Cell Chemistry Climate Connections npr.org

Organic compounds Contain carbon Found in living things Made up of some or all of these elements C: carbon H: hydrogen O: oxygen N: nitrogen

Carbohydrates Elements: CHO Structure: made up of simple sugars Polysaccharide: many sugars linked Function: store and release energy Examples: glucose (sugar), starch, glycogen, cellulose

Starch Glucose Section 2-3 Figure 2-13 A Starch Carbohydrate structure

Glucose – main source of energy Cellulose – plants only, support Glycogen – animals store glucose in this form Energy is released when bond is broken!!

Lipids Elements: CHO Structure: glycerol + fatty acids Saturated fats: all C have single bonds Unsaturated fats: at least one double bond Functions: energy storage, cell membranes, insulation, waterproof coverings Examples: fats, oils, waxes, steroids phospholipids

TriglyceridePhospholipid Lipid structure

Do not dissolve or break apart in water Lipids in animals are fats Lipids in plants are oils Lipids store energy from excess food

Proteins Elements: CHON, sometimes S Structure: chain of amino acids held together by peptide bonds Functions: tissue structure, cell metabolism, transport, immunity, regulation Examples: enzymes, hemoglobin, antibodies, hormones, insulin

General structureAlanineSerine Section 2-3 Amino groupCarboxyl group Amino acid structure

Amino acids Section 2-3 Protein structure

Nucleic Acids Elements: CHONP Structure: made up of nucleotides Nucleotide: phosphate group – simple sugar – nitrogen base Functions: genetic code Examples: DNA, RNA

Nucleotide structure

You are what you eat!! Make a list of what you ate for supper last night. Beside each food, write which organic molecules are found in that food. Carbohydrates Lipids Proteins

Tests Benedict’s Solution = sugars Blue solution turns orange/rust color if sugar is present Iodine = starch Yellow solution turns blue/black if starch is present Sudan III – lipids Stains fats reds in liquids Brown paper bag – lipids Makes a mark on bag if fat is present

Chemical reactions Bonds are broken and formed to create new compounds. Atoms are neither created nor destroyed, just rearranged. Reactant + reactant  Product(s) 2 H 2 + O 2  2H 2 O Chemical reactions should “balance”.

Chemical reactions Depend upon the right conditions: Temperature pH Energy available Always involve a change in energy Some release energy; may occur spontaneously Some absorb energy; need an energy source.

Activation Energy Energy required to start a chemical reaction

Enzymes Proteins that speed up chemical reactions by lowering the activation energy

Enzymes Properties of enzymes Specific: only work with one reaction Reusable: unchanged during reaction Affected by temp and pH changes Action of enzymes E + S  ES  P + E S = substrate (what the enzyme acts upon) E = enzyme, P = product formed

End Show 2–4 Chemical Reactions and Enzymes Slide 21 of 34 Copyright Pearson Prentice Hall Enzyme Action An Enzyme-Catalyzed Reaction

Video 4 Watch this computer animation of enzyme action! Video 4 Enzymatic Reactions Here are some animations that explain enzyme action.

pH Measure of acidity Controlling pH is important to maintain homeostasis Buffers are solutions that prevent sudden changes in pH