Biochemistry Honor’s Biology

Carbon-based Molecules Although a cell is mostly water, the rest of the cell consists mostly of carbon-based molecules Organic chemistry is the study of carbon compounds that are necessary for life

Uses of Organic Compounds Americans consume an average of 140 pounds of sugar per person per year Cellulose, found in plant cell walls, is the most abundant organic compound on Earth

Uses of Organic Molecules A typical cell in your body has about 2 meters of DNA A typical cow produces over 200 pounds of methane gas each year

Carbon is a Versatile Atom It has four electrons in an outer shell that holds eight Carbon can share its electrons with other atoms to form up to four covalent bonds

Carbon can use its bonds to:: Attach to other carbons Form an endless diversity of carbon skeletons

Giant Molecules - Polymers Large molecules are called polymers Polymers are built from smaller molecules called monomers Biologists call them macromolecules

Examples of Polymers Proteins Lipids Carbohydrates Nucleic Acids

Most Macromolecules are Polymers Polymers are made by stringing together many smaller molecules called monomers Nucleic Acid Monomer

This process joins two sugar monomers to make a double sugar Linking Monomers Cells link monomers by a process called dehydration synthesis (removing a molecule of water) Remove H H2O Forms Remove OH This process joins two sugar monomers to make a double sugar

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

Breaking Down Polymers Cells break down macromolecules by a process called hydrolysis (adding a molecule of water) Water added to split a double sugar

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

Macromolecules in Organisms There are four categories of large molecules in cells: Carbohydrates Lipids Proteins Nucleic Acids

4 Categories of Macromolecule Carbohydrates: Made up of monosaccharides Lipids: Made up of glycerol and fatty acid molecules Proteins: Made up of Amino acids Nucleic acids: Made up of nucleotides

Carbohydrates Carbohydrates are made up of simple sugars (monosaccharides): Small sugar molecules in soft drinks Long starch molecules in pasta and potatoes Copyright Cmassengale

FUNCTION of Carbohydrates: Carbohydrates provide your cells with energy! They are your primary source of energy!

Carbohydrates Examples: A. monosaccharide B. disaccharide C. polysaccharide

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

Monosaccharides: Called simple sugars Include glucose, fructose, & galactose Have the same chemical, but different structural formulas C6H12O6

-OSE ending means SUGAR Monosaccharides Glucose is found in sports drinks Fructose is found in fruits Honey contains both glucose & fructose Galactose is called “milk sugar” -OSE ending means SUGAR

Isomers Glucose & fructose are isomers because they’re structures are different, but their chemical formulas are the same

In aqueous (watery) solutions, monosaccharides form ring structures

Cellular Fuel Monosaccharides are the main fuel that cells use for cellular work ATP

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

Disaccharides A disaccharide is a double sugar They’re made by joining two monosaccharides Involves removing a water molecule (dehydration synthesis)

Common disaccharides include: Sucrose (table sugar) Lactose (Milk Sugar) Maltose (Grain sugar)

Disaccharides Maltose is composed of 2 glucose molecules Sucrose is composed of glucose + fructose Maltose is composed of 2 glucose molecules Lactose is made of galactose + glucose GLUCOSE

Carbohydrates Polysaccharide: many sugar units Examples: starch (bread, potatoes) glycogen (stored in liver) cellulose (lettuce, corn) glucose cellulose

Polysaccharides Complex carbohydrates Composed of many sugar monomers linked together Polymers of monosaccharide chains

Examples of Polysaccharides Glucose Monomer Starch Glycogen Cellulose

Starch Starch is an example of a polysaccharide in plants Plant cells store starch for energy Potatoes and grains are major sources of starch in the human diet

Glycogen Glycogen is an example of a polysaccharide in animals Animals store excess sugar in the form of glycogen Glycogen is similar in structure to starch because BOTH are made of glucose monomers

Cellulose Cellulose is the most abundant organic compound on Earth It forms cable-like fibrils in the tough walls that enclose plants It is a major component of wood It is also known as dietary fiber

Cellulose SUGARS

Dietary Cellulose Most animals cannot derive nutrition from fiber They have bacteria in their digestive tracts that can break down cellulose

Sugars in Water Simple sugars and double sugars dissolve readily in water WATER MOLECULE They are hydrophilic, or “water-loving” -OH groups make them water soluble SUGAR MOLECULE

Lipids - fats Lipids are hydrophobic –”water fearing” Do NOT mix with water Examples include fats, waxes, oils and steroids FAT MOLECULE

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 Five functions of lipids: 1. Long term energy storage 2. Protection against heat loss (insulation) 3. Protection against physical shock 4. Chemical messengers (hormones) 5. 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 =

Triglyceride Fatty Acid Chains Glycerol

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

Types of Fatty Acids Saturated fatty acids have the maximum number of hydrogens bonded to the carbons (all single bonds between carbons) Unsaturated fatty acids have less than the maximum number of hydrogens bonded to the carbons (a double bond between carbons)

Types of Fatty Acids Single Bonds in Carbon chain Double bond in carbon chain

Fats in Organisms Most animal fats have a high proportion of saturated fatty acids & exist as solids at room temperature (butter, margarine, shortening)

Fats in Organisms Most plant oils tend to be low in saturated fatty acids & exist as liquids at room temperature (oils)

Fats Dietary fat consists largely of the molecule triglyceride composed of glycerol and three fatty acid chains Fatty Acid Chain Glycerol Condensation links the fatty acids to Glycerol

Lipids & Cell Membranes Cell membranes are made of lipids called phospholipids Phospholipids have a head that is polar & attract water (hydrophilic) Phospholipids also have 2 tails that are nonpolar and do not attract water (hydrophobic)

Steroids The carbon skeleton of steroids is bent to form 4 fused rings Cholesterol Cholesterol is the “base steroid” from which your body produces other steroids Estrogen Testosterone Estrogen & testosterone are also steroids