DOCSLIB.ORG

Hyperosmotic Hyposmotic Isosmotic Hypertonic Isotonic Hypotonic

Total Page：16

File Type：pdf, Size：1020Kb

Download full-text PDF Read full-text
Hyperosmotic Hyposmotic Isosmotic Hypertonic Isotonic Hypotonic Taking care of business Go to this page and enter room SJ123: http://tinyurl.com/PhysClicker Take 2 minutes to complete this survey: http://tinyurl.com/PhysDis Online quiz this weekend: Released Thursday night or early Friday morning and will be due Monday morning at 9am. Lab next week: We will meet in the first floor lobby of the Tech building (right next to Science Complex) for lab next week. We’re going to try to apply some of the stuff we’ve learned so far in a simulated clinical environment. It’ll be cool. Online discussions: Reminder-please post ANY questions you might have about anything related to the class to the weekly discussion. Happy to help! Homeostasis Recap Membrane Dynamics Chapter 5 Super duper Super duper hyper osmotic hyper osmotic What will happen to cell? A. Swell up B. Shrivel C. Stay the same D. I don’t know Our patient for the day https://www.youtube.com/watch?v=w3uWg4KjX4Y Name: Matilda Age: 78 In hospital for severe dehydration Staff puts her on IV of pure water Soon after IV: Severe fatigue Dizzy Yellow eyes Iced tea analogy On board Describing how concentrated a solution is: Molarity= moles solute / Liters solution Osmolarity= osmoles solute / Liters solution 1) NaCl dissociates into Na+ and Cl- 1 mole of NaCl = 2 osmoles of NaCl 2) Glucose does not dissociate in water Diffusion, osmosis, concentration.... WHO CARES?!?!? Hippotonic (hypotonic) solution makes cell swell like a hippo Table 5.3 Tonicity of Solutions Tonicity describes the volume change of a cell Differences between osmolarity and tonicity Differences between osmolarity and tonicity •Osmolarity = concentration of particles in a solution. •Tonicity has no units. It just describes whether cell gained/lost water. •Osmolarity is used to compare any two solutions, tonicity only can compare a solution to a cell •Osmolarity alone does not tell you what happens to a cell placed in a solution (as we’ll see). Table 5.2 Comparing Osmolarities Osmolarity comparisons hypo=lower Salt becomes two ions/ particles in water. Glucose iso=same doesn’t hyper=higher Tonicity comparisons Hippotonic (hypotonic) solution makes cell swell like a hippo Name: Matilda Age: 78 In hospital for severe dehydration Staff puts her on IV of pure water What do you think caused this? 1.) Think for 1 minute 2.) Pair up 3.) Share your ideas What do you think caused this? Hyptonic Low osmolarity 1.) Think for 1 minute 2.) Pair up Low3.) ShareNa+ osmolarityyour ideas Figure 5.1a ESSENTIALS – Body Fluid Compartments Sidenote: other cells in body need proper salt, water balance The body fluids are in two compartments: the extracellular fluid (ECF) and intracellular fluid (ICF). The ECF and ICF are in osmotic equilibrium but have very different chemical composition. Intracellular fluid is 2/3 of the KEY total body water volume. Material moving into and out of the ICF Intracellular fluid must cross the cell membrane. Interstitial fluid Plasma Extracellular fluid includes all fluid outside the cells. The ECF is 1/3 of the body fluid volume. The ECF consists of: • Interstitial fluid (IF), which lies between the circulatory system and the cells, is 75% of the ECF volume. • Plasma, the liquid matrix of blood, is 25% of the ECF volume. Substances moving between the plasma and interstitial fluid must cross the leaky exchange epithelium of the capillary wall. Following slides have material that will be addressed with discussion topics questions in class worksheet. Super duper Super duper hyper osmotic hyper osmotic What will happen to cell? A. Swell up B. Shrivel C. Stay the same D. I don’t know Part 2: Tonicity depends on what KINDS of solutes are in solution, not just osmolarity Can solutes in the solution pass through membrane or not? Super duper hyper osmotic WillDoes water the soluteflow into penetrate or out of the the cell? cell membrane? Super duper hyper osmotic Figure 5.3 The relationship between osmolarity and tonicity If you’re given the osmolarity, what could tonicity possibly be? * OSMOLARITY TONICITY Hyposmotic Isosmotic Hyperosmotic Hypotonic Isotonic Hypertonic *Assume all intracellular solutes can’t penetrate cell membrane Figure 5.3 The relationship between osmolarity and tonicity If you’re given the osmolarity, what could tonicity possibly be?* OSMOLARITY TONICITY Hyposmotic Isosmotic Hyperosmotic Hypotonic Isotonic Hypertonic *Assume all intracellular solutes can’t penetrate cell membrane Figure 5.3 The relationship between osmolarity and tonicity If you’re given the osmolarity, what could tonicity possibly be? * OSMOLARITY TONICITY Hyposmotic Isosmotic Hyperosmotic Hypotonic Isotonic Hypertonic *Assume all intracellular solutes can’t penetrate cell membrane Figure 5.3 The relationship between osmolarity and tonicity If you’re given the osmolarity, what could tonicity possibly be? * OSMOLARITY TONICITY Hyposmotic Isosmotic Hyperosmotic Hypotonic Isotonic Hypertonic *Assume all intracellular solutes can’t penetrate cell membrane Steps to determine tonicity of a solution compared to a cell 1.) Assume all particles inside the cell cannot cross cell membrane. They’re stuck. 2.) Compare solute concentrations for each particle inside the cell vs. outside 3.) Allow any particles that are outside the cell to diffuse into the cell to equalize their own concentration inside vs. outside the cell. 4.) Compare solute concentrations again inside vs. outside the cell. 5.) Determine where water would go based on osmosis (it goes towards higher solute concentration) Name: Matilda Age: 78 In hospital for severe dehydration Staff puts her on IV of water Why might this IV solution cause Matilda serious problems? Severe fatigue Dizzy Yellow eyes Rapidly increasing heartrate Table 5.5 Intravenous Solutions Common IV solution properties as compared to a normal human cell End material that was covered by discussion questions in class Simple Diffusion is what we’ve been talking about so far. Simple Diffusion is when particles, gases, whatever passes directly through the cell membrane on its own, without any assistance Figure 5.7 Fick s law of diffusion ’ 5 factors affect the rate of diffusion 4 1 Extracellular fluid Membrane Lipid Molecular Concentration surface area solubility size outside cell 2 Factors affecting rate of diffusion through a cell membrane: • Lipid solubility 5 Concentration • Molecular size 3 gradient • Concentration gradient • Membrane surface area Composition • Composition of lipid layer of lipid layer Intracellular fluid Concentration inside cell Fick’s Law of Diffusion Membrane Permeability lipid solubility Rate of diffusion ∝ surface area × concentration gradient × membrane permeability Membrane permeability ∝ molecular size Changing the composition of the lipid layer can increase or decrease membrane permeability. For next time: Think about how YOU would have treated Matilda differently than the nurses did. Name: Megan Age: 3 Chronic Resp. Infections Thick mucus in airways Severe difficulty breathing Part II: Transport Processes Across the Membrane via Proteins The cell membrane is packed with proteins that serve many functions Transport The cell membrane is packed with proteins that serve many functions Transport Signaling The cell membrane is packed with proteins that serve many functions Transport Signaling Catalysis The cell membrane is packed with proteins that serve many functions Transport Signaling Catalysis Structural The cell membrane is packed with proteins that serve many functions Transport Channel protein transporters are like doors Channel Proteins Open Free Passage E.g. Aquaporin Transports Water Channel protein transporters are like doors Channel Proteins Open Closed X Free Key Passage Needed Transport “Gated” Channels Chemically Gated Channels Require Molecule Binding Voltage-Gated Channels Respond to Change in Charge Across Cell Membrane So, channel proteins, either the open or gated kind, are like doors Carrier Proteins Change Confirmation to Pass Solute Carrier Proteins Have a Variety of Unique Properties •Used to carry large and/or ionic substances •Never make continuous passage to ECF •Require conformational change Figure 5.12 Facilitated diffusion by means of a carrier protein Carrier Proteins Change Confirmation to Pass Solutes Intro to Physio Closed gate Extracellular fluid Intracellular fluid Pacific Atlantic Passage Gate closed MotivationOcean and Molecule Ocean open to Relevance one side to be Carrier transported Membrane How I learn science Transition Pacific Atlantic state with Ocean Some Course Deets Ocean both gates closed Real Intro to Physio: Homeostasis Passage NegativePacific Feedback Atlantic open to Gate closed Ocean Ocean other side Positive Feedback Homeostasis v. Equilibrium Figure 5.13 Facilitated diffusion of glucose into cells CarrierLarge andProteins Polar Change Molecules Confirmation Use Carriers to Pass Solutes Intro to Physio To Passively Diffuse Across Membrane High glucose [Glucose] = high[Glucose]out Motivation and concentration out Relevance [Glucose]in [Glucose]in GLUT stays low ATP How I learn science ADP G-6-P Glycogen Some Course DeetsLow glucose concentration Glycolysis Real Intro to Physio: Homeostasis Facilitated diffusion brings glucose Diffusion reaches equilibrium when the Conversion of imported glucose into into the cell down its concentration glucose concentrations inside and glucose 6-phosphate (G-6-P) keeps Negativegradient. Feedback outside the cell are equal. intracellular glucose concentrations low so that diffusion never reaches equilibrium. Positive Feedback Passive, facilitated diffusion uses no energy Homeostasis v. Equilibrium TRANSPORT AGAINST CONCENTRATION GRADIENT REQUIRES ENERGY “Active Transport” Uses Energy to Move Solutes Against Gradient “Active Transport” Uses Energy to Move Solutes Against Gradient “Active Transport” Uses Energy to Move Solutes Against Gradient “Active Transport” Uses Energy to Move Solutes Against Gradient Fun Fact! ~30% of our energy goes to powering the Na+/K+ pump! .
Load more

Recommended publications
  • Osmosis and Osmoregulation Robert Alpern, M.D
    Osmosis and Osmoregulation Robert Alpern, M.D. Southwestern Medical School Water Transport Across Semipermeable Membranes • In a dilute solution, ∆ Τ∆ Jv = Lp ( P - R CS ) • Jv - volume or water flux • Lp - hydraulic conductivity or permeability • ∆P - hydrostatic pressure gradient • R - gas constant • T - absolute temperature (Kelvin) • ∆Cs - solute concentration gradient Osmotic Pressure • If Jv = 0, then ∆ ∆ P = RT Cs van’t Hoff equation ∆Π ∆ = RT Cs Osmotic pressure • ∆Π is not a pressure, but is an expression of a difference in water concentration across a membrane. Osmolality ∆Π Σ ∆ • = RT Cs • Osmolarity - solute particles/liter of water • Osmolality - solute particles/kg of water Σ Osmolality = asCs • Colligative property Pathways for Water Movement • Solubility-diffusion across lipid bilayers • Water pores or channels Concept of Effective Osmoles • Effective osmoles pull water. • Ineffective osmoles are membrane permeant, and do not pull water • Reflection coefficient (σ) - an index of the effectiveness of a solute in generating an osmotic driving force. ∆Π Σ σ ∆ = RT s Cs • Tonicity - the concentration of effective solutes; the ability of a solution to pull water across a biologic membrane. • Example: Ethanol can accumulate in body fluids at sufficiently high concentrations to increase osmolality by 1/3, but it does not cause water movement. Components of Extracellular Fluid Osmolality • The composition of the extracellular fluid is assessed by measuring plasma or serum composition. • Plasma osmolality ~ 290 mOsm/l Na salts 2 x 140 mOsm/l Glucose 5 mOsm/l Urea 5 mOsm/l • Therefore, clinically, physicians frequently refer to the plasma (or serum) Na concentration as an index of extracellular fluid osmolality and tonicity.
    [Show full text]
  • Growth Rate and Turgor Pressure
    Plant Physiol. (1974) 54, 863-869 Growth Rate and Turgor Pressure AUXIN EFFECT STUDIED WITH AN AUTOMATED APPARATUS FOR SINGLE COLEOPTILES' Received for publication March 22, 1974 and in revised form July 5, 1974 PAUL B. GREEN AND W. RAYMOND CUMMINS2 Department of Biological Sciences, Stanford University, Stanford, California 94305 Downloaded from https://academic.oup.com/plphys/article/54/6/863/6074159 by guest on 28 September 2021 ABSTRACT scripts indicate that the value is characteristic of steady rate, as distinguished from values accompanying transients between Because turgor pressure is regarded as the driving force for steady rates. cell extension, any general theory of plant growth requires In equation 1 increasing pressure inevitably raises rate. Since quantitative information on the relationship between steady auxin has not been found to raise the osmotic concentration of irreversible growth rate and turgor pressure. To investigate responding excised tissue (21), it appears not to act via changes contrasting views of this relation an automated apparatus was in the P term. It could raise steady rate by either raising m, constructed which perfused both the outer and inner epidermis (Fig. la) or lowering Y, (Fig. lb), or both could change. If r, of a single coleoptile while its growth rate was continuously is a linear function of (P - Y) as in equation 1 and Figure 1, recorded. Turgor was altered abruptly by perfusing with solu- the mode of action should be easily ascertained. If the true re- tions of varying tonicity. With specially grown rye coleoptiles lation were concave upward, the mode of action of auxin action the half-time of the osmo-elastic response was reduced to 2 (curve shifting versus curve steepening) would be less obvious minutes or less.
    [Show full text]
  • Osmolarity and Tonicity: an Inquiry Laboratory Using Plant Material
    Tested Studies for Laboratory Teaching Proceedings of the Association for Biology Laboratory Education Vol. 32, 135-150, 2011 Osmolarity and Tonicity: An Inquiry Laboratory Using Plant Material Dee U. Silverthorn Integrative Biology, One University Station C0930, University of Texas, Austin TX 78712 ([email protected]) The difference between osmolarity and tonicity is a difficult concept for students to understand and often for fac- ulty to teach. We adapted techniques from the traditional potato-plug laboratory to create an inquiry laboratory that demonstrates the principles of osmolarity and tonicity. Students design two experiments: first, they must try to determine the internal osmolarity of their plant material, and second, they test whether a particular solute is a penetrating solute for plant cells. The inquiry level can be adjusted by the instructor. Keywords: osmolarity, osmosis, tonicity, solutions, plant cells, sugar transport, urea Introduction The difference between osmolarity and tonicity is a dif- This laboratory exercise teaches students how penetrating ficult concept for students to grasp. The coverage of tonicity solutes affect tonicity and challenges their understanding by in most introductory biology textbooks is perfunctory at best asking them to design an experiment to determine whether and sometimes inaccurate or misleading. Yet a clear under- a solute (sucrose, glucose, or urea) is penetrating for plant standing of the difference between the osmolarity of a so- cells. This information is not something they can easily look lution and its tonicity is essential for pre-health-professions up on the web, so they must make predictions based on their students because tonicity is the basis for the appropriate understanding of tonicity.
    [Show full text]
  • Topic 2: Cells and Cell Processes Cells: Cell Theory 1. 2. 3. **There Are 2 Exceptions to the Cell Theory 1. the First Cell
    Topic 2: Cells and Cell Processes Cells: Cell Theory 1. 2. 3. **There are 2 exceptions to the Cell Theory 1. The first cell could not come from a previous existing cell 2. Viruses are not made up of cells but they do contain genetic material. Viruses reproduce inside another cell, called the cell. Organelles: Specialized subunits within the cell that has a specific function Cells can be separated into 2 broad categories o o **The average person is made up of approximately 100 trillion cells and 200 different eukaryotic cell types** Prokaryotic Cells Eukaryotic Cells Both Theory of Endosymbiosis Eukaryotic cells containing organelles (like mitochondria and chloroplasts) evolved when free-living prokaryotes took up permanent residence inside other larger prokaryotic cells (about 2 billion years ago) This became the origin of complex eukaryotic cells leading to the evolution of all multi-celled organisms Organelle Function Cytoskeleton Proteins that support and shape the cell Microtubules Make up cilia, flagella and spindle fibers Microfilaments Made up of actin and help support the shape of the cell Cytoplasm Fluid like portion Located between the and the__________________ Holds the organelles in place Nucleus Stores and protects the genetics information (DNA) Also contains the __________________________ Nucleolus Responsible for the production of _______________________________ Mitochondria “Powerhouse” of the cell Supplies __________________________ to the cell through the process of _____________________________________
    [Show full text]
  • Cell Membrane & Tonicity Worksheet
    NAME__________ ANSWER KEY ___________________ DATE_________________ PERIOD_________ Cell Membrane & Tonicity Worksheet Composition of the Cell Membrane & Functions The cell membrane is also called the PLASMA membrane and is made of a phospholipid SKETCH AND LABEL a phospholipid coloring BI-LAYER. The phospholipids have a hydrophilic (water attracting) HEADS and two the heads red and the hydrophobic (water repelling) TAILS. The head of a phospholipid is made of an alcohol and tails blue. GLYCEROL group, while the tails are chains of FATTY ACIDS. Phospholipids can move SIDEWAYS and allow water and other NON-POLAR molecules to pass through into or out of the cell. This is known as simple PASSIVE TRANSPORT because it does not require ENERGY and the water or molecules are moving WITH the concentration gradient. Another type of lipid in the cell membrane is CHOLESTEROL that makes the membrane more fluid. Embedded in the phospholipid bilayer are PROTEINS that also aid in diffusion and in cell recognition. Proteins called INTEGRAL proteins go all the way through the bilayer, while PERIPHERAL proteins are only on one side. Large molecules like PROTEINS or carbohydrates use proteins to help move across cell membranes. Some of the membrane proteins have carbohydrate PARTS attached to help cells in recognize each other and certain molecules. List 4 functions of the cell or plasma membrane: a. CELL SIGNALING b. SELECTIVE TRANSPORT c. EXCRETION OF WASTES d. STRUCTURAL SUPPORT Correctly color code and identify the name for each part of the cell membrane. Letter Name/Color Letter Name/Color __ A ___ Phospholipid bilayer (no color) __ H ___ Peripheral protein (red) __ B ___ Integral protein (pink) __ I ____ Cholesterol (blue) __ F ___ Fatty acid tails (orange) __ C___ Glycoprotein (green) __ G ___ Phosphate heads (yellow) __ E ___ Glycolipids (purple) Match the cell membrane structure or its function with the correct letter from the cell membrane diagram.
    [Show full text]
  • Tonicity of Solutions
    TONICITY OF SOLUTIONS By: Lindsay Seely Grade Level • 10th, Variation of Unit 1, Activity 5 in LCC • GLEs SI 1, 9, 10; LS 5 Materials 1. Elodea or red onion 2. Distilled water (hypotonic) 3. 0.9% Salt solution (isotonic) 4. 15% Salt solution (hypertonic) 5. Pipettes 6. Four slides with cover slips, deep well slides or Petri dishes 7. SOAR with 200X lens; use either in Stand-and-view or Invert-and-view configuration with XYZ mechanical stage Procedure I. Discuss cell membrane structure and diffusion. II. Make up solutions – use the formulas given in the LCC, or for smaller amounts: A. For .9% solution, add 0.45 grams of table salt to 50mL of distilled water B. For 15% solution, add 7.5 grams of table salt to 50mL of distilled water III. Perform lab activity (Students will determine the effects of hypertonic, hypotonic, and isotonic solutions on a plant cell and predict in what direction water molecules will move when exposed to solutions) A. Identify safety measures B. Hypothesis: Water will flow into cells when placed in a hypotonic solution; water will flow out of cells when place in hypertonic solution. C. Experiment: 1. Have a control slide of the plant to show students cells using SOAR 2. Provide students with three slides of cell type being examined 3. Use a pipette to drop a different solution type on each slide 4. Wait 15 minutes and observe cells using SOAR D. Analysis: Record observations in words and sketches E. Conclusion: Write observations based on cells in types of solutions and direction of net flow of water References NatGeo Biology: Dynamics of Life 2004 ed.
    [Show full text]
  • Glossary.Pdf
    Glossary Pronunciation Key accessory fruit A fruit, or assemblage of fruits, adaptation Inherited characteristic of an organ- Pronounce in which the fleshy parts are derived largely or ism that enhances its survival and reproduc- a- as in ace entirely from tissues other than the ovary. tion in a specific environment. – Glossary Ј Ј a/ah ash acclimatization (uh-klı¯ -muh-tı¯-za -shun) adaptive immunity A vertebrate-specific Physiological adjustment to a change in an defense that is mediated by B lymphocytes ch chose environmental factor. (B cells) and T lymphocytes (T cells). It e¯ meet acetyl CoA Acetyl coenzyme A; the entry com- exhibits specificity, memory, and self-nonself e/eh bet pound for the citric acid cycle in cellular respi- recognition. Also called acquired immunity. g game ration, formed from a fragment of pyruvate adaptive radiation Period of evolutionary change ı¯ ice attached to a coenzyme. in which groups of organisms form many new i hit acetylcholine (asЈ-uh-til-ko–Ј-le¯n) One of the species whose adaptations allow them to fill dif- ks box most common neurotransmitters; functions by ferent ecological roles in their communities. kw quick binding to receptors and altering the perme- addition rule A rule of probability stating that ng song ability of the postsynaptic membrane to specific the probability of any one of two or more mu- o- robe ions, either depolarizing or hyperpolarizing the tually exclusive events occurring can be deter- membrane. mined by adding their individual probabilities. o ox acid A substance that increases the hydrogen ion adenosine triphosphate See ATP (adenosine oy boy concentration of a solution.
    [Show full text]
  • GLOSSARY Supporting “Processes in the Electrolytic Neuron,”
    Glossary - 1 Date: 4 June 2011 GLOSSARY supporting “Processes in the Electrolytic Neuron,” “Processes in Biological Vision,” “Processes in Biological Hearing” & “Processes in Biological Olfaction” © 2009 James T. Fulton, author www.neuronresearch.net This Glossary is a record of the paradigm shift in the visual sciences cataloged in the accompanying text, “Processes in Biological Vision.” The definitions provided here take precedence over other definitions in the literature. For a broader glossary of many Biological and medical terms (except those introduced here), the reader might look at the Online Medical Dictionary at www.cancerweb.ncl.ac.uk/omd/. • A glossary of the neurosciences appears in Review of Neurosciences, 2nd ed. by Pansky, et. al. (LC call # WL 101 P196r, 1988). • Oyster has also recently (1999) provided an extensive glossary at the rear of his text (LC call # WW 103 O98h, 1999). • Miller & Newman have provided a glossary of terms associated with cerebral visual defects (LC call # WW 140 w223 1998). • Two glossaries covering the human brain are useful and complementary, Nolte & Angevine (LC call WL 17 n798h 2000) and Orrisone (LC call WL 17 o75a 1995). • Hunt provides a table of units for photometric, radiometric and quantal measurements. (LC call # QC 495 H84 1991). • Byrne & Hilbert have provided a broad glossary related to vision (LC call # QC 495 R32 1997) • Millodot’s book is also an asset, Dictionary of Optometry and Visual Science (LC call # WW 13 M656d, 2009) • Shallenberger has provided a specialized dictionary of stereochemical terms (LC call #QD 321 S428, 1982) The term LC refers to the library call provided by the National Institute of Health Library rather than the Library of Congress.
    [Show full text]
  • Osmometric Behavior of Normal Human Erythrocytes
    OSMOMETRIC BEHAVIOR OF NORMAL HUMAN ERYTHROCYTES George M. Guest, Mary Wing J Clin Invest. 1942;21(3):257-262. https://doi.org/10.1172/JCI101297. Research Article Find the latest version: https://jci.me/101297/pdf OSMOMETRIC BEHAVIOR OF NORMAL HUMAN ERYTHROCYTES By GEORGE M. GUEST AND MARY WVING (Front The Childrent's Hospital Research Foiundationt antd the Departmlenit of Pediatrics, College of Medicine, Untiversity of Cincinnzati, Cincinnzati) (Received for publication October 22. 1941) It is generally accepted that when erythrocytes METHOD are suspenided in hypotonic solutions thev first Apparatuis. The modified Van Allen hematocrit tube take up water and swell, and theni at some critical illustrated in Figure 1 contains 8.0 cc. when filled to the tonicity burst and allow hemoglobin to escape. upper mark, and the graduated portion of the stem (100 divisions, numbered by tens) contains 0.02 cc. It is While there are many indications that the permea- necessary that the bulb of the pipette should slope steeply bility of these cells to both salts and water may and smoothly into the stem so that no cells will stick at vary considerably in different conditions (1, 2, 3), the shoulder during centrifugation. For centrifugation of quantitative data on the osmometric behavior of a series of the pipettes, we use the International Centri- are scarce. fuge Type SB, No. 2, with 8-place head and 3-place either normal or abnormal erytlhrocytes trunnion carriers. The pipettes, each sealed with a spring Methods used in clinical studies of the osmotic clip as shown in Figure 1, are placed in 15 cc.
    [Show full text]
  • Cell Membrane & Tonicity Worksheet
    NAME_____________________________ DATE_________________ PERIOD_________ Cell Membrane & Tonicity Worksheet Composition of the Cell Membrane & Functions The cell membrane is also called the _______________ membrane and is made of a SKETCH AND LABEL a phospholipid _____________. The phospholipids have a hydrophilic (water attracting) phospholipid coloring the heads red and the __________ and two hydrophobic (water repelling) ____________. The head of a tails blue. phospholipid is made of an alcohol and __________ group, while the tails are chains of ____________. Phospholipids can move _______________ and allow water and other _________ molecules to pass through into or out of the cell. This is known as simple ____________ because it does not require __________ and the water or molecules are moving __________ the concentration gradient. Another type of lipid in the cell membrane is ______________ that makes the membrane more fluid. Embedded in the phospholipid bilayer are __________ that also aid in diffusion and in cell recognition. Proteins called _____________ proteins go all the way through the bilayer, while ____________ proteins are only on one side. Integral proteins are also called __________ proteins. Large molecules like ___________ or carbohydrates use proteins to help move across cell membranes. Some of the membrane proteins have carbohydrate __________ attached to help cells in recognize each other and certain molecules. List 4 functions of the cell or plasma membrane: a. _________________________________________ b. _________________________________________
    [Show full text]
  • Osmosis, Tonicity, and Concentration
    Lab #5: Osmosis, Tonicity, and Concentration. Background. The internal environment of the human body consists largely of water-based solutions. A large number of different solutes may be dissolved in these solutions. Since movement of materials across cell membranes is heavily influenced by both differences in the concentration of these various materials across the cell membrane and by the permeability of the lipid bilayer to these materials, it is critical Fig 5.1. An example of simple diffusion. Molecules of that we understand how the concentration of a red dye gradually diffuse from areas of higher particular solute is quantified, as well as how concentration to areas of lower concentration until the differences in concentration influence passive concentration of dye is uniform throughout the volume of the solution. membrane transport. membranes (i.e., small uncharged molecules or Diffusion, Osmosis, and Tonicity moderate-sized nonpolar molecules) are transported across cell membranes via simple Simple diffusion . diffusion. For example, the exchange of gases such as O 2 and CO 2 across the plasma membrane Particles in solution are generally free to move occurs through simple diffusion. randomly throughout the volume of the solution. As these particles move about, they randomly Osmosis collide with one another, changing the direction each particle is traveling. Like some other small, uncharged molecules, If there is a difference in the concentration water (H 2O) can pass quite readily through a cell of a particular solute between one region of a membrane, and thus will diffuse across the solution and another, then there is a tendency for membrane along its own concentration gradient the substance to diffuse from where it is more independent of other particles that may be concentrated to where it is less concentrated.
    [Show full text]
  • Central Mechanisms of Osmosensation and Systemic Osmoregulation
    REVIEWS Central mechanisms of osmosensation and systemic osmoregulation Charles W. Bourque Abstract | Systemic osmoregulation is a vital process whereby changes in plasma osmolality, detected by osmoreceptors, modulate ingestive behaviour, sympathetic outflow and renal function to stabilize the tonicity and volume of the extracellular fluid. Furthermore, changes in the central processing of osmosensory signals are likely to affect the hydro-mineral balance and other related aspects of homeostasis, including thermoregulation and cardiovascular balance. Surprisingly little is known about how the brain orchestrates these responses. Here, recent advances in our understanding of the molecular, cellular and network mechanisms that mediate the central control of osmotic homeostasis in mammals are reviewed. osmolality Osmolality Changes in extracellular fluid (ECF) cause changes in ECF osmolality can cause severe neurological A quantitative measure of the water to flow across cell membranes to equilibrate the symptoms in these species owing to the effects of altered total solute concentration in osmolality of the cytoplasm with that of the ECF1. By electrolyte concentrations on neuronal excitability12,13 and a solution expressed in moles altering cell volume and intracellular ionic strength, the physical trauma that can be caused by such condi- per kilogram of solution. large changes in ECF osmolality can affect the physical tions14,15 (BOX 1). In this Review I address the mechanisms Osmolality is not the same 2 as osmolarity, which is the integrity of cells and tissues and the biological activity by which mammals defend against large changes in ECF number of moles of total of life-sustaining macromolecules3. This is a threat that osmolality. Following a brief overview of the processes solutes per litre of solution.
    [Show full text]