Term
| Why is transport important? |
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Definition
Natural Gradients
Food/Oxygen/CO2
Unnatural Gradients
Excitability
Cells create an unequal distribution of ions across a cell membrane to store membrane potential for responsiveness
Membranes do this with the help of proteins |
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Term
| Transport Proteins: Recall that- |
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Definition
The membrane is hydrophobic-
There are proteins in the membrane |
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Definition
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Definition
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Term
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Definition
No cellular energy (ATP) required
Substance moves down its concentration gradient |
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Term
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Definition
Energy (ATP) required
Occurs only in living cell membranes |
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Term
| What determines whether or not a substance can passively permeate a membrane? |
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Definition
Lipid solubility of substance
Channels of appropriate size
Presence of Carrier proteins |
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Term
| Passive Processes: Simple Diffusion |
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Definition
| Nonpolar lipid-soluble substances diffuse directly through the phospholipid bilayer |
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Term
| Certain molecules (glucose, amino acids, and ions) use carrier proteins or channel proteins which: |
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Definition
Exhibit specificity (selectivity)
Rate is determined by number of carriers or channels which assists to regulate activity and quantity |
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Term
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Definition
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Term
| Transmembrane integral proteins transport: |
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Definition
| specific polar molecules (sugars and amino acids) |
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Term
| Binding of substrate causes: |
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Definition
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Term
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Definition
| Aqueous channels formed by transmembrane proteins selectively transport ions or water |
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Term
| Facilitated Diffusion Two types: |
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Definition
Leakage channels - Always open
Gated channels - Controlled by chemical or electrical signals |
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Term
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Definition
| Movement of a solvent across a selectively permeable membrane |
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Term
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Definition
| isotonic environment happens when an equal concentration exists inside and outside the cell |
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Term
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Definition
| greater solute concentration within cell |
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Term
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Definition
| greater solute concentration outside cell |
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Term
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Definition
Simple diffusion
Facilitated diffusion
osmosis |
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Term
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Definition
use energy (ATP) for membrane transport
Two types of active processes:
Active transport
Vesicular transport |
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Term
| active transport requires: |
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Definition
| carrier proteins (solute pumps) |
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Term
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Definition
| Moves solutes against their concentration gradient |
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Term
| Types of active transport: |
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Definition
Primary active transport
Secondary active transport |
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Term
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Definition
Na+- K+ ATP
Located in all plasma membranes
Involved in primary and secondary active transport of nutrients and ions
Maintains electrochemical gradients (or membrane potential) essential for functions of muscle and nerve tissues |
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Term
| Secondary Active Transport |
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Definition
Depends on an ion gradient created by primary active transport
Energy stored in ionic gradients is used indirectly to drive transport of other solutes |
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Term
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Definition
Transport of large particles, macromolecules, and fluids across plasma membranes
Requires cellular energy (ATP) |
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Term
| Vesicular Transport 3 types: |
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Definition
Exocytosis - transport out of cell
Endocytosis - transport into cell
Transcytosis - transport into, across, and then out of cell |
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Definition
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Definition
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Definition
| transport into, across, and then out of cell |
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Term
| Substance (vesicular) trafficking - |
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Definition
| transport from one area or organelle in cell to another |
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Term
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Definition
| solids pseudopods engulf solids and bring them into cell’s interior |
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Term
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Definition
| plasma membrane infolds, bringing extracellular fluid and solutes into interior of the cell |
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Term
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Definition
| material being moved out of the cell |
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Term
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Definition
| Separation of oppositely charged ions across a membrane creates a membrane potential |
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Term
| Resting Membrane Potential (RMP): |
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Definition
Voltage measured in resting state in all cells Results from diffusion and active transport of ions (mainly Na+ and K+)
Sodium / Potassium pump maintains the RMP! |
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Term
| Important Roles of Cell Adhesion Molecules |
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Definition
Anchor cells to extracellular matrix or to each other
Assist in movement of cells past one another
-CAMs of blood vessel lining attract white blood cells to injured or infected areas
Stimulate synthesis/decom. of adhesive membrane junctions
Transmit intracellular signals to direct cell migration & proliferation |
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Term
| Important Roles of Cell Membrane Receptors |
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Definition
Contact signaling - touching and recognition of cells like in an immune response
Chemical signaling - interaction between receptors in neurotransmitters and hormones
Alter activity of cell proteins allowing enzymes or chemically gated ion channels to become active
G proteins - receptors affecting an ion channel or enzyme or causing the release of an internal second messenger – thus more intracellular responses |
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Term
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Definition
| touching and recognition of cells like in an immune response |
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Definition
| interaction between receptors in neurotransmitters and hormones |
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Term
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Definition
| receptors affecting an ion channel or enzyme or causing the release of an internal second messenger – thus more intracellular responses |
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