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16 Cards in this Set
- Front
- Back
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Diffusion across phospholipid bilayer |
Hydrophobic barrier is impermeable to polar molecules as the hydrophobic inner core repel against substances with positive or negative charge Permeable to hydrophobic molecules and oxygen, carbon dioxide, lipid soluble molecules |
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Artificial membrane contain |
Visking, dialysis tubing |
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Factors affecting diffusion |
Temperature Concentration gradient Surface area to volume ratio Distance Thickness of membrane |
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Facilitated diffusion |
Polar molecules and ions pass through membranes via channel protein Selectively permeable - specific to one molecules |
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Active transport process |
Ion binds to carrier protein on outside of cell ATP binds to carrier protein inside of cell and is hydrolysed to ADP and phosphate The binding of phosphate to carrier protein cause protein to change shape and opening up to inside of cell Ion released into cell phosphate molecule is release and recombine with ADP Carrier protein returns to original shape |
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Bulk transport is for Types of bulk transport |
Large molecules such as hormones, enzymes and bacteria Endocytosis Phagocytosis- for solid Pinocytosis - for liquid |
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Process of endocytosis and exocytosis |
Contact with large molecule causes an invagination in plasma membrane Plasma membrane fuses around large molecule and trapped it into vesicle Vesicle pinches off and moves into cytoplasm Vesicle fuses with lytic enzymes releases by lysosomes and break material into small soluble molecule Exocytosis - vesicle fuses with plasma membrane and contents is secreted out of cell |
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Water potential |
Pressure exerted by water molecules colliding with membrane / container |
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Water potential of pure water |
0 kPa |
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More concentrated solution is , the what the water potential |
More negative |
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Diffusion of water to closed system result in |
Increase volume and increase pressure - hydrostatic pressure |
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Animal cell placed in solution with higher water potential than cytoplasm |
Water diffuse into cytoplasm by osmosis Hydrostatic pressure inside cell increases Thin plasma membrane cannot stretch and withstand pressure Cell swell and burst , cytolysis |
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Animal cell placed in solution with lower water potential than cytoplasm
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Water diffuse out by osmosis Reduction in volume of cell Plasma membrane pucker , crenation |
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Isotonic |
Cell surrounded by aqueous solution with equal water potential Movement of water into cell is equal to movement of water out of cell |
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When water diffuses in by osmosis to plant cells |
Volume of cytoplasm and vacuole increases Hydrostatic pressure pushes plasma membrane against rigid cell walls Turgor pressure increases Resist entry of further water, protoplast swells and become turgid |
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When water diffuses out by osmosis to plant cells |
Reduction of volume of cytoplasm and vacuole Pulls plasma membrane from cell walls Protoplast shrinks and become plasmolyse |
