated
More
concentrated
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
Plasma
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
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
Plasma
Plasma
Two layers (bi = two)
Diffusion
Permeable
membrane
= water
molecule
= solute
molecule
Side A
More Solute
Side B
Less Solute
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.
Osmosis
Selectively
Permeable
membrane
= water
molecule
= solute
molecule
Side A
Less Water
Side B
More water
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.
Isotonic
= water
molecule
= solute
molecule
Concentration of solute inside and outside cell are equal.
Water moves in both directions; cell does not change shape.
Hypertonic Solution
= water
molecule
= solute
molecule
Concentration outside cell is higher than inside cell. Water
moves out of the cell; cell shrinks. Ex: goldfish in sea water.
Hypotonic Solution
= water
molecule
= solute
molecule
Concentration inside cell is higher than outside cell. Water
moves into the cell; cell expands. Ex: shark in fresh water.
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).