The Chemistry of Life

Elements A substance that can not be broken down into simpler chemical substances. 90 Natural occurring. 25 essential for living organisms.

4 elements make up 96% of a human body. carbon, hydrogen, oxygen and nitrogen. See table 6.1 page 146.

ATOMS The smallest particle of an element that has the characteristics of that element.

Structure of an Atom 3 main parts; –Nucleus Protons, P+ Neutrons, n 0 –Electrons, e-

Isotopes of Elements Atoms of the same element that have different numbers of neutrons are called isotopes. Many isotopes are radioactive.

Compound A substance that is composed of atoms of two or more different elements that are chemically combined.

Covalent Compounds Also referred to as Molecular Compounds or Molecules. Made from nonmetals that share electrons to become more stable. See example on board

examples Hydrogen gas H 2 Dihydrogen monoxide (water) H 2 O Sucrose C 6 H 12 O 6

Ionic Compounds Made from ions. Always a combination of a metal and a nonmetal. Ion = a charged particle. The attractive force between 2 ions of opposite charge is known as an ionic bond.

Chemical Reactions A reaction where chemical bonds are broken and reformed. Chemical reactions occur over and over again with in living organisms.

Metabolism All the chemical reactions that occur within an organism.

Mixture A combination of substances in which the individual components retain their own properties.

Solution A mixture in which one or more substances are distributed evenly in another substance.

Acids and Bases pH is a measure of how acidic or basic a solution is. The pH scale is from 0-14.

ACID Any substance that forms hydrogen ions when dissolved in water. pH below 7 = ACIDIC

BASE Any substance that forms hydroxide ions when dissolved in water. pH above 7 = BASIC

ASSIGNMENT SA 6.1, #1-6 page 155.

WATER Water serves as a means of material transportation in organisms. Most organisms are composed of between 70 to 95% water.

Water is Polar A polar molecule is a molecule with an unequal distribution of charge.

Because Water is Polar... It hydrogen bonds to itself and to other surfaces causing CAPILLARY ACTION. It holds large molecules together.

Resists temperature change, helping to maintain a steady environment. Expands when it freezes. Ice floats, cracks rocks (soil making).

Diffusion All objects in motion have KINETIC ENERGY. Robert Brown, Scottish science dude, Observes Brownian motion.

Random motion of molecules. Because of this random motion liquids and gases have a tendency to move from areas of high concentration to areas of low concentration.

The net movement of particles from high conc. to low conc. 3 key factors that effect the rate of diffusion.

Temperature Pressure Concentration

Assignment SA 6.2page160 #1-6.

LIFE SUBSTANCES

CARBON Very Versatile. Has 4 electrons available for bonding in its outer energy level.

CARBON Can form bonds with other carbon atoms and other elements. Carbon can form single, double, and triple bonds.

CARBON Can form long chains. Straight, Branched and ringed. Compounds with the same simple formula often have a different structure.

Isomers Compounds that have the same simple formula but different three-dimensional structures. Example: Glucose C 6 H 12 O 6 and Fructose C 6 H 12 O 6

Polymers A large molecule formed when many smaller molecules bond together.

Condensation The chemical reaction by which polymers are formed. Water is given off as a byproduct.

Hydrolysis A method by which polymers break apart. Uses water to add H+ and OH- ions to the subunits that make up the polymer.

Carbohydrates Organic compound composed of carbon, hydrogen and oxygen. Ratio of 2 hydrogen atoms to every 1 oxygen atom for every carbon atom.

Carbohydrates Used by the cell to store and release energy.

Carbohydrates Three main kinds: –Monosaccharides –Disaccharides –Polysaccharides

Monosaccharides Monosaccharide: single simple sugar. –Examples: Glucose, Fructose.

Disaccharides When 2 Monosaccharides are linked together by a condensation reaction. –Example: Sucrose

Polysaccharides Polymer composed of many monosaccharides. –Examples: Starch, glycogen, cellulose.

Starch Consists of highly branched chains of glucose units. Used for food store in plants.

Glycogen Very Highly branched Used a food storage in Mammals. (stored in the liver)

Cellulose Made of long chains of glucose units hooked together. Used as structural support of plants.

Lipids Organic Compounds that have a large proportion of C-H bonds. Contain much less oxygen than carbohydrates. Example: C 57 H 110 O 6

Lipids Commonly called FATS and OILS. Insoluble in water. (nonpolar) Cells use Lipids for energy storage, insulation, and protective coatings.

Lipids Lipids are the major components of cell membranes that surround all living cells.

Protein Large complex polymer composed of carbon, hydrogen, oxygen, nitrogen and usually sulfur. Basic building blocks of proteins are called amino acids.

Protein There are 20 different amino acids. As A.A. are linked together proteins are formed.

Proteins The bonds between the A.A. are a result of condensation reactions. These bonds are called peptide bonds.

Protein The number and order of A.A. in protein chains determine the kind of protein. Examples: Muscle, transporting of oxygen, providing immunity, regulating other proteins...

Enzyme A protein that changes the rate of a chemical reaction. Involved in nearly all metabolic processes.

Nucleic acids Complex Macro molecule that stores information for the cell.

It’s made out of: –Carbon –Hydrogen –Oxygen –Nitrogen –Phosphorus

3 Main Parts Nitrogen Base Simple Sugar Phosphate Group

2 Main Kinds DNA RNA

What’s it for? RNA makes copies of DNA to make proteins.

Assignment SA 6.3 page 167, #1-5. CA 6 page 171 #1-26.