YIJC [H2] CI1.4_Membranes and Cellular Transport (N)

2023 JC1 BIOLOGY LECTURE NOTES CORE IDEA 1: THE CELL AND BIOMOLECULES OF LIFE TOPIC 1.4: MEMBRANES & CELLULAR TRANSPORT Learning Outcomes You should be able to: (j) explain the fluid mosaic model and the roles of the constituent biomolecules (including phospholipids, proteins, glycolipids, glycoproteins and cholesterol) in cell membranes (k) outline the functions of membranes at the surface of cells and membranes within the cell (l) explain how and why different substances move across membranes through simple diffusion, osmosis, facilitated diffusion, active transport, endocytosis and exocytosis Textbooks and References Campbell, Urry, Cain, Wasserman, Minorsky, Reece (2018) Biology – A Global Approach (11 th Edition)(Global Edition) Chapter 8: Cell Membranes pg. 196 – 211 (Pearson Publication) ISBN-10 1-292-17043-3 Note: This textbook is available in our library. You may wish to borrow them to supplement your reading when necessary. Contents Introduction 1.1 Fluid mosaic model of membrane structure 1.2 Roles of the constituent biomolecules in membrane 1.2.1 Phospholipids 1.2.2 Proteins 1.2.3 Glycolipids & Glycoproteins 1.2.4 Cholesterol 1.3 Functions of membranes 1.3.1 At surface of cells 1.3.2 Within the cell 2.0 Transport across membrane 2.1 Passive transport 2.1.1 Simple diffusion 2.1.2 Osmosis 2.1.3 Facilitated diffusion 2.2 Active transport 2.3 Bulk transport 2.3.1 Endocytosis 2.3.2 Exocytosis H2

2 Introduction The following question should help you frame your learning: 1. How do cells regulate the movement of substances into and out of themselves, and what are the implications of such movements? Biomolecules make up cells and cells regulate many cellular processes, including the movement of substances into and out of themselves, through membranes. Phospholipids, cholesterol, carbohydrates and proteins are important components in biological membranes. Cells need to regulate the movement of substances into and out of themselves. Substances such as water, oxygen, glucose and minerals are important in t he synthesis of new molecules and important cellular processes. According to the fluid mosaic model, cell membranes are partially permeable due to the nature of the phospholipids and proteins from which they are made. The movement of different molecules depends on the nature of the substances through transport processes such as osmosis, diffusion and active transport. Membranes allow cells to create and maintain internal environments that are different from external environments.

3 Learning Outcome (j): Explain the fluid mosaic model and the roles of the constituent biomolecules (including phospholipids, proteins, glycolipids, glycoproteins and cholesterol) in cell membranes 1.1 Fluid mosaic model of membrane structure Practices of Science ● As early as 1915 scientists were aware that the structure of membranes isolated fro