University:
Glendale Community College
Course:
BIO160 | Introduction to Human Anatomy and Physiology
Academic year:

2022
Views:

460

Pages:

5
Author:

arborezmv

Section 2.1: Basic Themes §Water §Unique polar structure +H O+H §Hydrophilic – water loving §Hydrogen bond §Hydrophobic - water fearing §Coalesce into droplets Figure 2.2 Hydrophobic Interactions Between Water and a Nonpolar Substance Section 2.1: Basic Themes §Biological Membranes – provide support & control flow in/out §Thin, flexible, and stable sheet-like structures enclosing cells & some internal cellular components §Selective physical barrier between external/internal environment §Two-dimensional supramolecular complexes consist of lipid bilayers §Held together by noncovalent intermolecular forces §Chemically reactive §Polar surfaces; attached proteins §Phospholipid bilayer with integral and peripheral membrane proteins §Involved in: transport, response to stimuli, cell-cell contact catalytic functions Section 2.1: Basic Themes Phospholipid bilayer §Uniquely suited for structure role §Hydrophilic head – charged or uncharged polar group §hydrophobic tail – fatty acid chains §Membrane Proteins §Integral proteins – embedded within membrane §Peripheral proteins – attached to outside of bilayer §Functions: §Channel proteins – transport specific ions §Carrier proteins – transport specific molecules Figure 2.3 Membrane Structure §Receptors – binding sites for extracellular ligands Section 2.1: Basic Themes §Self-Assembly §Many biomolecules spontaneously undergo selfassembly into supermolecular structures §Molecular Machines §Many multisubunit complexes involved in cellular processes function as molecular machines Figure 2.5 Biological Machines Section 2.1: Basic Themes Figure 2.6 Volume Exclusion Macromolecular Crowding §Lots macromolecules exist in low concentrations in a confined space ü Excluded volume: volume occupied by macromolecules; between 20% and 40% Signal Transduction – process for receiving & interpreting information, Ca2+ universal signaling device §Reception – signal molecule binds to receptor §Transduction – conversion of primary message to secondary message §Response – signaling cascade §Termination – efficiency & effectiveness signal mechanisms require timely termination