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Definition
| he minimum amount of energy required to initiate a reaction. One source is heat, another is enzymes. |
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Term
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Definition
| They facilitate chemical reactions by lowering the Activation Energy required for the reaction to proceed. They do this by Moving the substrates closer together. Aligning the substrates in correct geometric orientation for the reaction. Promoting acid – base reactions between side chains of reactants. Effectively shutting out, or removing, H2O molecules from interfering with the reaction. |
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Definition
| Reactant molecules in reactions involving enzymes. |
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Term
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Definition
| The location on the enzyme where the substrate molecules temporarily bind, has a specific shape |
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Term
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Definition
| The binding of the enzyme to its specific substrate produces a change in the enzyme structure that allows the reaction to proceed at an accelerated rate. Induced state is not a perfect fit at the start. This is quite stable. |
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Term
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Definition
Optimal pH
Optimal temperature
Optimal salt concentration
Optimal Substrate concentration |
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Definition
| Enzyme involved in the breakdown of hydrogen peroxide to water and oxygen. Released from ruptured peroxisomes. |
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Definition
| Process of protein losing its three dimensional shape due to changes in pH and extreme temperatures. |
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Term
| “Passive” movement across membrane |
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Definition
Does not require energy (ATP).
This type of movement across the membrane is dependent on size, shape, charge, concentration difference, and kinetic energy (temperature) of molecules involved. |
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Term
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Definition
| : Diffusion that requires a carrier for small sugars (glucose), amino acids and similar-sized molecules. |
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Term
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Definition
This movement across a membrane or barrier requires the expenditure of energy (ATP) and a carrier protein.
Is the opposite of diffusion, the molecules move against (or upstream) the concentration gradient as opposed to moving downstream or down the concentration gradient. Involves the movement of small or large molecules. These carrier proteins tend to undergo a conformational change when they bind to their specific target molecule.
Are required in active transport and facilitated diffusion. |
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Term
| Examples of active transport |
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Definition
Endocytosis, such as Phagocytosis and Pinocytosis.
Exocytosis, such as the production and distribution of cellular product (insulin). |
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Term
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Definition
Materials coming into the cell via vesicle entry or sac formation.
Engulfing debris or nutrients into the cell.
The sac is derived from the cell membrane.
Phagocytosis: Cell eating
Pinocytosis: Cell drinking |
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Term
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Definition
Release of cellular products and / or cell waste via vesicule or sac fusion.
Synonymous with “secretion |
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Term
| Cell Membrane Structure and Concept |
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Definition
| Regulates the passage of molecules into and out of the cell. All cells are surrounded by a cell membrane. Considered a “dynamic, fluid, phospholipid bilayer”. Contains proteins imbedded in the membrane. Membrane also contains cholesterol which gives it the fluid, flexible, fatty property. Thus the model used to describe the membrane is called the “fluid-mosaic model” structure.(Fluid texture and movement. Randomly dispersed protein pattern.) |
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Term
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Definition
Possess various functions. Five types: Cell recognition: usually
glycoproteins such as the MHC proteins.
Critical for immune system function.
Organ transplants.
Multi-Histo Compatibility (MHC)
Channel: Allow for the proper flow of selected nutrients in and wastes out of the cell. Na+, K+, Cl-, Mg++ ions.
Transport system that spans the whole membrane. |
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Term
| Movement across membrane - General Principles |
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Definition
| Molecules usually cross the membrane by way of diffusion, carrier molecules, or vesicle formation. H2O moves freely across the membrane. Small non-polar molecules and gases (CO2, O2) also pass freely. Ions, large, and small, as well as polar molecules’ movement are restricted. The membrane is called “selectively permeable”. Also called a “semi-permeable” membrane. |
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