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14 Cards in this Set
- Front
- Back
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Growth Factors
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vitmins/precursors of nucleic acids
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Phototroph
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make everything for itself
-can synthesize all amino acids(20-21) -Nuceic acid precursors;vitamins (many bacteria) |
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Auxotrophs
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lack the ability to synthesize one or more
-amino acids nucleic acid precursors vitamins (humans, many bacteria, fungi, protists) |
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How are nutrients aquired from the environment?
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transporters
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Simple diffusion
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movnt of a molecule from a reqion of high concentration to one of low concentration.
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Rate dependent on what
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1)concentration gradient
2)area across which diffusion occurs |
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Facilitated diffusion
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-the involvement of a carrier molecule(usually a protein) in the movement(transport)
-saturability of the carrier can occur. |
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Glycerol Facilitation(limited)
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Facilitated diffuision in bacteria
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Active transport system
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-concentration of a molecule inside the cell
-energy is required. chemical(ion) gradient. ATP, PEP Major way bacteria use to gather nutrients from their environment. permease carriers/transporters |
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Uniport
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-one protein
-one substrate -one direction |
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symport
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-one protein
-one substrate -one ion direction -one direction(same) |
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Antiport
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-one protein
-one subtrate -(two) one ion gradient -two direction |
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Periplasmic Protein-dependent transport system
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-use ATP as souce of energy
-proteins in periplasm -bind sugar/amino acid(substrate) -"present) the subsrate to a carrier in cytoplasmic membrane. -activation of carrier hydrolysis of ATP transfer of substrate into cytoplasm. |
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Features of:
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high rates of transport
high affinity for substrates osmotic shock can reduce transport activity. |
