Foundations of Biology 221, Week 5 Notes
Foundations of Biology 221, Week 5 Notes BIOL 221 - 001
Popular in Foundations of Biology I
Popular in Biology
verified elite notetaker
This 4 page Class Notes was uploaded by reyestl9108 Notetaker on Thursday October 13, 2016. The Class Notes belongs to BIOL 221 - 001 at University of Wisconsin - Eau Claire taught by Daniel P. Herman, Julie A. Anderson in Fall 2015. Since its upload, it has received 8 views. For similar materials see Foundations of Biology I in Biology at University of Wisconsin - Eau Claire.
Reviews for Foundations of Biology 221, Week 5 Notes
Report this Material
What is Karma?
Karma is the currency of StudySoup.
You can buy or earn more Karma at anytime and redeem it for class notes, study guides, flashcards, and more!
Date Created: 10/13/16
Transporting Solutes Across Cell Membrane: Transport requires transport proteins Transport Proteins- transmembrane proteins specific to certain molecules Proteins will undergo conformational change (change shape as they perform their function) Channels - pathways the molecules flow through usually gated opens and closes in response to ligands (extracellular signaling molecules) or change in membrane potential (charge +-) molecules move through according to diffusion 1. Transporters bind (polar)molecules in a hydrophilic pocket 2. Conformation change moves molecules across membrane (ATP is required for active transport) Gated Channels: Chemically gated: -Receptors (binding sites) receive ligands and gate opens Voltage gated: -Ion charge interacts with charge on membrane -Positively charged extracellular membrane may not let positively charged ions through (already enough positive charge) Types of Transporters: Uniporter-single solute moves in one direction of membrane Symporter-two (potentially different) solutes move in the same direction Antiporter-two solutes move in opposite directions (movement of one solute flips transporter to other side where it receives other solute, flipping back over. This can be used as a tool for equilibrium) Active Transport-transport that requires energy Primary Active Transport: -directly uses ATP in transporter proteins to transport against a concentration gradient Secondary Active Transport: -uses kinetic energy of one solute as it moves naturally along a concentration gradient in order to drive an active transport of another solute against its concentration gradient ATP-Binding Cassette Transport Proteins 1. 2 ATP enter transport protein (these can wait without hydrolyzing) 2. MalE binds to maltose outside of the cell and delivers to transport protein 3. Transport protein’s closed confirmation undergoes conformational change to become open confirmation 4. Conformational change causes hydrolysis of ATP 5. ADP+Pi are released and maltose is delivered inside the cell ABC transport proteins are found in all prokaryotes and eukaryotes Periplasm- gel-like material between cytoplasm and membrane Sodium/Potassium Pump (voltage gated transport) -primary active transport -ATP is used to create a steep concentration gradient, causing Na+ to come back into cell How the electrochemical gradient is established: 1. Na+ sits inside transporter 2. ATP arrives at cytoplasmic (inner) leaflet 3. ATP is hydrolyzed by external ‘roaming’ proteins 4. Phosphate released from ATP attaches to cytoplasmic side causing an E2 state to occur in transporter (In E1 state the extracellular side is closed and cytoplasmic side is open. In E2 cytoplasmic is open/extracellular is closed) 5. Na+ is released outside the cell 6. Phosphate holds E2 state and allows K+ to enter 7. K+ ions cause phosphate to release Important Functions of Ion Electrochemical Gradients: transport of ions and molecules production of energy intermediates osmotic regulation neuronal signaling muscle contraction bacterial swimming (flagellas) Proton Motive Force- uses energy of electrons from electron carrier to pump protons with electron transport chain (used for flagella) Simple Transport- driven by energy in proton motive force Group Translocation- provides a one way concentration gradient/uses phosphoenolpyruvate as energy Intercellular Transport -utilizes gap junctions (small gaps between cell membranes of adjacent cells) -formed using integral membrane protein subunits called connexins (animals) or innexins (invertabrates) -gap junctions are called either connexons or innexons -connexons/innexons transport ions and small signaling molecules ex. amino acids, sugars, Ca2+, cAMP Plasmodesmata: connect cytoplasm of adjacent cells -can shrink and expland -shrink when plant is wounded -expand to allow for transfer of macromolecules between cells (lipids synthesized in one cell can be shared to another) Exocytosis (export of material out of cell): 1. protein modified in lumen of golgi binds to membrane wraps around vesicle and is loaded with cargo 2. vesicle is released form golgi with cargo molecules 3. protein coat is shed 4. vesicle fuses with plasma (cell) membrane and releases molecules into extracellular environment (outside) Endocytosis: import of material into cell Adherens Junction- cell-cell junction attached to actin cytoskeleton Desmosome- a structure which two adjacent cells are attached, formed from protein plaques in the cell membranes linked by filaments (use desmogleins) Hemidesmosome- one cell is attached to extracellular matrix and uses integrins Cell Communication Responds to: -nutriets -temperature -pH -osmotic conditions -light -oxygen availability Communicates to other cells: -immune response -muscle contraction -sensing/regulating cell density -nerve transmission -growth and development -injury response Themes of Communication: -cell membrane receptor (antenna that detects specific signal) -extracellular signal (specific signaling molecules or environmental stimulus) -activation of a signal transduction pathway (passes the extracellular message to the inside) -cellular response differential gene expression (activation/deactivation of genes) changing enzyme activity (alters metabolism or other cell functions) changing cell shape or movement (affects structural proteins) Types of Communication -direct intercellular signaling (signal passes through intercellular channels from cytosol in adjacent cells) -contact-dependent signaling (membrane bound signals bind to receptors on adjacent cells) -autocrine signaling (cells release signals that affect themselves and nearby target cells) -paracrine signaling (cells signals that affect nearby target cells) -endocrine signaling (cells release signals that travel long distances to affect target cells)
Are you sure you want to buy this material for
You're already Subscribed!
Looks like you've already subscribed to StudySoup, you won't need to purchase another subscription to get this material. To access this material simply click 'View Full Document'