Lab 1 Transport Across Cell Membrane - 2024/2025 PDF

Faculty of Medicine Transport Across the Cell Membrane Academic Year: 2024/2025...

Faculty of Medicine Transport Across the Cell Membrane Academic Year: 2024/2025 By: Naema gomaa Year: 1 Semester: 1 transport Across the Cell Membrane Module: HUMAN BODY FUNCTION (HBF-102) Department: physiology 20 December 2024 Module: HBF-102 2 OBJECTIVES INTRODUCTION Transport across cell membrane is either passive transport or active Differentiate between the types of transport across cell transport. membrane. Passive means that it doesn't need energy for transport while active list the different types of channels. means that it needs energy. Identify the different types of carriers. Passive transport is of two types simple diffusion or facilitated diffusion Mention how macromolecules can cross cell membrane Active transport is either primary or secondary. Define the term osmosis and osmotic pressure. Recognize the different types of channels Recognize the different types of channels ReRecognizethe 20 December 2024 different types Module: of channels HBF-102 3 20 December 2024 Module: HBF-102 4 cognize the different types of channels  Differentiate between passive and active transport Simple diffusion across cell membrane It is passive transport , doesn't need energy It doesn't need carrier. particles moves according to their concentration gradient Downhill transport, from high concentration to low concentration. It is affected by Fick's law of diffusion 20 December 2024 Module: HBF-102 5 20 December 2024 Module: HBF-102 6 Demonstrate diffusion in fluids and the effect of Fick’s law of diffusion temperature on its rate Procedure: Diffusion 1- Place several crystals of Fick’s law of diffusion: coefficient methylene blue in three beakers Diffusion rate (amount of the substance moved/unit time) containing water that is cold (5oC), at room temperature (25oC) and Solubility of the permeability coefficient X Conc. gradient X surface area substance hot (50oC) respectively. = ------------------------------------------------------------------------------- DC  ----------------------- Thickness of membrane ---------------------- 2-Record the time required for the  Molecular weight dye to become evenly dispersed throughout the beakers Increase temperature increase the rate of diffusion 20 December 2024 Module: HBF-102 7 20 December 2024 Module: HBF-102 8  Can charged molecules pass easily through cell membrane? 2- Ion channels Their diffusion is extremely low due to: These are important ways for diffusion of ions The formation of hydrated ions with water, which have Ions move by simple diffusion according to their electrochemical large size. gradient The interaction between their charges and the charges on leakage, voltage-gated and ligand-gated channels the cell membrane 20 December 2024 Module: HBF-102 9 20 December 2024 Module: HBF-102 10 Q3: Can you explain the direction of movement 1- leakage channels of ions in each channel? These are watery pathway through integral protein part of cell membrane They are tubed shape extending from ECF to ICF They are highly selective channels. Example: Na leakage channels and K leakage 20 December 2024 Module: HBF-102 11 20 December 2024 Module: HBF-102 12  Answer Gated channels They have gates that can open or close to various signals Ions moves according to its electrochemical A- ligand gated channels : they open or close by binding certain gradient ligand substance like neurotransmitter acetyl choline Example : Na ligand gated channels Sodium is the chief ECF cation, inside of the cell B- Voltage gated channels : they open or close by alteration of is negative compared to the outside membrane electrical potential Example : Na voltage gated channels and K voltage gated channels Potassium ion is the chief intracelullar cation, so it moves from inside to outside 20 December 2024 Module: HBF-102 13 20 December 2024 Module: HBF-102 14 : Deduce the role of sodium channels in the mechanism of action of local anesthetics Answer local anesthetics bind to voltage gated Na channels Block entry of Na to inside of the cell No generation and conduction of action potential (no pain sensation) 20 December 2024 Module: HBF-102 15 20 December 2024 Module: HBF-102 16  3- Facilitated diffusion Transport maximum It is a passive transport that follows Transport maximum is the Maximal rate at the concentration gradient which they can transport a particular solute. It doesn't need energy It depends on the number of carriers It depends on carrier protein Number of carriers is affected by hormones It has a transport maximum Diabetes milletus ; decrease in glucose carriers Example ; transport of glucose Insulin increase the number of glucose carrier 20 December 2024 Module: HBF-102 17 20 December 2024 Module: HBF-102 18 Q6: From the following diagram, name the 2 different types of transport Answer Figure A: Simple diffusion Particles diffuse directly through the cell membrane From the high concentration to the low concentration No carrier B A 20 December 2024 Module: HBF-102 19 20 December 2024 Module: HBF-102 20  Answer Active transport Figure B: Facilitated diffusion Solutes move against concentration Particles diffuse through the cell gradient. membrane using a carrier Needs energy. Needs carrier protein. From the high concentration to the Types : primary active transport and low concentration secondary active transport No energy used 21 20 December 2024 Module: HBF-102 20 December 2024 Module: HBF-102 22 Q: What is the name of this carrier? and why? Primary active transport The carrier has an ATPase activity Uphill transport Primary active Pumps Na+-K+ pump Ca+2 pump H+-K+ pump 20 December 2024 Module: HBF-102 23 20 December 2024 Module: HBF-102 24  Answer Secondary active transport Sodium potassium pump ▪ It is an active transport It is a carrier that uses ATPase Na+-K+ enzyme directly= primary ▪ depends on sodium gradient pump Na+ active transporter created by sodium K+ potassium pump This pump pumps sodium ▪ It is either cotransport or ions to the ECF and counter-transport. potassium to ICF (against their concentration Na+ gradient) K+ 20 December 2024 Module: HBF-102 25 20 December 2024 Module: HBF-102 26 : Q11 Explain the difference between the type of transport at A and B Exocytosis It is transport to outside the cell. Fusion of Secretion of secretory vesicle B Active process , require Secretory vesicle vesicle with plasma contents energy. membrane A Example ; transport of acetyl choline at motor end plate Nucleus of cell 20 December 2024 Module: HBF-102 27 20 December 2024 Module: HBF-102 28  Name this type of transport Endocytosis Transport to inside of cell Active process , require energy. Example; phagocytosis of bacteria and dead tissue 20 December 2024 Module: HBF-102 29 20 December 2024 Module: HBF-102 30 Demonstrate osmosis as a mechanism of transport Osmosis across the cell membrane It is passive transport of water across semi-preamble Procedure membrane. 1- Cut five pieces out of a potato (8 – 10 mm diameter), diffusion of water from area of high concentration water to each measuring about 5 cm long. area of low concentration of water. Or from area of low solute concentration to area of high solute 2- Determine the volume of each piece by immersing it in a concentration known volume of water in a 20 ml graduate cylinder and noting the volume rise of water in the cylinder. 20 December 2024 Module: HBF-102dif 31 20 December 2024 Module: HBF-102 32  Osmosis Results 3- Immerse one piece of the potato in one of the following five solutions: Distilled water, 0.4% NaCl, 0.9% NaCl, 5% NaCl and 10% NaCl. 4- After 2 hours, measure the volume of each piece of potato again and express the changes as a percent of the original volume 20 December 2024 Module: HBF-102 33 20 December 2024 Module: HBF-102 34 Isotonic solutions Hypotonic solution Solute concentration inside Solutes concentration inside the cell equal to solution the cell is higher. outside the cell Water is transported to The amount of water enter inside the cell. the cell equal to amount of water transported outside the cell Cell swells if exposed to extracellular hypotonicity 20 December 2024 Module: HBF-102 35 20 December 2024 Module: HBF-102 36  Hypertonic solution Osmotic pressure Solutes concentration inside the cell Osmotic pressure of a solution is the is lower. pressure required to applied on the Water is transported to outside the concentrated solution to prevent cell. water movement from diluted side Cell shrinks if exposed to (prevent osmosis ) extracellular hypertonicity 20 December 2024 Module: HBF-102 37 20 December 2024 Module: HBF-102 38 References 20 December 2024 Module: HBF-102 39