Macromolecules

Organic Compounds Compounds that contain CARBON are called organic. Macromolecules are large organic molecules.

Carbon (C) Carbon has 4 electrons in outer shell. Carbon can form covalent bonds with as many as 4 other atoms (elements). Usually with C, H, O or N. Example: CH4(methane)

Macromolecules Large organic molecules. Also called POLYMERS. Made up of smaller “building blocks” called MONOMERS. Examples: 1. Carbohydrates 2. Lipids 3. Proteins 4. Nucleic acids (DNA and RNA)

Question: How Are Macromolecules Formed?

Answer: Dehydration Synthesis Also called “condensation reaction” Forms polymers by combining monomers by “removing water”. HO H H2O HO H

Dehydration Synthesis Combining simple molecules to form a more complex one with the removal of water ex. monosaccharide + monosaccharide ----> disaccharide + water (C6H12O6 + C6H12O6 ----> C12H22O11 + H2O Polysaccharides are formed from repeated dehydration syntheses of water They are the stored extra sugars known as starch

Question: How are Macromolecules separated or digested?

Answer: Hydrolysis Separates monomers by “adding water” HO H H2O HO H

Carbohydrates used as a source of energy; short term and long term energy also some animals and organisms use carbs for structural purposes.

Carbohydrates Small sugar molecules to large sugar molecules. Examples: A. monosaccharide B. disaccharide C. polysaccharide

Carbohydrates Monosaccharide: one sugar unit Examples: glucose (C6H12O6) deoxyribose ribose Fructose Galactose glucose

Carbohydrates Disaccharide: two sugar unit Examples: (C12H22O11) Sucrose (glucose+fructose) Lactose (glucose+galactose) Maltose (glucose+glucose) glucose

Carbohydrates Polysaccharide: many sugar units Examples: starch (bread, potatoes) glycogen (beef muscle) cellulose (lettuce, corn) glucose cellulose

Lipids some store energy, some lipids form important parts of biological membranes & waterproof coverings.

Lipids General term for compounds which are not soluble in water. Lipids are soluble in hydrophobic solvents. Remember: “stores the most energy” Examples: 1. Fats 2. Phospholipids 3. Oils 4. Waxes 5. Steroid hormones 6. Triglycerides

Lipids Six functions of lipids: 1. Long term energy storage 2. Protection against heat loss (insulation) 3. Protection against physical shock 4. Protection against water loss 5. Chemical messengers (hormones) 6. Major component of membranes (phospholipids)

Lipids Triglycerides: composed of 1 glycerol and 3 fatty acids. = = H H-C----O glycerol O C-CH2-CH2-CH2-CH2-CH2-CH2-CH2-CH2-CH2-CH3 = O C-CH2-CH2-CH2-CH2-CH2-CH2-CH2-CH2-CH2-CH3 = fatty acids O C-CH2-CH2-CH2-CH =CH-CH2-CH2-CH2-CH2-CH3 =

Fatty Acids There are two kinds of fatty acids you may see these on food labels: 1. Saturated fatty acids: no double bonds (bad) 2. Unsaturated fatty acids: double bonds (good) O C-CH2-CH2-CH2-CH2-CH2-CH2-CH2-CH2-CH2-CH3 = saturated O C-CH2-CH2-CH2-CH =CH-CH2-CH2-CH2-CH2-CH3 = unsaturated

Proteins

Proteins (Polypeptides) Amino acids (20 different kinds of aa) bonded together by peptide bonds (polypeptides). Six functions of proteins: 1. Storage: albumin (egg white) 2. Transport: hemoglobin 3. Regulatory: hormones 4. Movement: muscles 5. Structural: membranes, hair, nails 6. Enzymes: cellular reactions

Major Protein Functions Growth and repair form cellular structures Energy Buffer -- helps keep body pH constant referred to as maintaining homeostasis, by transporting some substance into and out of the cells some help fight diseases Control rate of reactions

Proteins (Polypeptides) Four levels of protein structure: A. Primary Structure B. Secondary Structure C. Tertiary Structure D. Quaternary Structure

Primary Structure Amino acids bonded together by peptide bonds (straight chains) aa1 aa2 aa3 aa4 aa5 aa6 Peptide Bonds Amino Acids (aa)

Secondary Structure 3-dimensional folding arrangement of a primary structure into coils and pleats held together by hydrogen bonds. Two examples: Alpha Helix Beta Pleated Sheet Hydrogen Bonds

Tertiary Structure Secondary structures bent and folded into a more complex 3-D arrangement of linked polypeptides Bonds: H-bonds, ionic, disulfide bridges (S-S) Call a “subunit”. Alpha Helix Beta Pleated Sheet

Quaternary Structure Composed of 2 or more “subunits” Globular in shape Form in Aqueous environments Example: enzymes (hemoglobin) subunits

Nucleic Acids

Nucleic acids Two types: a. Deoxyribonucleic acid (DNA- double helix) b. Ribonucleic acid (RNA-single strand) Nucleic acids are composed of long chains of nucleotides linked by dehydration synthesis.

Nucleic acids Nucleotides include: phosphate group pentose sugar (5-carbon) nitrogenous bases: adenine (A) thymine (T) DNA only uracil (U) RNA only cytosine (C) guanine (G)

DNA Nitrogenous bases

DNA Nucleotide O O=P-O N CH2 O C1 C4 C3 C2 Phosphate Group Nitrogenous base (A, G, C, or T) CH2 O C1 C4 C3 C2 5 Sugar (deoxyribose)

RNA Nucleotide directs cellular protein synthesis found in ribosomes & nucleoli

DNA - double helix P O 1 2 3 4 5 P O 1 2 3 4 5 G C T A

Enzymes and Enzyme Action Catalyst : inorganic or organic substance which speeds up the rate of a chemical reaction without entering the reaction itself enzymes: organic catalysts made of protein most enzyme names end in -ase enzymes lower the energy needed to start a chemical reaction. (activation energy) begin to be destroyed above 45øC. (above this temperature all proteins begin to be destroyed)

It is thought that, in order for an enzyme to affect the rate of a reaction, the following events must take place. The enzyme must form a temporary association with the substance or substances whose reaction rate it affects. These substances are known as substrates. The association between enzyme and substrate is thought to form a close physical association between the molecules and is called the enzyme-substrate complex. While the enzyme-substrate complex is formed, enzyme action takes place. Upon completion of the reaction, the enzyme and product(s) separate. The enzyme molecule is now available to form additional complexes.

How do enzymes work? substrate: molecules upon which an enzyme acts the enzyme is shaped so that it can only lock up with a specific substrate molecule enzyme substrate -------------> product

Factors Influencing Rate of Enzyme Action 1. pH - the optimum (best) in most living things is close to 7 (neutral) high or low pH levels usually slow enzyme activity A few enzymes (such as gastric protease) work best at a pH of about 2.0

. 2-Temperature - strongly influences enzyme activity optimum temperature for maximum enzyme function is usually about 35-40 C. reactions proceed slowly below optimal temperatures above 45 C most enzymes are denatured (change in their shape so the enzyme active site no longer fits with the substrate and the enzyme can't function)

3-Concentration Concentrations of Enzyme and Substrate ** When there is a fixed amount of enzyme and an excess of substrate molecules -- the rate of reaction will increase to a point and then level off.

Enzymes in the Human Body 1. Carbonic anhydrase: speeds up the reaction of Carbon dioxide combining with water to produce carbonic acid to remove carbon dioxide from the body 2. Salivary amylase: catalyzes the hydrolysis of starch, begins process of digestion in mouth; 3. Pepsin (protease): helps break down proteins; 4. Lactase: breaks down the milk sugar and lactose into simpler sugars; 5. Catalase: breaks down hydrogen peroxide into water.