BGY3002 Lect 2 Chemicals and cells PDF

BGY3002 THE CHEMICAL BASIS OF CELLS By: Assoc Prof Dr Mashitah SM  Why need to understand the To understanding chemical basis of cellular function cells? Studying chemistry is Structure and function...

BGY3002 THE CHEMICAL BASIS OF CELLS By: Assoc Prof Dr Mashitah SM  Why need to understand the To understanding chemical basis of cellular function cells? Studying chemistry is Structure and function essential for of cells are closely understanding cell related to the biology structure of molecules and atoms By: DrMashitah SM By: DrMashitah SM  The smallest chemically unbreakable unit of MATTER ? An atom By: DrMashitah SM By: DrMashitah SM Element - Any substance composed of only ONE element Ex) a bar of pure gold, nitrogen gas (N2), oxygen gas (O2) Compound - Any substance composed of two or more elements Ex) Na+Cl- (table salt), H2O, CO2 By: DrMashitah SM By: DrMashitah SM By: DrMashitah SM  What are atoms made of and how are they organized Niels Bohr ? Danish Physicist (The Bohr Model) 1885-1962 By: DrMashitah SM  Electrons can jump between shells (called as quantum leap) By: DrMashitah SM By: DrMashitah SM By: DrMashitah SM By: DrMashitah SM  A lack of iodine in one’s diet can cause swelling of the thyroid gland resulting in a GOITER. The condition is reversible if iodine is taken. (Don’t worry, we iodize salt) Iodine is used by thyroid cells to make hormones (chemicals released by one cell into the blood and bind to a receptor on another cell, which is one way cells talk to each other). By: DrMashitah SM  Isotopes are atoms that have the same elemental identity (same number of protons/same properties), but different number of neutrons. By: DrMashitah SM By: DrMashitah SM By: DrMashitah SM By: DrMashitah SM By: DrMashitah SM  Boiling Point = 100 ⁰C (212 ⁰F) at 1 atmosphere of pressure Freezing Point = 0 ⁰C (32 ⁰F) at 1 atmosphere of pressure Density = 1 g/cc (at 4 ⁰C) Nearly Colorless Tasteless Odorless By: DrMashitah SM  A Chemical Description of Water One atom of oxygen (O) is bound to two atoms of hydrogen (H) to form a 105 ⁰ angle “V” shape. This results in a molecule with a slight positive charge on one side of the molecule (H) and a slight negative charge on the other side (O) – this is called a dipole moment. Hydrogen-Bonding - this gives water many unique properties. By: DrMashitah SM  Three States of water By: DrMashitah SM  Hydrogen Bonds Bonding between molecules Very weak, but very important for the various characteristics of water… 5 Characteristics of Water: 1. Cohesion (“co-” means “together”) 2. Adhesion (stick to substance; stronger bonds than cohesion) 3. High Specific Heat (resists temperature change!) 4. Less Dense as a Solid (allows for insulation of bodies of water by floating ice) 5. Water is a terrific solvent (universal solvent) Solute – gets dissolved (Hot Cocoa mix) Solvent – does the dissolving (Water)Solution – uniform mixture of two or more substances By: DrMashitah SM By: DrMashitah SM By: DrMashitah SM  Capillary Action By: DrMashitah SM By: DrMashitah SM  Hydrophilic and Hydrophobic Substances By: DrMashitah SM