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The Cell Membrane. Chapter 2 Section 2.1- The Components of Cells Topics: Structure, Function, Diseases. Why is the cell membrane so important?. Controls what molecules enter and leave Selectively permeable O 2 , CO 2 , and water can pass straight through membrane
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The Cell Membrane Chapter 2 Section 2.1- The Components of Cells Topics: Structure, Function, Diseases
Why is the cell membrane so important? • Controls what molecules enter and leave • Selectively permeable • O2, CO2, and water can pass straight through membrane • Charged or larger molecules need channel or carrier proteins to enter.
What are the parts of a cell membrane? • Phospholipids • Create a bilayer • Phosphate head • Hydrophilic- loves water so exposed to watery internal & external cell environment • 2 lipid tails • Hydrophobic- hate water so are found in the middle of the membrane
What are the parts of a cell membrane? • Glycoproteins- carbohydrate chains attached to proteins embedded in CM • Glycolipids- carbohydrate chains attached to phospholipids embedded in CM • Both of these help other cells recognize each other
What are the parts of a cell membrane? • Receptor Proteins • Have indentations or shapes that fit and hold molecules outside the cell. • Ligand- molecule that binds to the active site of a receptor • After ligand binds to receptor a cascade of chemical reactions occur inside cell • EX: Ligand might send a message inside the cell to tell cell to make more mucous, hormone, etc.
What are the parts of a cell membrane? • Selective channel protein- allows certain ions into/out of cell; like a tube for passive movement of larger or charged ions • Adhesion proteins- connect two bilayers to each other • Enzymes- speed up chemical reactions • Carrier protein- open and close to dump molecules in/out Carrier protein clip
What are the parts of a cell membrane? • Cholesterol • gives cell membrane some structure so it is not “mushy” • Keeps cell membrane from freezing in cold weather
Why is the cell membrane called a fluid mosaic model? • Mosaic- b/c it is studded with so many different proteins, carbohydrates, enzymes, etc. • Fluid- b/c the molecules are not rigidly joined. They are moveable around each other • Fluid Mosaic Video Clip
Cell Membrane Rap! • https://www.youtube.com/watch?v=Pfu1DE9PK2w
What types of diseases are associated with proteins in the cell membrane? • Congenital Insensitivity to Pain (CIP)- • sodium channel proteins are mutated and block sodium ions which leads to decreased or absent nerve impulses • No nerve impulses= can’t feel pain Normal Sodium Channel Video Clip
What types of diseases are associated with proteins in the cell membrane? • Paroxysmal extreme pain disorder (PE or PEPD) • Sodium channel proteins are mutated and left open too long causing a prolonged and intense pain response
What types of diseases are associated with proteins in the cell membrane? • Cystic Fibrosis (CF) • Abnormal sodium and chloride channel proteins • Sodium chloride trapped inside cell draws water out of mucous lining lungs/pancreas which causes mucous to be very thick. • CF patients have difficulty breathing due to thick mucous secretions in pancreas and lungs, & frequent lung infections