fluid mosaic model
o accepted model of cell membrane structure, o membrane as a mosaic of diverse protein moleceules in a bilayer of phospholipid molecules.
Cell Membrane structure
-phospholipid bilayer, polar & non-polar
-Cell surface proteins, misonomer
-channel
-receptor
-cell surface marker
selective permeability
Membrane allows some substances to cross more easily than others
diffusion
tendency of particles to move from more concentrated regions to less concentrated regions!
passive transport
o The diffusion of a substance across a biological membrane with no energy.
osmosis
diffusion of water across a selectively permeable membrane.
tonicity
ability of a solution to cause a cell to gain or lose water
isotonic
o =
o cells volume remains constant
hypotonic
o solution with a solute concentration lower than that of a cell (too much water)
o cell gains to much water AND BURST
o In a plant cell, the plant becomes turgid and its very healthy!
hypertonic
o solution with a solute concentration higher than that of a cell (losing water)
o Plant and animal cells both shrivel up AND DIE
osmoregulation
control of water balance
facilitated diffusion
�diffusion through selective pores in the membrane, from high > low concentration
aquaporin
A transport protein in the plasma membrane of cells, where there is a very rapid diffusion of water in and out certain cells
active transport
o use of cellular energy to transport molecules through a membrane using some sort of energy!
Sodium potassium pump
o uses ATP to create a high concentration of sodium ions outside the cells
exocytosis
The movement of materials out of a cell, used to export bulky molecules!
endocytosis
Cellular takes in substances via formation of new vesicles from the plasma membrane.
phagocytosis
Cellular "eating"; a type of endocytosis in which a cell engulfs a particle by wrapping cell membrane around it
Pinocytosis
� "cellular drinking"
�Cell gulps droplets of fluid into tiny vesicles
receptor-mediated endocytosis
o uses receptors in a receptor-coated pit to interact with a specific protein, starting the formation of a vesicle.
energy
�capacity to perform work
kinetic energy
�energy of motion
thermal(heat) energy
Kinetic energy due to the random motion of atoms and molecules; energy in its most random form.
potential energy
�stored energy
chemical energy
� Energy available in molecules for release in a chemical reaction; a form of potential energy.
thermodynamics
� study of energy transformation that occurs in a collection of matter
first law of thermodynamics
�Energy can be transferred and transformed, but it cannot be created or destroyed.
entropy
A measure of disorder, or randomness.
second law of thermodynamics
�energy conversion reduces the order of the universe, increasing its entropy.
cellular respiration
�chemical process where oxygen is used to convert chemical energy stored in molecules ? chemical energy that the cell can use to work!
exergonic reaction
� chemical reaction that releases energy, energy released
endergonic reaction
�yields products that are rich in chemical energy, energy required
metabolism
�Total of an organism's chemical reactions.
metabolic pathway
A series of chemical reactions that either builds a complex molecule or breaks down a complex molecule into simpler compounds.
energy coupling
�use of energy released from an exergonic reaction to drive an endergonic reaction.
ATP
Adenosine triphosphate, the main energy source for cells.
phosphorylation
The transfer of a phosphate group, usually from ATP, to a molecule. Nearly all cellular work depends on ATP energizing other molecules by this transfer.
3 main types of cellular work
o chemical, phosphorylation of reactants provides energy to drive endergonic synthesis
o mechanical
o transport, ATP drives active transport of solutes across a membrane
Energy of activation
�amount of energy needed to push the reactant over an energy barrier, so the reaction can begin
Enzymes
�proteins that function as biological catalyst, increasing rate of reaction
Substrate
Specific reaction that an enzyme acts on
Active site
Substrate goes into a region of the enzyme
The catalytic cycle of an enzyme
1. Enzyme available with empty active site
2. Substrate binds to enzyme w/ induced fit
3.Substrate ? products
4.Products are released
Cofactors
nonprotein helpers
Coenzyme
Organic molecule
Non competitive inhibitor
Binds to the enzyme somewhere else, and it's binding changes the shape of the enzyme so that the active site no longer fits the substance
Competitive inhibitor
Reduces an enzymes productivity by blocking substrates from entering the active site
fluid mosaic model
o accepted model of cell membrane structure, o membrane as a mosaic of diverse protein moleceules in a bilayer of phospholipid molecules.
Cell Membrane structure
-phospholipid bilayer, polar & non-polar
-Cell surface proteins, misonomer
-channel
-receptor
-cell surface marker
selective permeability
Membrane allows some substances to cross more easily than others
diffusion
tendency of particles to move from more concentrated regions to less concentrated regions!
passive transport
o The diffusion of a substance across a biological membrane with no energy.
osmosis
diffusion of water across a selectively permeable membrane.
tonicity
ability of a solution to cause a cell to gain or lose water
isotonic
o =
o cells volume remains constant
hypotonic
o solution with a solute concentration lower than that of a cell (too much water)
o cell gains to much water AND BURST
o In a plant cell, the plant becomes turgid and its very healthy!
hypertonic
o solution with a solute concentration higher than that of a cell (losing water)
o Plant and animal cells both shrivel up AND DIE
osmoregulation
control of water balance
facilitated diffusion
�diffusion through selective pores in the membrane, from high > low concentration
aquaporin
A transport protein in the plasma membrane of cells, where there is a very rapid diffusion of water in and out certain cells
active transport
o use of cellular energy to transport molecules through a membrane using some sort of energy!
Sodium potassium pump
o uses ATP to create a high concentration of sodium ions outside the cells
exocytosis
The movement of materials out of a cell, used to export bulky molecules!
endocytosis
Cellular takes in substances via formation of new vesicles from the plasma membrane.
phagocytosis
Cellular "eating"; a type of endocytosis in which a cell engulfs a particle by wrapping cell membrane around it
Pinocytosis
� "cellular drinking"
�Cell gulps droplets of fluid into tiny vesicles
receptor-mediated endocytosis
o uses receptors in a receptor-coated pit to interact with a specific protein, starting the formation of a vesicle.
energy
�capacity to perform work
kinetic energy
�energy of motion
thermal(heat) energy
Kinetic energy due to the random motion of atoms and molecules; energy in its most random form.
potential energy
�stored energy
chemical energy
� Energy available in molecules for release in a chemical reaction; a form of potential energy.
thermodynamics
� study of energy transformation that occurs in a collection of matter
first law of thermodynamics
�Energy can be transferred and transformed, but it cannot be created or destroyed.
entropy
A measure of disorder, or randomness.
second law of thermodynamics
�energy conversion reduces the order of the universe, increasing its entropy.
cellular respiration
�chemical process where oxygen is used to convert chemical energy stored in molecules ? chemical energy that the cell can use to work!
exergonic reaction
� chemical reaction that releases energy, energy released
endergonic reaction
�yields products that are rich in chemical energy, energy required
metabolism
�Total of an organism's chemical reactions.
metabolic pathway
A series of chemical reactions that either builds a complex molecule or breaks down a complex molecule into simpler compounds.
energy coupling
�use of energy released from an exergonic reaction to drive an endergonic reaction.
ATP
Adenosine triphosphate, the main energy source for cells.
phosphorylation
The transfer of a phosphate group, usually from ATP, to a molecule. Nearly all cellular work depends on ATP energizing other molecules by this transfer.
3 main types of cellular work
o chemical, phosphorylation of reactants provides energy to drive endergonic synthesis
o mechanical
o transport, ATP drives active transport of solutes across a membrane
Energy of activation
�amount of energy needed to push the reactant over an energy barrier, so the reaction can begin
Enzymes
�proteins that function as biological catalyst, increasing rate of reaction
Substrate
Specific reaction that an enzyme acts on
Active site
Substrate goes into a region of the enzyme
The catalytic cycle of an enzyme
1. Enzyme available with empty active site
2. Substrate binds to enzyme w/ induced fit
3.Substrate ? products
4.Products are released
Cofactors
nonprotein helpers
Coenzyme
Organic molecule
Non competitive inhibitor
Binds to the enzyme somewhere else, and it's binding changes the shape of the enzyme so that the active site no longer fits the substance
Competitive inhibitor
Reduces an enzymes productivity by blocking substrates from entering the active site