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Cell Transport. Cell Membrane. The cell membrane controls what can go into and out of the cell. It looks like this up close. . Permeable . Means something is able to pass through. Like water through a paper towel.
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Cell Membrane • The cell membrane controls what can go into and out of the cell. It looks like this up close.
Permeable • Means something is able to pass through. • Like water through a paper towel. • Because water can pass through the paper towel, it is said to be PERMEABLE to water.
Selectively Permeable • The ability to choose or select what can pass through. • The paper towel is permeable to water but not to sand. The paper towel is selectively permeable.
Selectively Permeable Cell Membrane • The cell membrane is selectively permeable just like the paper towel. • The cell membrane can choose what can and can’t go in or out of the cell based on the size of the particle. • If the particle is too big, it can’t enter the small holes in the cell membrane.
Diffusion • Some substances pass through the cell membrane easily and require no energy • This is called diffusion. • An example of diffusion is food coloring and water.
Three Forms of Transport Across the Membrane Example: Oxygen or water diffusing into a cell and carbon dioxide diffusing out. Osmosis – diffusion of water across a selectively permeable membrane from an area of a high concentration of water to an area of a low concentration of water
Three Forms of Transport Across the Membrane Examples: Glucose or amino acids moving from blood into a cell.
Three Forms of Transport Across the Membrane Examples: Pumping Na+ (sodium ions) out and K+ (potassium ions) in against strong concentration gradients.
Equilibrium • Occurs when molecules of one substance is spread evenly through out another substance; maintain a balance. water Color molecule
HOMEOSTASIS • The ability or tendency of an organism or cell to maintain internal equilibrium. K+ Na- Na- K+ K+ K+ Cell K+ K+ Na- Na- K+ Na- K+ K+ Na- Na- K+ K+ K+ Na-