Metabolism, The Plasma Membrane, and Transport (Human Physiology) PDF

Chapter 2 Metabolism The Plasma Membrane and Transport 1 Copyright © 2022 by Nelson Education Ltd.  Typical Cell 2 Copyright © 2022 by Nelson Education Ltd.  Mitochondria a. Energy...

Chapter 2 Metabolism The Plasma Membrane and Transport 1 Copyright © 2022 by Nelson Education Ltd.  Typical Cell 2 Copyright © 2022 by Nelson Education Ltd.  Mitochondria a. Energy organelle i. Major site of ATP production ii. Contains enzymes for citric acid cycle and electron transport chain b. Enclosed by a double membrane i. Inner and outer ii. Intermembrane space iii. Matrix 3 Copyright © 2022 by Nelson Education Ltd.  ATP Production Sequence of steps involved in generation of ATP within the cell A. Glycolysis B. Citric acid cycle C. Electron transport chain 4 Copyright © 2022 by Nelson Education Ltd.  An Overview 5 Copyright © 2022 by Nelson Education Ltd.  ATP Yield from One Glucose Molecule 6 Copyright © 2022 by Nelson Education Ltd.  Aerobic vs. Anaerobic metabolism 7 Copyright © 2022 by Nelson Education Ltd. Figure 2-5, p. 28  Plasma Membrane Functions: i. Thin layer of lipids and protein that forms outer boundary of every cell ii. Controls movement of molecules iii. Participates in joining cells iv. Plays a role in the ability of a cell to respond to changes in the cell’s environment 8 Copyright © 2022 by Nelson Education Ltd.  Plasma Membrane Structure Makeup: i. Most abundant molecules are phospholipids a. Polar end b. Nonpolar end ii. Also has small amount of carbohydrates iii. Cholesterol a. Tucked between phospholipid molecules b. Contributes to fluidity and stability of cell membrane 9 Copyright © 2022 by Nelson Education Ltd. Structure and Organization of Phospholipid Molecules in a Lipid Bilayer 10 Copyright © 2022 by Nelson Education Ltd.  Plasma Membrane Structure Functions for membrane proteins: a. Span membrane to form channels across lipid bilayer b. Serve as carrier molecules c. Used as docking-marker acceptors d. Membrane-bound enzymes e. Receptor sites f. Cell adhesion molecules (CAMs) g. Are important in cells’ ability to recognize “self ” and in cell-to-cell interaction 11 Copyright © 2022 by Nelson Education Ltd.  Plasma Membrane Structure Functions of lipid bi-layer: a. Forms basic structure of the membrane b. Forms a barrier to water-soluble substances c. Fluid-mosaic model 12 Copyright © 2022 by Nelson Education Ltd.  Plasma Membrane Structure Functions of membrane carbohydrates: a. Serve as self-identity markers b. Carbohydrate-containing surface markers are also involved in tissue growth 13 Copyright © 2022 by Nelson Education Ltd. 14 Copyright © 2022 by Nelson Education Ltd.  Cell-To-Cell Adhesions A. Bind groups of cells into tissues and package them into organs B. Cells are held together by three different means: 1. Extracellular matrix made up of collagen, elastin, and fibronectin 2. Cell adhesion molecules (CAMS), include cadherins and integrins. 3. Specialized cell junctions, such as, desmosomes, tight junctions, and gap junctions. 15 Copyright © 2022 by Nelson Education Ltd.  ECM 16 Copyright © 2022 by Nelson Education Ltd.  Specialized Cell Junctions Three types of specialized cell junctions A. Desmosomes B. Tight junctions C. Gap junctions 17 Copyright © 2022 by Nelson Education Ltd.  Desmosomes i. Act like “spot rivets” that anchor two closely adjacent cells ii. Found in tissues that are subject to considerable stretching 18 Copyright © 2022 by Nelson Education Ltd.  Tight junctions a. Firmly bind adjacent cells together b. Seal off the passageway between the two cells c. Found primarily in sheets of epithelial tissue d. Prevent undesirable leaks within epithelial sheets 19 Copyright © 2022 by Nelson Education Ltd.  Gap junctions a. Small connecting tunnels formed by connexons b. Especially abundant in cardiac and smooth muscle 20 Copyright © 2022 by Nelson Education Ltd.  Membrane Transport a. Cell membrane is selectively permeable b. Two properties of particles that influence permeability: i. - Relative solubility of particle in lipid ii. - Size of the particle 21 Copyright © 2022 by Nelson Education Ltd.  Membrane Transport A. Unassisted membrane transport i. Osmosis ii. Diffusion B. Assisted membrane transport i. Carrier-mediated transport ii. Facilitated transport iii. Active transport iv. Vesicular transport 22 Copyright © 2022 by Nelson Education Ltd.  Membrane Transport Osmosis is net diffusion of water down its concentration gradient 23 Copyright © 2022 by Nelson Education Ltd.  Membrane Transport Tonicity of a solution (Page 40- 41) a. Isotonic solution b. Hypotonic solution c. Hypertonic solution 24 Copyright © 2022 by Nelson Education Ltd.  Membrane Transport Diffusion a. Molecules move from area of high concentration to area of low transport b. Plays a role in - Exchange of oxygen and carbon dioxide between blood and air in lungs - Movement of substances across kidney tubules 25 Copyright © 2022 by Nelson Education Ltd.  Diffusion 26 Copyright © 2022 by Nelson Education Ltd.  Membrane Transport-Diffusion 27 Copyright © 2022 by Nelson Education Ltd.  Membrane Transport Factors affecting rate of diffusion collectively make up Fick’s law of diffusion: a. Concentration gradient b. Permeability of the membrane to the substance (lipid solubility and molecular weight) c. Surface area of the membrane across which diffusion is taking place d. Thickness of the membrane 28 Copyright © 2022 by Nelson Education Ltd.  Membrane Transport Assisted membrane transport A. Carrier-mediated transport i. Accomplished by membrane carrier flipping its shape ii. Can be active or passive 29 Copyright © 2022 by Nelson Education Ltd.  Membrane Transport B. Facilitated diffusion a. Substances move from a higher concentration to a lower concentration b. Requires carrier molecule c. Example 30 Copyright © 2022 by Nelson Education Ltd. 31 Copyright © 2022 by Nelson Education Ltd.  Membrane Transport C. Active transport a. Moves a substance against its concentration gradient b. Requires a carrier molecule c. Can be accomplished by two means: Primary active transport Secondary active transport 32 Copyright © 2022 by Nelson Education Ltd. 33 Copyright © 2022 by Nelson Education Ltd.  Primary Active Transport Requires direct use of ATP 34 Copyright © 2022 by Nelson Education Ltd. 35 Copyright © 2022 by Nelson Education Ltd.  Secondary Active transport Driven by an ion concentration gradient established by a primary active transport system Refer to Figure 2-22 on page 46 (5th edition) 36 Copyright © 2022 by Nelson Education Ltd.  Membrane Transport D. Vesicular transport a. Material is moved into or out of the cell wrapped in membrane b. Active method of membrane transport 37 Copyright © 2022 by Nelson Education Ltd.  Membrane Transport a. Two types of vesicular transport: 1. Endocytosis Pinocytosis - - Receptor-mediated endocytosis - Phagocytosis 2. Exocytosis - Provides mechanism for secreting large polar molecules 38 Copyright © 2022 by Nelson Education Ltd.  PINOCYTOSIS 39 Copyright © 2022 by Nelson Education Ltd.  RECEPTOR-MEDIATED ENDOCYTOSIS 40 Copyright © 2022 by Nelson Education Ltd.  PHAGOCYTOSIS 41 Copyright © 2022 by Nelson Education Ltd.  EXOCYTOSIS 42 Copyright © 2022 by Nelson Education Ltd.  GOLGI AND EXOCYTOSIS 43 Copyright © 2022 by Nelson Education Ltd.  Intercellular Communication and Signal Transduction Copyright © 2022 by Nelson Education Ltd.  Figure 2-26: Types of Intracellular Junctions Copyright © 2022 by Nelson Education Ltd.  Chemical Messengers Five types of chemical messengers: 1. Autocrines 2. Paracrines 3. Neurocines: a) Neurotransmitter b) Neuromodulator (Neuropeptide) c) Neurohormone Copyright © 2022 by Nelson Education Ltd.  Chemical Messengers 4. Hormones: a) Hydrophilic b) Lipophilic 5. Cytokines Copyright © 2022 by Nelson Education Ltd.