Chemistry of Life Unit When water, H2O, is created, hydrogen and oxygen share the electrons The oxygen has a slightly negative charge The hydrogen’s have a slightly positive charge This uneven pattern of charge creates a polar molecule = has a positive side and negative side

Water Molecule

Hydrogen Bonding Hydrogen Bond = an attraction between a slightly positive hydrogen atom and a slightly negative atom, often oxygen or nitrogen

Hydrogen Bonding

Properties Related to Hydrogen Bonding Life depends on hydrogen bonds in water High Specific Heat = water resists changes in temp. - helps regulate cells

Properties Related to Hydrogen Bonding (cont) Cohesion = attractive forces between particles of the same kind - example: surface tension of water

Surface Tension

Surface Tension – Floating Paper Clips

Catching Fleas with Soapy Water

Properties Related to Hydrogen Bonding (cont) Adhesion = the attractive forces between unlike substances - example: meniscus curve in a graduated cylinder

Meniscus Curve

Properties Related to Hydrogen Bonding (cont) Capillarity = the ability of water to move up through narrow tubes against gravity - due to cohesion and adhesion - example: carnations turning a different color in colored water

Carnations in Colored Water

Solutions The polarity of water makes it very effective at dissolving many substances Solvent + Solute = Solution Concentration [ ] = amount of solute in a given amount of solvent Saturated = no more solute will dissolve in the solvent

Solvent + Solute = Solution

Mosquito injects a solution into your body that prevents clotting

Other Types of Solutions Solutions can involve different states of matter (not just solvents that are liquids and solutes that are solids). Here are some examples….

Other Types of Solutions – Air Air is a gas mixture of mostly Nitrogen (78%), Oxygen (~ 21%), and other gases (~ 1%)

Other Types of Solution - Brass Brass is a solid mixture of Copper (~67%) and Zinc (~33%)

Other Types of Solutions - Vinegar Vinegar is a liquid solution of two liquids: 95 % Water And 5% Acetic Acid

Solutions (cont) Water is the universal solvent. All processes necessary for life take place in water.

Acids and Bases Acid = compound that releases a hydrogen ion (H+) when dissolved in water - increases the H+ [ ] Base = compound that remove H+ ions from a solution - lowers the H+ [ ]

Acids and Bases (cont) pH scale = amount of H+ ions in a solution 0 to 6 = acidic 7 = neutral 8 to 14 = basic buffer = compound that regulates H+ [ ] - maintains homeostasis

Examples of Buffers

pH Scale

Car Analogy for Organic Compounds Toyota Camry Toyota Supra

Organic Compounds Carbon is the building block of life - can form multiple bonds (up to 4), including other carbon atoms More than 90 % of the mass of all living things are composed of combinations of just 4 elements 1) Carbon ( C) 2) Hydrogen (H) 3) Oxygen (O) 4) Nitrogen (N)

1) Carbohydrates Examples sugars starches cellulose glycogen Specifics - contain C, H, and O - main source of usable chemical energy for cells - major part of plant cell wall (made of cellulose) - most basic are simple sugars = monosaccharides (glucose) - bond to form polysaccharides

1) Carbohydrates

Field of Cotton

2) Lipids Examples Fats Oils Cholesterol Specifics - contain C, H, and O - store large amounts of energy - cell membrane made up of phospholipids - regulate body responses and control sexual development - are nonpolar molecules (don’t dissolve in water)

Saturated Fats (solid at room temp)

Unsaturated Fats (liquid at room temp)

3) Proteins Examples Specifics - contain C, H, O, and N - made of monomers called amino acids - 20 different amino acids build proteins - specific sequence determines structure and function

Red Blood Cells and Sickle Cell Anemia (SEM 3500x)

4) Nucleic Acids - work together to make proteins Functions: – stores info to build proteins – helps build proteins Types: 1) DNA 2) RNA

Chemical Reactions = change substances into different substances by breaking and forming chemical bonds

6O 2 + C 6 H 12 O 6 6CO 2 + 6H 2 O 1. Reactants = substances changed during a chemical reaction (left side) 2. Direction 3. Products = substances made during a chemical reaction (right side)

* Chemical reactions release or absorb energy

Types of Chemical Reactions Activation Energy = the amount of energy needed to start a reaction - is very high in most chemical reactions (especially in the body)

Activation Energy

Types of Chemical Reactions (cont) Exothermic = chemical reaction that releases more energy than it absorbs - gives off heat (hot) - ex: cellular respiration

Exothermic Reaction

Glowsticks

Bioluminescence

Types of Chemical Reactions (cont) Endothermic = chemical reaction that absorbs more energy than it releases - absorbs heat (cold) - ex: photosynthesis

Endothermic Reaction

Cold packs

Exothermic ReactionEndothermic Reaction

Enzymes Catalyst = substance that reduces the amount of activation energy that is needed to start a chemical reaction Catalysts are not changed during a chemical reaction Enzymes = a type of catalyst in living things

Enzymes (cont) - almost all are proteins - work best in normal body conditions (temp. and pH) - specific shape allows only certain reactants to bind - fit like a lock and key

Lock and Key Model - Enzymes

Enzymes (cont) - functions: 1) help bring substrates together and chemical reactions occur 2) decrease the activation energy of the reaction 3) increase the rate of the reaction

Enzymes reduce Activation Energy

Enzymes (cont) - Reaction 1 requires more activation energy than Reaction 2 - Reaction 3 has less activation energy due to a catalyst being used

Enzymes in Your Life