Module 1 - Cell Physiology.pdf

HH/KINE 2011 - HUMAN PHYSIOLOGY I FACULTY OF HEALTH KINESIOLOGY AND HEALTH SCIENCE Fall 2024 MODULE 1 – CELL PHYSIOLOGY Human Physiology: From Cells to Systems, 5th Edition Lauralee Sherwood; Christopher Ward; Chapter 2 Lecture 1: Learning Objectives...

HH/KINE 2011 - HUMAN PHYSIOLOGY I FACULTY OF HEALTH KINESIOLOGY AND HEALTH SCIENCE Fall 2024 MODULE 1 – CELL PHYSIOLOGY Human Physiology: From Cells to Systems, 5th Edition Lauralee Sherwood; Christopher Ward; Chapter 2 Lecture 1: Learning Objectives By the end of today’s lecture, you should be able to: Understand the principle of cell theory Define the main structures and functions of a cell Identify the organelles present in all human cells and learn their function(s) Copyright © 2024 Dr. Abdul-Sater Principles of cell theory Theodor Schwann The cell is the smallest structural and functional unit capable of carrying out life processes. The functional activities of each cell depend on the specific structural properties of the cell. Cells are the living building blocks of all plants and animals organisms. The cell is the basic unit of life. An organism’s structure and function ultimately depend on the collective structural characteristics and functional capabilities of its cells. Because of this continuity of life, the cells of all organisms are fundamentally similar in structure and function. Copyright © 2024 Dr. Abdul-Sater Cell Structure and Function Trillions of cells in the human body classified Peroxisome into ~ 200 cell types Mitochondria Free ribosome This is based on specific variations in Vault Nuclear pore structure and function Nucleus Despite variations, Rough ER Pair of centrioles cells still share many in centrosome Ribosome (attached to Endoplasmic rough ER) reticulum Lysosome common features: Smooth ER Plasma Microtubules radiating from Membrane centrosome Microfilaments Cytosol Vesicle Plasma membrane Nucleus Golgi complex Cytosol ❙ Figure 2-1 Diagram of cell structures visible under an electron microscope. Copyright © 2024 Dr. Abdul-Sater Cell Structure and Function Plasma Membrane: thin membranous structure that encloses each cell composed mostly of lipid (fat) molecules (bilayer) studded with proteins barrier separates the cell’s contents from its surroundings selectively control movement of molecules into and out of the cell Copyright © 2024 Dr. Abdul-Sater Cell Structure and Function Nucleus: surrounded by a double- layered membrane houses the cell’s genetic material, deoxyribo- nucleic acid (DNA) Serves as a genetic blueprint during cell replication Directs protein synthesis Copyright © 2024 Dr. Abdul-Sater Cell Structure and Function: Organelles Endoplasmic reticulum Fluid filled membranous system Ribosomes a protein and lipid Where a messenger RNA fits through Rough ER Smooth ER producing factory a ribosome Large Small Rough ER: ribosomal subunit ribosomal subunit Studded with ribosomes (c) Ribosome Rough ER lumen Smooth ER lumen synthesizes proteins to be secreted to the exterior or to be Ribosomes incorporated into plasma membrane or Sacs Tubules other cell components Smooth ER: Don W. Fawcett/Science Source packages the secretory product into transport vesicles, which bud off and move to the Golgi complex Copyright © 2024 Dr. Abdul-Sater Rough ER lumen Ribosomes Smooth ER lumen Cell Structure and Function: Organelles Golgi ComplexUbiquitin 1 Addition of ubiquitin to consists of a stack of Unwanted a protein. flattened, protein slightly curved, membrane-enclosed sacs closelyRegulatory associated with the particle Golgi complex ER Unfolding Transport Modifies, Proteasome protein Core packages, and 2 Proteasome recognizes ubiquitin-tagged protein and vesicle from distributes (size of a ribosomal particle newly synthesized unfolds it. Enzymes that are part of the core digest ER, about to fuse with the Golgi proteins subunit) Peptides protein to small peptides. Golgi membrane lumen 3 Cytosolic enzymes Golgi degrade the released sacs Vesicles containing peptides to amino acids, finished product which are recycled for protein synthesis or used as an energy source. Golgi complex Proteasome and ubiquitin are recycled. ❙ Figure 2-4 Proteasome. Copyright © 2024 Dr. Abdul-Sater Cell Structure and Function: Organelles from the surface m Lysosomes Peroxisome pinocytosis provid brane that has been small, membrane-enclosed, degradative organelles Receptor-Media involves the nonsel break down organic Lysosome tor-mediated end molecules with powerful enables cells to imp its environment. R hydrolytic enzymes the binding of a sp digestive system of the cell: Oxidative surface membrane 2-9b). This binding destroy foreign substances Hydrolytic enzymes pocket inward and and cellular debris enzymes molecule inside the clathrin molecules, on the inner surface contrast to the outw resulting pouch is k Don W. Fawcett/Science Source clathrin. Cholestero lin, and iron are exa by receptor-mediat Unfortunat exploiting t HIV, the vi ❙ Figure 2-8 Lysosomes and peroxisomes. Diagram and electron micrograph to cells via Copyright © 2024 Dr. Abdul-Sater of lysosomes, which contain hydrolytic enzymes, and peroxisomes, which contain Cell Structure and Function: Organelles from the surface m Peroxisomes Peroxisome pinocytosis provid brane that has been membrane-enclosed sacs containing oxidative Receptor-Media enzymes Lysosome involves the nonsel tor-mediated end detoxify various wastes enables cells to imp its environment. R produced within the cell or the binding of a sp foreign toxic compounds Oxidative surface membrane 2-9b). This binding that have entered the cell Hydrolytic enzymes pocket inward and (e.g. alcohol consumed in enzymes molecule inside the beverages!) clathrin molecules, on the inner surface contrast to the outw resulting pouch is k Don W. Fawcett/Science Source clathrin. Cholestero lin, and iron are exa by receptor-mediat Unfortunat exploiting t HIV, the vi ❙ Figure 2-8 Lysosomes and peroxisomes. Diagram and electron micrograph to cells via Copyright © 2024 Dr. Abdul-Sater of lysosomes, which contain hydrolytic enzymes, and peroxisomes, which contain  Cell Structure and Function: Organelles Actin Keratin protofibril subunit Centrioles icrotubule A (b)pair of cylindrical Microfilament (c) Keratin, an intermediate filament structures at right angles to each other Centrioles rotubules help form and asymmetric maintain organize cell pes and play a role in complex cell microtubules during vements. assembly of the mitotic otubules are the largest of the cytoskeletal elements. They lender (22 nm in spindle diameter), during cell long, hollow, division unbranched composed primarily of tubulin, a small, globular, protein form cilia and flagella cule (❙ Figure 2-19a). Microtubules arise from the centrosome and its associated ioles. The centrosome, or cell center, located near the us, consists of the centrioles surrounded by an amorphous of proteins. The centrioles, which are nonmembranous nelles, are a pair of short cylindrical structures that lie at angles to each other at the centrosome’s center (❙ Figure. The centrosome is the cell’s main microtubule organizing Microtubule r. When a cell is not dividing, microtubules are formed triplet the amorphous mass and radiate outward in all directions the centrosome (see ❙ Figure 2-1, p. 23). Centrioles form Copyright © 2024 Dr. Abdul-Sater Cell Structure and Function: Organelles much of the energ Mitochondria folds of the inner available for housin rod-shaped or oval structures sists of a concentr about the size of bacteria solved enzymes tha tion of usable ener enclosed by a double Mitochondrion membrane Mitochondria in some cell t inner membrane forms a In skeletal muscle series of infoldings called Intermembrane space rarely exist separat work, the mitocho cristae Cristae nized system efficie ating energy—for e Cristae project into an inner acids—from the ce cavity filled with a gel-like acids, which are po thus can move mo solution known as the matrix rounding the inte watery cytosol. The mitochond changes through o vidual mitochondr Proteins of Inner Matrix Outer ing on the cell’s en electron transport mitochondrial mitochondrial network expands in system membrane membrane skeletal muscle. Copyright © 2024 Dr. Abdul-Sater Cell Structure and Function: Organelles much of the energ Mitochondria folds of the inner available for housin energy organelles, or “power sists of a concentr plants” of the cell solved enzymes tha tion of usable ener extract energy from the Mitochondrion nutrients in food and transform Mitochondria in some cell t it into a usable form for cell In skeletal muscle activities (ATP = Adenosine Intermembrane rarely exist separat space Tri-Phosphate) Cristae work, the mitocho nized system efficie Contain enzymes for citric acid ating energy—for e acids—from the ce cycle (TCA) and electron acids, which are po transport chain thus can move mo rounding the inte watery cytosol. The mitochond changes through o vidual mitochondr Proteins of Inner Matrix Outer ing on the cell’s en electron transport mitochondrial mitochondrial network expands in system membrane membrane skeletal muscle. Copyright © 2024 Dr. Abdul-Sater Lecture 2: Learning Objectives By the end of today’s lecture, you should be able to: Understand the three components of the cytoskeleton and their functions Know the composition of the cytosol Explain what cellular metabolism is Identify the stages of cellular respiration Understand the glycolytic pathway Copyright © 2024 Dr. Abdul-Sater Cell Structure and Function: Cytoskeleton Microtubules “bone and muscle” of the cell Long, slender, hollow tubes composed of tubulin molecules Maintain asymmetric cell shapes and coordinate complex cell movements highways for transport of secretory vesicles within cell main structural and functional component of cilia and flagella Keratin filament position cytoplasmic organelles (ER, Golgi complex, lysosomes, and mitochondria) assemble into mitotic spindle Keratin subunit Tubulin subunit Keratin Actin protofibril subunit © 2014 Nature Education All rights reserved (a) Microtubule (b) Microfilament (c) Keratin, an intermediate filament Copyright © 2024 Dr. Abdul-Sater Cell Structure and Function: Cytoskeleton Copyright © 2024 Dr. Abdul-Sater Cell Structure and Function: Cytoskeleton Microfilaments Smallest elements of the cytoskeleton ❙ Figu Keratin Intertwined helical chains of actin molecules; filament tubul tubes microfilaments composed of myosin molecules also tubul toske wrap present in muscle cells found A pro Play a vital role in various cellular contractile systems, gered filam bules including muscle contraction and amoeboid movementTubulin Keratin subunit (WBC or fibroblasts); serve as a mechanical stiffener for subunit microvilli Intermediate filaments Actin subunit Keratin protofibril Irregular, threadlike proteins Help resist mechanical stress (a) Microtubule (b) Microfilament (c) Keratin, an intermediate filament Microtubules help maintain asymmetric cell shapes and play a role in complex cell movements. Microtubules are the largest of the cytoskeletal Copyright elements. TheyDr. Abdul-Sater © 2024  by a regulatory particle Cell Structure Vaults and Function: Shaped like hollow octagonal barrels Cytosol Serve as cellular trucks for transport from nucleus to cytoplasm Centrioles A pair of cylindrical structures at right Form and organize microtubules during assembly of angles to each other the mitotic spindle during cell division and form cilia and flagella Cytosol Intermediary metabolism Dispersed within the cytosol Facilitate intracellular reactions involving degradation, enzymes synthesis, and transformation of small organic molecules Transport, secretory, and Transiently formed, membrane-enclosed Transport or store products being moved within, out endocytic vesicles products synthesized within or engulfed by of, or into the cell, respectively the cell Inclusions Glycogen granules, fat droplets Store excess nutrients Cytoskeleton As an integrated whole, serves as the cell’s “bone and muscle” Microtubules Long, slender, hollow tubes composed of Maintain asymmetric cell shapes and coordinate tubulin molecules complex cell movements, specifically serving as Cytosol = Cell Gel highways for transport of secretory vesicles within cell, serving as main structural and functional component of cilia and flagella, and assembling into mitotic spindle Microfilaments Intertwined helical chains of actin Play a vital role in various cellular contractile molecules; microfilaments composed of systems, including muscle contraction and amoeboid myosin molecules also present in muscle movement; serve as a mechanical stiffener Copyrightfor © 2024 Dr. Abdul-Sater Cellular Metabolism Intermediary Metabolism refers collectively to the large set of chemical reactions inside the cell that involve the degradation, synthesis, and transformation of small organic molecules such as simple sugars, amino acids, and fatty acids Energy providing the raw materials Used for cell activities needed to maintain the cell’s structure, function, and growth The intermediary metabolism occurs in the cytosol and involves thousands of enzymes. Anabolic processes Degradation Synthesis breakdown buildup Catabolic processes Copyright © 2024 Dr. Abdul-Sater  Cellular Metabolism: ATP The source of energy for the body is the chemical energy stored in the carbon bonds of ingested food Has to be extracted by the cell machinery and converted into a source of energy usable by the cell = high-energy phosphate bonds of Adenosine TriPhosphate or ATP Body’s common energy “currency” Cells “cash in” ATP to pay the energy P i “price” for: Maintaining structure, function and growth Pi P i P i A A P P + i i ATP ADP Energy for cells How is the ATP produced in the cell? Creatine phosphate (CP) Pi Energy from food Anaerobic glycolysis Aerobic metabolism Most of the ATP production solution’s molarity! Osmolarity (osmol/L) involves total amount of solutes present Molarity (mol/L) involves concentration of the compound as a whole. For instance: NaCl once dissolved in water separates into its ions as Na+ and Cl– If NaCl concentration is 200 mmol/L (mM) at the start upon the dissolution in water molarity remains 200 mM but osmolarity increases to 400 mosmol/L. We have to consider the total number of solutes in solution (i.e. the separated ions: 200 mosmol/L of Na+ and 200 mosmol/L of Cl–). Copyright © 2024 Dr. Abdul-Sater Membrane Transport: assisted membrane transport Large, poorly lipid-soluble molecules can not cross the plasma membrane on their own (Some of these molecules are essential nutrients; e.g. glucose) Two different mechanisms: Carrier-mediated transport (for small water-soluble molecules) Vesicular transport (larges molecules and multi-molecular particles) Copyright © 2024 Dr. Abdul-Sater Membrane Transport: assisted membrane transport 1. Carrier-Mediated Transport Carrier proteins span the plasma membrane They can reverse shape so binding sites are alternately exposed to the ECF and ICF (flip-flops) Three important characteristics: Specificity (amino acids cannot bind to glucose carriers) Saturation (limited number of carrier binding sites) Competition (closely related compounds compete for access) Copyright © 2024 Dr. Abdul-Sater Membrane Transport: assisted membrane transport Carrier-Mediated Transport - Two forms: Active or Passive Transport Facilitated diffusion: uses a carrier molecule to facilitate (assist) the transfer of a substance across the membrane from high to low concentration (downhill) Passive process (Does not require energy) Occurs naturally down a concentration gradient Rate is limited by saturation of the carrier binding sites E.g.: glucose is transported into the cells from the blood stream via GLUTs Copyright © 2024 Dr. Abdul-Sater Membrane Transport: assisted membrane transport Copyright © 2024 Dr. Abdul-Sater Membrane Transport: assisted membrane transport transport maximum Which characteristic does this show? Comparison of carrier-mediated transport and simple diffusion down a concentration gradient (Remember that carrier-mediated transport is characterized by three important parameters, including competition) Copyright © 2024 Dr. Abdul-Sater Lecture 8: Learning Objectives By the end of today’s lecture, you should be able to: Understand what primary active transport is Learn how the Na+–K+ ATPase pump works Explain secondary active transport Copyright © 2024 Dr. Abdul-Sater Membrane Transport: assisted membrane transport Carrier-Mediated Transport - Two forms: Active or Passive Transport Active transport: Also requires a carrier protein Expends energy Transfer its passenger “uphill” against a concentration gradient Think of a car on a hill! Moving downhill vs uphill Copyright © 2024 Dr. Abdul-Sater Membrane Transport: assisted membrane transport Primary Active Transport: Energy (ATP) is directly required to move a substance against its concentration gradient Carrier’s binding sites have a greater affinity for the passenger ion on the low-concentration side where the ion is picked up and a lower affinity on the high-concentration side where the ion is dropped off Copyright © 2024 Dr. Abdul-Sater Membrane Transport: assisted membrane transport Primary Active Transport: These carriers are often called pumps (Act as enzymes with ATPase activity) Two types that always transport ions: single type of passenger (i.e., H+ pump or Ca2+ pump) Na+ – K+ pump involves the transfer of two different substances either simultaneously in the same direction or sequentially in opposite directions Copyright © 2024 Dr. Abdul-Sater Membrane Transport: Na+–K+ ATPase pump (Na+–K+ pump) Copyright © 2024 Dr. Abdul-Sater Membrane Transport: assisted membrane transport A single nerve cell membrane contains ~ 1 million Na+–K+ pumps capable of transporting ~200 million ions per second!! Establishes Na+& K+ concentration gradients across plasma membrane Also indirectly serves as the energy source for secondary active transport Copyright © 2024 Dr. Abdul-Sater Membrane Transport: assisted membrane transport Secondary Active Transport: port. This carrier plays an important role in main- Driving ion Transported Driving ion Transported taining the appropriate pH inside the cells (a fluid in high solute in low in high solute in high Energy is required in the entire becomes more acidic as its H1 concentration rises). concentration concentration concentration concentration process but is NOT directly Let us examine Na1 and glucose symport in more detail as an example of secondary active required to run the pump (NO transport. Unlike most body cells, the intestinal ATP is used directly by pump) and kidney cells actively transport glucose by moving it uphill from low to high concentration. The intestinal cells transport this nutrient from Uses “secondhand” energy stored the intestinal lumen into the blood, concentrating it there, until none is left in the lumen to be+lost in in the form of an ion (e.g. Na ) the feces. The kidney cells save this nutrient for the concentration gradient to move the body by transporting it out of the fluid that is to Driving ion Transported Driving ion Transported become urine, moving it against a concentration cotransported molecule uphill gradient into the blood. The symport carriers that in low concentration solute in high concentration in low concentration solute in low concentration transport glucose against its concentration gradi- (a) Symport (b) Antiport ent from the lumen in the intestine and kidneys are distinct from the glucose facilitated-diffusion ❙ Figure 3-17 Secondary active transport. With secondary active transport, an ion concentration carriers that transport glucose down its concen- gradient (established by primary active transport) is used as the energy source to transport a solute tration gradient into most cells. against its concentration gradient. (Usually the driving ion is Na1, whose concentration gradient is es- tablished by the Na1–K1 pump.) Note that for convenience in using arrows to depict the direction in Here, we focus specifically on the symport car- which the carrier moves the transported solute and driving ion, the carrier is shown as being open to rier that cotransports Na1 and glucose in intestinal both sides of the membrane at the same time, which is never the case in reality. (a) In symport, the epithelial cells. This carrier, known as the sodium transported solute moves in the same direction as the gradient of the driving ion. (b) In antiport, the and glucose cotransporter or SGLT, is located in Copyright © 2024 Dr. Abdul-Sater transported solute moves in the direction opposite from the gradient of the driving ion. Membrane Transport: assisted membrane transport Secondary Active Transport: Two Types: port. This carrier plays an important role in main- Driving ion Transported Driving ion Transported taining the appropriate pH inside the cells (a fluid symport (also called becomes more acidic as its H1 concentration rises). in high concentration solute in low concentration in high concentration solute in high concentration cotransport), the solute and Na Let us examine Na1 and glucose symport +in more detail as an example of secondary active move through the membrane in transport. Unlike most body cells, the intestinal the same direction and kidney cells actively transport glucose by moving it uphill from low to high concentration. The intestinal cells transport this nutrient from antiport (also known as the intestinal lumen into the blood, concentrating counter- transport), the solute it there, until none is left in the lumen to be lost in the feces. The kidney cells save this nutrient for the and Na move through the + by transporting it out of the fluid that is to body Driving ion Transported Driving ion Transported become urine, moving it against a concentration membrane in opposite directions gradient into the blood. The symport carriers that in low concentration solute in high concentration in low concentration solute in low concentration transport glucose against its concentration gradi- (a) Symport (b) Antiport ent from the lumen in the intestine and kidneys are distinct from the glucose facilitated-diffusion ❙ Figure 3-17 Secondary active transport. With secondary active transport, an ion concentration carriers that transport glucose down its concen- gradient (established by primary active transport) is used as the energy source to transport a solute e.g. Movement of glucose against concentration tration gradient into most cells. gradient in intestinal and against its concentration gradient. (Usually the driving ion is Na , whose concentration gradient is es- tablished by the Na –K pump.) Note that for convenience in using arrows to depict the direction in 1 Here, we focus specifically on the symport car- 1 1 kidney cells. which the carrier moves the transported solute and driving ion, the carrier is shown as being open to rier that cotransports Na1 and glucose in intestinal both sides of the membrane at the same time, which is never the case in reality. (a) In symport, the Copyright © 2024 Dr. Abdul-Sater epithelial cells. This carrier, known as the sodium  Membrane Transport: assisted membrane transport Secondary Active Transport Primary Active Transport Facilitated diffusion Copyright © 2024 Dr. Abdul-Sater Lecture 9: Learning Objectives By the end of today’s lecture, you should be able to: Understand the various types of vesicular transport Learn the difference between the three forms of endocytosis Explain what exocytosis is and the importance of the balance between endocytosis and exocytosis Copyright © 2024 Dr. Abdul-Sater Membrane Transport: assisted membrane transport Vesicular Transport: For large polar molecules (e.g. protein hormones secreted by endocrine cells) and multi-molecular materials (e.g. bacteria ingested by white blood cells) to enter and leave the cell Requires energy expenditure by the cell Active mechanism of transport This energy is needed to accomplish vesicle formation and movement within the cell Copyright © 2024 Dr. Abdul-Sater Membrane Transport: assisted membrane transport Vesicular Transport: Two forms of active transport: Endocytosis: three forms depending on the material internalized. } Pinocytosis Fuses with lysosome (rare instances bypasses receptor-mediated endocytosis lysosome exocytosis from other phagocytosis end) Exocytosis Copyright © 2024 Dr. Abdul-Sater  Membrane Transport: Endocytosis pinocytosis (nonselective uptake of a sample of ECF) = “cell drinking” Macropinocytosis = large gulps of fluid (This is how dendritic cells take up foreign material to activate the immune system) Copyright © 2024 Dr. Abdul-Sater Membrane Transport: Endocytosis receptor-mediated endocytosis (selective uptake of a large molecule) e.g. insulin, iron, vit. B12 uptake BUT so does Flu, coronaviruses and HIV!! Copyright © 2024 Dr. Abdul-Sater Membrane Transport: Endocytosis phagocytosis (selective uptake of a multimolecular particle) = “cell eating” Unlike pinocytosis and receptor mediated endocytosis, only certain specialized cells can perform phagocytosis ➡ Phagocytes In immune responses, phagocytosis can be enhanced by receptors binding coated pathogens Copyright © 2024 Dr. Abdul-Sater Membrane Transport: Exocytosis Almost the reverse of endocytosis (NO fusion with lysosomes) Two purposes: Secretion of large polar molecules (i.e., hormones or enzymes) Addition of components to membrane (i.e., channels or receptors) Copyright © 2024 Dr. Abdul-Sater Membrane Transport: Exocytosis Exocytosis and secretory vesicles Docking Marker on vesicle docking-marker acceptor on plasma membrane (v-SNARE t-SNARE) “Lock-and-key” Copyright © 2024 Dr. Abdul-Sater Membrane Transport Balance of Endocytosis and Exocytosis Rate of processes are regulated to maintain a constant membrane surface area and cell volume (>100% of plasma membrane can be used in an hour to wrap internalized vesicles!!!) Membrane is constantly restored, retrieved recycled Cells are differentially selective in what enters and leaves Copyright © 2024 Dr. Abdul-Sater Membrane Methods Transport : Summary of Membrane Transport and Their Characteristics ❚ TABLE 3-2 Energy Requirements and Method of Transport Substances Involved Force Producing Movement Limit to Transport Simple Diffusion Diffusion through lipid Nonpolar molecules of any Passive; molecules move down Continues until gradient is bilayer size (e.g., O2, CO2, fatty concentration gradient (from high abolished (dynamic equilibrium acids) to low concentration) with no net diffusion) Diffusion through Specific small ions (e.g., Passive; ions move down Continues until there is no net protein channel Na1, K1, Ca21, Cl2) electrochemical gradient through movement and dynamic open channels (from high to low equilibrium is established concentration and by attraction of ion to area of opposite charge) Osmosis Water only Passive; water moves down its own Continues until concentration concentration gradient (to area of difference is abolished or until lower water concentration—that is, stopped by opposing higher solute concentration) hydrostatic pressure or until cell is destroyed Carrier-Mediated Transport Facilitated diffusion Specific polar molecules for Passive; molecules move down Displays a transport maximum which carrier is available concentration gradient (from high (Tm); carrier can become (e.g., glucose) to low concentration) saturated Primary active Specific cations for which Active; ions move against Displays a transport maximum; transport carriers are available (e.g., concentration gradient (from low to carrier can become saturated Na1, K1, H1, Ca21) high concentration); requires ATP Secondary active Specific polar molecules and Active; substance moves against Displays a transport maximum; transport (symport or ions for which coupled concentration gradient (from low to coupled transport carrier can antiport) transport carriers are high concentration); driven directly become saturated available (e.g., glucose, by ion gradient (usually Na1) amino acids for symport; established by ATP-requiring some ions for antiport) primary pump. In symport, cotransported molecule and driving ion move in same direction; in antiport, transported solute and driving ion move in opposite directions Vesicular Transport Copyright © 2024 Dr. Abdul-Sater Endocytosis  Secondary active Active; substance moves against Specific polar molecules and Displays a transport maximum; transport (symport or concentration gradient (from low to ions for which coupled coupled transport carrier can antiport) high concentration); driven directly transport carriers are become saturated Membrane Methods Transport: Summary by ion gradient (usually Na1) available (e.g., glucose, amino acids for symport; established by ATP-requiring some ions for antiport) primary pump. In symport, ❚ TABLE 3-2 of Membrane Transport cotransported and Theirmolecule Characteristics and driving ion move in same direction; in antiport,Requirements Energy transported solute andand Method of Transport Substances Involved drivingProducing Force ion move inMovement opposite Limit to Transport directions Simple Diffusion Vesicular Transport Diffusion through lipid Nonpolar molecules of any Passive; molecules move down Continues until gradient is Endocytosis bilayer size (e.g., O2, CO2, fatty concentration gradient (from high abolished (dynamic equilibrium Pinocytosis Small volume of ECF fluid; acids) Active; to plasma membrane dips low concentration) Control with poorly no net understood diffusion) also important in membrane inward and pinches off at surface, Diffusion through Specific recyclingsmall ions (e.g., Passive; forming ions move down internalized vesicle Continues until there is no net protein channel Na1, K1, Ca21, Cl2) electrochemical gradient through movement and dynamic Receptor-mediated Specific large polar molecule Active; open plasma (from channels membrane high todips low Necessitates equilibrium is binding to specific established endocytosis (e.g., protein) inward and pinches concentration and byoff at surface, attraction of receptor on membrane surface forming ion internalized to area vesicle of opposite charge) Phagocytosis Osmosis Multimolecular Water only particles Active; cell Passive; extends water movespseudopods down its own Necessitates Continues untilbinding to specific concentration (e.g., bacteria and cellular that surround gradient concentration particle, (to forming area of receptor on difference membraneorsurface is abolished until debris) internalized lower vesicle water concentration—that is, stopped by opposing higher solute concentration) 21 hydrostatic pressure or until cell Exocytosis Secretory products (e.g., Active; increase in cytosolic Ca Secretion triggered by spe- is destroyed hormones and enzymes) induces fusion of secretory vesicle cific neural or hormonal stimuli; Carrier-Mediated Transport as well as large molecules with plasma membrane; vesicle other controls involved in trans- that pass through cell intact; opens up and releases contents to cellular traffic and membrane Facilitated diffusion Specific polar molecules for Passive; molecules move down Displays a transport maximum also important in membrane outside recycling not known which carrier is available concentration gradient (from high (Tm); carrier can become recycling (e.g., glucose) to low concentration) saturated Primary active Specific cations for which Active; ions move against Displays a transport maximum; transport 78 CHAPTER 3 carriers are available (e.g., concentration gradient (from lowUnless to otherwise carrier noted, all can contentbecome on this page issaturated © Cengage Learning. Na1, K1, H1, Ca21) high concentration); requires ATP Secondary active Specific polar molecules and Active; substance moves against Displays a transport maximum; Copyright 2016 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part. Due to electronic rights, some third party content may be suppressed from the eBook and/or eChapter(s). Editorial review has deemed that any suppressed content does not materially affect the overall learning experience. Cengage Learning reserves the right to remove additional content at any time if subsequent rights restrictions require it. transport (symport or ions for which coupled concentration gradient (from low to coupled transport carrier can antiport) transport carriers are high concentration); driven directly become saturated available (e.g., glucose, by ion gradient (usually Na1) amino acids for symport; established by ATP-requiring some ions for antiport) primary pump. In symport, cotransported molecule and driving ion move in same direction; in antiport, transported solute and driving ion move in opposite directions Vesicular Transport Copyright © 2024 Dr. Abdul-Sater Endocytosis