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Unit 2 Homeostasis
Unit 2 Cell Transport & Homeostasis
Term | Definition |
---|---|
Cell Membrane | maintains homeostasis with the movement of water and the transport of molecules through selective permeability |
Cell Membrane | functions: maintain homeostasis, recognize other cells, facilitates and controls substances entering and exiting the cell, holds cytoplasm in place, |
Homeostasis | the ability of an organism or cell to maintain an internal balance |
Diffusion | Movement of molecules from an area of high concentration to low concentration; molecules move down a concentration gradient |
Osmosis | Diffusion of water from an area of high concentration to low concentration; water molecules move down a concentration gradient |
Concentration Gradient | the difference in the number of molecules on either side of a cell membrane |
Active Transport | Movement of particles across a cell membrane from a region of LOW concentration to a region of HIGH concentration using proteins as pumps; molecules move UP a concentration gradient; REQUIRES ENERGY |
Passive Transport | Movement of particles across a cell membrane from a region of HIGH concentration to a region of LOW concentration ; molecules move DOWN a concentration gradient; NO energy required |
Examples of Maintaining Homeostasis | Guard cells around the stomata of a plant cell controlling water loss ; Aquatic organisms pumping water out of their cells; animal shivering while cold to generate movement for heat; people sweating when hot to cool the body; low oxygen levels causes an increase in respiration rate |
Lipids | Biomolecule - Fat and waxy substances which repel water and does not breakdown in water; insulates the body to maintain internal temperature ; example - phospholipid bilayer of the cell membrane; blubber found on a whale |
Proteins | Biomolecule - embedded in the cell membrane to move large molecules and ions into and out of the cell |
Facilitated Diffusion | Movement of materials from an area high concentration to low concentration through a protein channel |
Selective Permeability | Movement of some molecules across the cell membrane while other molecules are not allowed to pass through |
Nucleic Acids | Biomolecule - Stores genetic material |
Lipids | Biomolecule - Fats & oils which serve as long-term energy storage |
Carbohydrates | Biomolecule - Sugar & Starches which serve as primary sources of energy |
Proteins | Biomolecule - provides structure for organisms and speed up the rate of chemical reactions by moving ions & large molecules across the cell membrane |
Phospholipids | make up the cell membrane with hydrophilic heads and hydrophobic tails which form a double layer and act as a selectively permeable membrane |