{[ promptMessage ]}

Bookmark it

{[ promptMessage ]}

Chapter 2 and 3

Chapter 2 and 3 - 1 2 1 2 Overview of Chemistry Cell...

Info iconThis preview shows pages 1–3. Sign up to view the full content.

View Full Document Right Arrow Icon
8/27/2008 1 Overview of Chemistry & Cell Biology Chemical Elements in the Body (Table 2-1) Major elements : ~ 99.3% Oxygen Carbon Hydrogen Nitrogen Minor elements : ~ 0.7% Calcium Phosphorus Chlorine Magnesium Potassium Sodium Sulfur Atomic Structure Nucleus protons (+ve) + neutrons (0) weight of protons ~ weight of neutrons Electrons: -ve charged particles in orbitals determine how the atom will react chemically # Protons = # Electrons overall an atom is electrically neutral Properties of Atoms Atomic # = # of protons Atomic mass (wt.)= wt. protons + wt. neutrons The Hydrogen (H) atom is the simplest atom with only 1 proton, 1 electron, & NO neutrons Isotopes Multiple forms of the same atom having the same # of protons & electrons, but differ in the # of neutrons Ions Atoms which gain or lose an electron If an atom loses an electron + vely charged ion CATIONS = +vely charge ions, e.g. sodium ion (Na + ) calcium ion= (Ca ++ ) If an atom gains an electron - vely charged ion ANIONS = -vely charged ions, e.g. chloride ion (Cl - ) carbonate ion (HCO 3 - ) Ions have the ability to conduct electricity when dissolved in water (i.e. electrolytes) Molecules & Compounds Molecule: 2 or more atoms unite may be same (e.g. O 2 ) or different (H 2 O) Compounds: 2 or more different elements unite e.g. H 2 O, CO 2 , CH 4 Chemical Bonds Forces of attraction that hold atoms together 1 2 1 2 3 4 5 6 7 8 9
Background image of page 1

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full Document Right Arrow Icon
8/27/2008 2 Forces of attraction that hold atoms together Ionic Bonds electron transfer Covalent Bonds (polar & non-polar) electron sharing Hydrogen Bonds weak bonds Ionic Bonds Electron are transferred completely from one atom to another Opposing charges hold the atoms together Covalent Bonds Covalent Bonds Nonpolar: Molecules have a uniform distribution of charges Strongest chemical bonds e.g. lipids Hydrophobic Polar: One atom attracts the e - more than the other atom Does not have a net electric charge, e.g. H 2 O, sucrose Hydrophilic Hydrogen Bonds Weak, but important bonds An intermolecular force, not an intramolecular force, i.e. DO NOT bind atoms into molecules but hold molecules together Give large molecules their shape Water Universal solvent Main transport medium for gases & nutrients Distributes heat & cools the body (via evaporation) Necessary in metabolic reactions Body has ~ 40 liters (10.56 gallons) of body water % of body water as the amount of fat & age highest in the young , the thin & the muscular babies: 75% water men: 63 % women: 52% Affinity to Water Hydrophilic compounds: “water - loving” WILL dissolve in water ionic (e.g. NaCl) & polar molecules (e.g. sucrose) Hydrophobic compounds: “water - fearing” WIIL NOT dissolve in water nonpolar molecules ( e.g. lipids) Amphipathic Molecules e.g. Phospholipids When added to water they spontaneously form several structures Acids, Bases & Salts Acids : molecules that
Background image of page 2
Image of page 3
This is the end of the preview. Sign up to access the rest of the document.

{[ snackBarMessage ]}