BIO1201 Test 2-1

BIO1201 Test 2-1 - Flagella & Cilia Same structural...

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Same structural design 9+2 Structure- only in eukaryotic cells (absent in higher plants) Flagella are larger and fewer in number Other elements involved in movement: Sliding filaments Molecular motors -proteins -use ATP Centrioles -in animals -similar to the base of the flagella & cilia
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The problem is the interior of the cell is different than its environment, so how do you defend the internal environment but still communicate with the external? -Transport materials across the barrier Biological membranes are made of proteins and phospholipids . An optimal intermediate “fluidity” -not too solid, not too fluid -preserves membrane function Membrane fluidity can acclimate Membrane fluidity can by adjusted by changed the ratio of saturated vs. unsaturated fatty acids Increased saturated fats increased the fluidity of the membrane At cold temperatures unsaturated fats would increase Transport Processes Active - against the concentration gradient -requires supplied energy ( ATP) -carrier molecule involved Passive - down the concentration gradient
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- does not require supplies energy - diffusion (simple(does not have a carrier molecule) or facilitated) Diffusion -net movement of molecules down a concentration gradient (Area of high concentration to low) If the concentration is equal there is still movement. Osmosis - the diffusion of water (high to low) Problems confronting organisms What if the concentration of solutes differs between the intracellular compartment and the environment? Hyper tonic -lower water potential - more solutes dissolved in it - tend to gain water Hypotonic -higher water potential - fewer solutes dissolved -tend to lose water Isotonic -equivalent water potentials - equal number of solutes dissolved - no net movement of water Marine Invertebrates Isotonic with seawater Accumulate free amino acids to match the tonicity of the seawater
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Marine Elasmobranch Fishes Isotonic with seawater Accumulate up to .5M urea Freshwater Bony Fishes Hypertonic to freshwater Gain water Marine Bony Fishes Hypotonic to seawater How do cells regulate metabolism?
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How do cells organize and control the chemical reactions that occur? Metabolic Transformations Chemical reactions Small steps Controlled processes Each step is controlled by a protein catalyst (enzyme) Biological Chemical Reactions -Regulated by protein catalysts -Synthesis of energy carrier molecules store energy, transport molecules from place to place and regulate its flow -Couple reactions together so that unfavorable reactions can occur at the expense of reactions that release energy Enzymes Protein catalysts Never used up Specific reactions require specific enzymes Enzymes lower activation energy barrier Enzymes speed up reaction 10 8 -10 20 times faster Do not reverse an energetically unfavorable reaction
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This note was uploaded on 04/19/2010 for the course BIOL 1201 taught by Professor Wishtichusen during the Spring '07 term at LSU.

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BIO1201 Test 2-1 - Flagella & Cilia Same structural...

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