3.1 BIOLOGICAL MEMBRANES 3.1.1 Properties of Cell Membranes • Separates living cell from its nonliving surroundings. • 8 nm thick. • Selectively permeable - allows some substances to cross more easily than others. 4.1.2 Fluid Mosaic Model • Singer and Nicolson (1972) - plasma membrane is a mosaic of proteins dispersed within lipid bilayer‚ with only bilayer‚ the hydrophilic regions exposed to water. Hydrophilic region of protein Phospholipid bilayer Hydrophobic region of protein
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1 Experiment Membrane Transport Objectives ► Referring to energy‚ what two ways can substances enter a cell? What is active transport? What is passive transport? How is osmosis related to diffusion? How can we demonstrate active transport? How can we demonstrate Brownian movement? How can we demonstrate diffusion (2 ways)? How can we demonstrate osmosis (3 ways)? In terms of relationships between substances‚ how can we define “hypertonic”‚ “isotonic”‚ and “hypotonic”? What is the relationship
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BIOL 2010 ANATOMY AND PHYSIOLOGY I Chapter 4: TISSUES AND MEMBRANES Outline of Notes I. Introduction. A. General: Cells are highly specialized and interdependent on one another. Groups of similar cells performing similar functions are called Tissues The study of tissues is called Histology. Organs are made of tissues. A detailed understanding of tissues will greatly help your understanding of organs and organ systems later in this course. Tissues are classified into 4 main types:
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Biological Membranes Lipid Membranes • Receptors‚ detecting the signals from outside: Light Odorant Taste Chemicals A Hormones Neurotransmitters Drugs • Channels‚ gates and pumps • Electric/chemical potential Neurophysiology Energy • Energy transduction: Photosynthesis Oxidative phosphorylation • • • • • • Structure Function Composition Physicochemical properties Self-assembly Molecular models highly selective permeability barrier Internal membranes for organelles Bilayer Permeability
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Martina Oganesyan Title of investigation: The effect of solute concentration on osmosis in potatoes. Research question: What is the solute concentration of a potato? Hypothesis: Osmosis is the movement of water across the membrane from an area of high concentration to an area of low concentration. The osmosis continues until the solute concentrations are equal in both areas. In this experiment‚ we put pieces of potatoes into test tubes with sugar solutions of different concentrations and leave
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Lecture: Plasma Membrane and Transport I. Structure of the Plasma Membrane A. plasma membrane - the surface encapsulating a cell B. Fluid Mosaic Model 1. bilayer of phospholipids a. hydrophilic heads - P04 end "water" "loving" attracted to water on inner/outer parts of cell b. hydrophobic tails - fatty acids "water" "fearing" attracted to each other on inside of bilayer c
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is an empirical relationship that relates the absorption of light to the properties of the material through which the light is travelling. In turn‚ absorbance is proportional to concentration and the higher the concentration‚ the higher the absorbance. This experiment incorporated Beer’s Law and is focused on determining the stress that various alcohols have on biological membranes. Using five solutions of differing alcohol concentration for each of the three alcohols; methanol‚ ethanol‚ and 1-propanol
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Transport Across The Plasma Membrane Intracellular Fluid (ICF) – The two thirds of your body fluid contained inside body cells. (Intra = within). The cytosol of the cell. Extracellular Fluid (ECF) – Fluid outside the body cells. (extra = outside). Interstitial Fluid – The ECF in tiny spaces between cells (inter = between). Plasma- the ECF in blood vessels. Lymph- The ECF in lymphatic vessels. Solute – Any material dissolved in fluid. Solvent- The fluid a Solute is dissolved in. Concentration
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Practical 2.1- The Effect of Temperature on Membranes Objective To investigate the effect of temperature on membrane structure Introduction Beetroot Pigments Beetroots contain Betalains which are the red pigments present in the cell vacuole. Betalains are soluble in water and they contain nitrogen. Betalains extracted from beetroot is commonly used as food dye because it is not known to cause any allergic reactions. Beetroot Picture taken from http://tipdeck/how-to-cook-beet-root Structure
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BioLab3 Cell Membranes Lab Report Student Name: I. Diffusion Define the following terms. Solvent Solute Solution. Diffusion Concentration gradient Dynamic equilibrium EXERCISE 1 – Factors influencing rate of diffusion Predict how molecule size and temperature will affect the outcome of this experiment. Record the data from the information in the lab. Potassium Permanganate R.T. Methylene Blue R.T. Time (min) Total Diameter
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