Cell Membrane, Membrane Transport, and Membrane Potential Flashcards
______ functions to Separate cytoplasm from ECF, Regulate exchange between ECF and Cytoplasm, Communicate with other cells, and Provide structural attachments between cells or between cell and extracellular matrix.
Plasma Membrane
Plasma membrane structure is described by ____ model
Fluid Mosaic Model
What are the 4 different types of organic molecules that make up the plasma membrane?
phospholipids, steroids, proteins, and carbs
______ are Amphipathic, Organized into a bilayer, and Functions: Creates Barrier
Phospholipids
What are the heads of phospholipid polar or non-polar?
Polar
What are the tails of phospholipid polar or non-polar?
Non-polar
Hydrophobic substances: Small, nonpolar molecules, Ex. (Gases (O2, CO2), Fatty acids, steroids, Lipophilic substances•Ex. Ethanol, and Water are _______ for phospholipids (Permeable or non-permeable)
Permeable
Larger molecules, Polar molecules, and Charged substances (Glucose, Ions, Amino acids, and Proteins) are _____ for phospholipids (Permeable or non-permeable)
Non-permeable
_____ are incorporated into plasma membranes Help keep membrane fluid over a wide range of temperatures and Help to make membrane water tight
Cholesterol
For proteins ____ determines function
Shape
What are the factors that alter protein shape?
Mutations, pH, Temp, Osmolality, and Covalent/Allosteric Modulation
A mutation alters the ____ structure of the protein
Primary
Changes in ph, Temp, or Osmolaltiy alters the ______ structures of the proteins and causes _____
Secondary, Tertiary, and Quaternary; denaturation
Covalent/Allosteric Modulation changes the ____ structures of a protein
Secondary, Tertiary, and Quaternary
What are the 3 structural classifications of a protein?
Transmembrane, Integral, and Peripheral
______ Bind to specific chemical signals (ligands) and transmit that information to the cytoplasm
Receptors
Shape of the binding site determines what will bind; Each type of protein, in general, will interact with only one type of substance or class of substances
Specificity
______ refers to the fraction of total binding sites that are occupied at any given time; Dependent on [protein] and the [substance]
Saturation
A _______ is a chemical substance (exogenous ligand) that binds to the active site of the protein and blocks the endogenous ligand from binding
competitive inhibitor
A chemical substance that comes from outside the body
exogenous ligand
A _____ will also activate a receptor
agonist
A ____ will block receptor activity
antagonist
Response of a cell to a chemical signal is _____ mediated
receptor mediated
If there is no receptor, there is ____ response
no response
If 2 different ligands bind to the same response, they will elicit _____ response
same response
If one ligand binds to 2 different receptors, it will elicit ____ response
2 different responses
Strength/Ease of ligand-receptor binding; proportionate to # ligands bound to receptors at any given
Receptor Affinity
____ is the ligand concentration where half of the receptors are occupied
Kd
Affinity is ____ to Kd
inversely related
Transmembrane proteins with a 3D shape that forms a tiny fluid filled pore connecting ECF and Cytoplasm
Channels
_______ function in Facilitated diffusion of ions into and out of cell (passive; does not require energy); Can be somewhat specific (Ca++ channel, Na+ channel, Cl-channel, cation channel, etc.)
Channels
Always open and ions freely flow through via facilitated diffusion; Creates “Leak Currents”
Open Channels
Spend most of their time in the closed state, and will open only when stimulated; Three types: a. Chemically gated b. Mechanically gated c. Voltage gated
Gated Channels
____ modulation is seen in ligand-gated channels; displays non-covalent bonding and don’t need a catalyst
Allosteric modulation
____ modulation uses kinases and phosphatases; displays covalent bonding and needs a catalyst
Covalent modulation
Transmembrane protein that moves hydrophilic building blocks across the plasma membrane via facilitated diffusion (passive; does not require energy); changes shape
Carriers
Transmembrane protein that moves ions and hydrophilic building blocks across the plasma membrane via active transport (Active; requires energy).
Active Transporters
____ proteins Forms cell to cell attachments that hold adjacent epithelial cells together
Structural Proteins
_____ junctions Prevents intercellular movement of fluid and dissolved substances
Tight Junctions
_____ are junctions for Structural Support
Desmosomes
_____ junctions function in Cell to Cell communication via ions
Gap Junctions
Integral membrane, transmembrane, or peripheral membrane proteins that catalyze specific chemical reactions either on the extracellular surface of cell or inside cell.
Enzymes
______ are Attached to extracellular surface of membrane lipids and proteins
Carbohydrates
made up of Glycolipid and carbs; Plays important role in enabling cells to identify and interact with each other.
Glycocalyx
In ____ transport, No energy required; Down gradients (high to low; ΔC, ΔP or ΔE); Types-Diffusion-Osmosis-Bulk Flow
Passive Transport
In ____ transport, Energy required; Up gradients (low to high); Types-Active Transporters-Bulk (Vesicular) Transport
Active Transport
Molecules in a fluid are continuously and randomly bouncing aroundRate of movement proportional (T) and inversely related to (Mass)
Random thermal motion –
Movement of substances other than water down a gradient (ΔC; ΔE or ΔP; high to low). Net movement stops at equilibrium, Random movement is continuous, and is Substance specific
Diffusion