Transcript 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).