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14 Cards in this Set

  • Front
  • Back
Growth Factors
vitmins/precursors of nucleic acids
make everything for itself
-can synthesize all amino acids(20-21)
-Nuceic acid precursors;vitamins
(many bacteria)
lack the ability to synthesize one or more
-amino acids
nucleic acid precursors
(humans, many bacteria, fungi, protists)
How are nutrients aquired from the environment?
Simple diffusion
movnt of a molecule from a reqion of high concentration to one of low concentration.
Rate dependent on what
1)concentration gradient
2)area across which diffusion occurs
Facilitated diffusion
-the involvement of a carrier molecule(usually a protein) in the movement(transport)
-saturability of the carrier can occur.
Glycerol Facilitation(limited)
Facilitated diffuision in bacteria
Active transport system
-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
-one protein
-one substrate
-one direction
-one protein
-one substrate
-one ion direction
-one direction(same)
-one protein
-one subtrate
-(two) one ion gradient
-two direction
Periplasmic Protein-dependent transport system
-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.
Features of:
high rates of transport
high affinity for substrates
osmotic shock can reduce transport activity.