| Term | Definition |
|---|
| Cell membranes have 2 thin phosphlipid layers that are | fluid with embedded proteins. |
| Sugars attached to the lipids & the proteins form the | surface of the cell and are unique for recognition purposes. |
| Many chemical reactions can dissolve (soluble) directly into the | water surrounding the cell. |
| Many ions and other substances necessary for life processes need to | get in the cell. |
| The function of the membrane is to regulate what is | permitted entry/exit. |
| Semi permeable helps to | maintain homeostasis balance. |
| Small molecules permeate | freely. |
| Ex. of small molecules permeating freely | water and alcohol |
| Materials are transported | with or without energy; depending on the concentration. |
| Osmosis – diffusion | movement of water form high to low |
| Low osmotic pressure | low solute = hypotonic |
| High osmotic pressure | high solute = hypertonic |
| Isotonic | equal amt. of solute on both sides |
| Hypotonic | too much water and can lyse |
| Hypertonic | too little water and can shrivel (crenation) |
| Passive transport | no energy needed |
| Diffusion | movement of molecules from an area of greater to lesser concentration until they’re equal. |
| Ex. of Diffusion | CO2; O2; food. |
| Facilitated Diffusion | passive transport that needs a carrier protein. |
| Concentration gradient | amount of difference in concentration |
| Osmosis | diffusion of H2O from high to low concentration |
| 3 Types of Concentration | isotonic; hypotonic; hypertonic |
| Isotonic Concentration | equal amounts of solute + water in and out of the membrane. |
| Hypotonic Concentration | low amount of solute + high amounts of water outside the cell-water moves in; turgid |
| Hypertonic Concentration | high amount of solute + low amount of water outside the cell-water moves out; cell shrinks; in plants this is plasmolysis (wilting). |
| Both passive transports continue until they are | evenly distributed |
| Active Transport | energy (ATP) needed to move against concentration gradient. |
| Transport proteins can bind to | charged particles (ions) or large uncharged polar molecules (glucose nucleotides) |
| Transport proteins can | ”carry” charged/uncharged particles across membranes. |
| Transport proteins are a.k.a. | carrier proteins. |
| Membranes may fold in and | close over molecules that its taking in – phagocytosis |
| Phagocytosis uses | psuedspods – WBC |
| Endocytosis | molecules move in |
| Exocytosis | molecules move out |
| Gases exchanged by diffusion in unicellular organisms is | diffused directly into the water. |
| Multicellular organisms require: | specialized structures with lg. surface area. |
| Ex. of Multicellular Organisms | gills in fish; lungs in animals; spiracles in insects; stomates in plants. |
| Humans air travels from | nose-pharynx-tracheae-bronch-alveoli (60m2)-lungs |
| Plants guard cells on each side of the stomates well with | water and open to allow CO2 in and H2O + O2 out. |
| In drought or dark the guard cells | close the stomata (minimizing transpiration-loss of water.) |
| Waste excretion also needs special structures | contractile vacuoles in unicellular organisms; kidneys in animals. |
| Humans; blood plasma filtered by nephrons in kidneys after reabsorption of | Na; K; and water-ureter-urinary bladder-urethra out of the body |
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