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Bio Exam 1 2

Bio Exam 1 2 - Factors affecting membrance permeability...

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Factors affecting membrance permeability Bond struction and hydrocarbon chain length change membrane huidity and permeability Liqid bilayer with no unstructured fatty acids have higher permeability, more fluid Bilayers made of liquids with long, striaght, saturated fatty -acids tails are much less permeatable then membranes made of liqids with short, kinked, unstructured fatty-acid tails Cholesteral reduced membrane permeability The membranes permeability, decreases as temperature decreases Active transport(Steps of Na+/K- pump) The sodium- Potassium Pump Step 1: when Na+/K- ATPase is in the conformation shown here, binding sites with a high affinity for sodium ions are available Step 2: The sodium ions from the inside of the cell bind to these sites Step 3: Shape change: A phosphate group from ATP binds to the protein ln response, the protein changes shape Step 4: Release: The sodium ions leave the protein and move to the exterior of the cell Step 5: Unbound Protein: In this confirmation, the protein has binding aites with high affinity for pottassium ions Step 6: Potassium binding: Two potassium ions bind to the pump Step 7: Shape change: The phosphate group drops off the protein. In response the protein changes back to its original shape Step 8: Release: The potassium ions leave the protein and diffuse to the interior of the cell. These 8 steps repeat Four Major Roles of Organelles Biomolecules synthesis and transport - endomembrane system Food break down, storage, and trash removal -Peroxisomes, lysosomes, and vacueles Energy productuin
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-Mitochondria and chloroplasts Structural support and Movement -Cytoskeleton and cell walls Major Cytoskeleton Elements and Roles Actin Filaments (micro filaments) - maintain cell stape by resisting tensien (pull) - move cells via muscle contrction On cell crawling - divide animal cells in two -move organelles and cytoplasm in plants, fungi, and animals Intermediate filaments -maintain cell shape by resisting tension(pull) -ancher nucleus and some ther organelles Micro tubules Maintain cell shape by resisting compression(push)
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Bio Exam 1 2 - Factors affecting membrance permeability...

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