cell theory cells are basic unit of life cells are produced from other cells cells maintain...
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Cell Theory
Cells are basic unit of life
Cells are produced from other cells
Cells maintain homeostasis
Homeostasis of tissues, and higher results from the coordinated effort of many cells
The cell membrane/plasma membrane
Physical isolation
Regulates exchange
Sensitivity
Structural Support
Membrane Structure
Phospholipid bilayer Hydrophillic heads at the membrane surface Hydrophobic tails on the inside
Membrane Proteins
Receptor proteins- recognize certain molecules Ex. Glucose can be recognized, and stimulates
absorption of glucose
Carrier Proteins- transport solutes across the membrane
Channels- allows water and small soluted through the membrane
Membrane Permeability
Detemines which substances can enter and exit the cell
Selective permeability- permits free passage of some materials, and restricts others
Passive passage- requires no energy
Active passage- requires energy
Transport processes
Diffusion- movement of molecules from a high concentration to a low concentration Osmosis- refers to the movement of water
specifically
Isotonic- no flow of water into or out of the cellHypotonic- water flows into cellHypertonic- water flows out of cell
Filtration
Hydrostatic pressure forces water and solute molecules through the membrane Ex. In capillaries this pressure pushed water
and nutrients into the tissues of your body
Carrier Mediated Transport
Proteins carry substance across the cell membrane
Facilitated diffusion- Insoluble nutrients like glucose are transported by passively proteins
Facilitated Diffusion
Active Transport
Ions or molecules are moved across the membrane using ATP
Ion pumps- protein that transport ions through the membrane Ex. K+, Na+, etc.
Vesicular Transport
Materials move into or out of the cell through vesicles (small sacs)
Endocytosis- packaging of material outside of the cell and then dumping them into the cell
Vesicle Transport (cont.)
Pinocytosis- “cell drinking” sac fills with extracellular fluid, depression forms in membrane, and gets deeper until it pinches off
Phagocytosis- “cell eating” membrane surrounds solid objects outside of the cell and pinches off inside of the cell
Exocytosis
Vesicle created inside the cell fused with the membrane, and discharges its contents outside the cell
Opposite process of endocytosis