Molecules of Life

Chemistry, I thought this was biology? Electrolytes Fertilizer Soil pH Acid Rain Blood pH Hormones

What are living things made of? Cells Tissues Organs Organ Systems

What do Living Things DO? Interact with environment Grow Obtain nutrients Breathe Reproduce And, more! To understand this, we need to know something about… chemistry

Water: The Molecule That Supports All of Life

Water forms Hydrogen Bonds Figure 4-12 Unequal sharing of electrons in water molecules leads to many weak bonds between water molecules

Cohesion and Adhesion Cohesion: Water molecules stick together Adhesion: Water molecules are attracted to other things Fig. 4-13

Surface Tension – a consequence of hydrogen bonding in water molecules

How can we demonstrate Cohesion and Adhesion?

San Diego 72° 40 miles Pacific Ocean 70s (°F ) 80s 90s 100s Santa Barbara 73° Los Angeles (Airport) 75° Burbank 90° San Bernardino 100° Riverside 96° Santa Ana 84° Palm Springs 106° Water has a very high specific heat. It takes lots of energy to heat up and it needs to give up lots of energy before it cools. Compared to rocks and soil, water changes temperature slowly. Oceans and lakes moderate the climate of nearby coastal areas Cooler summers & milder winters

Evaporative Cooling 1.The fastest moving molecules have the most energy 2.They evaporate 3.The average molecule is now slower, a.k.a cooler!

Ice Floats (A.K.A. Low Density of Ice) Water below is insulated Fish and other life survive the winter

Figure 4-15 Ice floats because its molecules are less densely packed than those in liquid water.

Cl – Na Cl – – – – – – – – – Na + – – – + Water: the solvent of life (A.K.A. Water’s ability to dissolve other substances) Salts, enzymes and other chemicals are dissolved in the water in cells

Water Cohesion & Adhesion Moderation of Temperature Insulation of Bodies of Water by floating ice Solvent of life

Large Biological Molecules 1.Carbohydrates 2.Lipids 3.Proteins 4.Nucleic Acids

Molecules in Foods

Organic chemistry the study of carbon compounds “Organic” can mean: Carbon containing Related to life Synthetic chemical- free (agriculture) Cholera bacteria

Organic Compounds

Carbohydrate an organic molecule made up of sugar molecules

Monosaccharide –Simple sugars –One sugar unit Disaccharide –“double sugar” Polysaccharide –Long chain of sugar units –Complex carbohydrates

Hi, I’m Mason Bear, your teacher’s butter eating chocolate lab. Today, you are going to learn more about lipids – my favorite. Butter is SO YUMMY!!!

Lipids Fats, oils, waxes, steroids Do not dissolve in water

Saturated vs. Unsaturated Fatty Acids SaturatedUnsaturated

What do fatty tissues do? Store energy for later use Cushion organs Insulate

Proteins Made of amino acids Build muscle Responsible for most of our physical and chemical characteristics –Skin color –Hair color –Eye color –Height –Temperament –Metabolism

Food Guide Pyramid

Acids and Bases Occasionally water molecules break into H + and OH - ions Water is neutral (H + = OH - ) Acids have a high number of H + Bases have a low number of H +

The pH Scale pH means the “power of Hydrogen” Ranges from 0 (most acidic) to 14 (most basic)

Pure Water has pH = 7

Acids have a pH < 7

Bases have a pH > 7

Universal Indicator Solution

Buffers Resist changes in pH Accept H + when solutions become too acidic (pH is too low) Donate H + when solutions become too basic (pH is too high) Essential for maintaining homeostasis in living organisms Buffer Capacity the point at which the buffer can no longer absorb or contribute H +

Buffering Ability Water vs. A Biological Substance ccessnet.com 4.4 pg 4

Enzymes lower the energy required to start a reaction Fig. 5-15

Enzyme Vocab. Activation Energy – energy needed to start a reaction Enzyme – protein that speeds up a chemical reaction by lowering the activation energy. Enzymes are recycled, not used up. Substrate – the substance participating in a reaction aided by an enzyme Active Site – part of the enzyme that binds to the substrate; shape is very important

Proteins can be Denatured Denaturation: loss of normal shape of a protein Can be caused by heat, cold, change in pH Proteins that have be denatured don’t work well