Cellular Basis of Physiology Flashcards
Categories of Protein Function
Catalysis, reaction coupling, transport, structure, signalling
Catalysis
ability to increase the rate of a chemical reaction without altering the equilibrium of the reaction
Reaction Coupling
2 reactions joined together with the transfer of energy. ex: hydrolysis
Transport
method for molecules to cross in and out of cells
Structure
glue cells together
Signalling
controlled change that transmits information
Mechanisms of allosteric shape change
ligand binding, phosphorylation, voltage-dependent proteins
Ligand Binding
binding of one ligand changes the binding site shape of a different ligand, inhibiting or activating its ability to dock with the protein
Phosphorylation
adding a phosphate group
Voltage-Dependent Proteins
the electrical field surrounding some proteins can change the conformation of some proteins
Molecules that can pass through lipid bilayer
small polar molecules, non-polar molecules (including water and urea)
Molecules that cannot pass through lipid bilayer
ions, polar molecules larger than 100 daltons
Factors that determine the driving forces of molecules across cell membranes
chemical concentration, electrical gradient, pressure (gravity and hydrostatic pressure from heart pump)
Osmosis
movement of water across cells and capillaries
Colloidal (oncotic) pressure
the osmotic pressure resulting from dissolved blood proteins
Facilitated Diffusion
use of transport proteins to move from high to low. Ungated channel proteins, carrier proteins, ligand-gated channel, voltage-gated channel
Ungated Channel Proteins
have a hole for small ions to travel through
Carrier Proteins
have specific binding site
Ligand-Gated Channel
channel opens when specific ligand binds
Voltage-Gated Channel
channel opens based on the electrical field surrounding the channel
Secondary Active Transport
a. The active movement of glucose into the cell is paired with the passive movement of sodium into the cell. The concentration of sodium remains low thanks to the active transport out of the cell by the Na/K ATPase pump
Active Transport
hen 3 sodiums bind, the pump changes conformation and becomes phosphorylated through hydrolysis of ATP. This changes conformation again so that the sodium molecules are released outside the cell and potassium ions from outside the cell now bind the transporter. When two potassium ions are bound conformation changes again and the transporter loses its phosphate and releases potassium to the inside of the cell
