Module 2 Vocab Flashcards
Lipid Bilayer
The membrane structure of the plasma membrane in a cell, ~ 5 nm thick
Phopholipids
The basic component of the plasma membrane, is amphipathic witha hydrophillic head and hydrophobic tail
Fluid mosaic model
Membrane model which suggests that proteins and lipids can move freely laterally in the membrane
Membrane fluidity
Determines the ability of particles to move about in a membrane laterally
FRAP
Fluorescence recovery after photobleaching; used to study membrane protein diffusion
SPT
Single particle tracking microscopy; tracks the movement of a particel tagged with a gold flake
Integral membrane proteins
Includes transmembrane, monolayer-associated, and lipid-linked proteins; proteins that are embedded into the membrane directly
Peripheral Membrane Proteins
Only includes rotein attached proteins; proteins indirectly bound to the membrane
Transmembrane domain
Portions of a protein that tend to form alpha helices with hydrophobic side chains, allowing them to span the membrane favorably
Passive Transport
Transport through a cell that happens without the addition of energy
Active Transport
Transport through a cell that requires teh addition of an energy source
Diffusion
A form of passive transport that uses concentration gradients to move molecules
Facilitated Diffusion
Passive transport of molecules through a channel in the membrane
Rate of diffusion across a membrane
Dependent on molecule size, charge, solubility, membrane viscosity, concentration gradient, receptor/channel protein density, and cell temperature
Osmosis
Movement of water from low to high solute concentration
Isotonic
Concentration equilibrium or maintained
Hypotonic
Dilute solution
Hypertonic
Highly concentrated solution
Coupled Transporter
Active transport method that moves a type of molecule out of the cell and at least one different molecule into the cell
ATP-Driven pump
Uses ATP as an energy source to transport molecules against their concentration gradient into or out of a cell
Light-driven pump
Uses energy from light to drive molecules against their electrochemical gradient
Uniporter
Transports one molecule in one direction
Symport
A type of coupled transport that co-transports different molecules
Antiport
A type of coupled transporter that transport one molecule in and one out
Coupled Transporter
Exploit the energy stored in electrochemical gradients of one solute to drive the pumping of another solute against its gradient
ABC Transporters
ATP binding cassette transporters; use the energy of ATP hydrolysis to switch conformations
Signal Sequences (SS)
20-22 amino acid sequences located mostly at the N-terminus of proteins with a long hydrophoic stretch followed by a charged amino acid; indicates where a protein goes in the cell
Smooth endoplasmic reticulum (SER)
Synthesizes and secretes hormones, detoxifies organic compounds
Sarcoplasmic reticulum
SER in muscle cells that stores and releases Ca++
Rough Endoplasmic
Site of synthesis of specific proteins
Co-Translational Translocation
Protein enters the ER as it is being synthesized
Post-Translational Translocation
Proteins that enter the ER after they are synthesized
Translocator Protein
A protein that binds to the signal sequence of a growing soluble protein and deposits it into the ER
Signal Peptidase
Cleaves the signal sequence of a protein following its translocation into the ER
Signal Recognition Particle (SRP)
A complex of 6 polypeptides and 1 cytoplasmic RNA that binds to the signal sequence; when bound to the SS temporarily halts translation
SRP Receptor
Binds to the SRP and allows the SS to complex with the protein translocator
N-terminus
The terminus of the protein that faces the inside of the ER lumen
Transmembrane Proteins
Proteins that span across the plasma membrane of a cell or organelle; part of their protein is in the cytoplasm, part in ER lumen during synthesis (N-terminus)
STOP Transfer Sequence
Transmembrane domains of proteins that halt their movement through a membrane during synthesis
Hydropathy Plot
A plot that shows the number of transmembrane domains in a protein