Why Carbon? What does a carbon atom look like?

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1 Biomolecules

2 Organic Chemistry In the 1800 s it was believed to be impossible to recreate molecules in a lab Thus, the study of organic chemistry was originally the study of molecules in living organisms Now, organic chemistry refers to the study of molecules containing carbon Every cell in our world contains ,000 different organic molecules

3 Why Carbon? Of the 118 elements that we know of, carbon is by far the most frequently-used element for building an organism. Carbon contains only six protons and electrons What does a carbon atom look like? Of all elements that can bond with four other atoms at once, carbon is the smallest It can form double and triple bonds It can form long chains or rings Thus, carbon is important because of it s tremendous diversity

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5 Carbon Functional Groups Carbon can bond with multiple elements, but certain elements occur more often than others Because of this, we give these combinations special names Alcohol: An OH (Hydroxyl) attached to a carbon Aldehyde: A double-bonded oxygen Carboxylic Acid: An hydroxyl and a double-bonded oxygen attached to the same carbon Amine: A Nitrogen attached to a carbon Benzene: A ring of carbons

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7 Macromolecules There are four main macromolecule categories in the biosphere Carbohydrates, Lipids, Proteins and Nucleic Acids Each macromolecule category contains a simple, single structure called a monomer. Monomers can be attached in almost infinite ways to form polymers. To attach and break monomers and polymers it s important to learn two types of reactions, condensation/dehydration and hydrolysis.

8 Condensation/Dehydration In order to attach to each other, monomers need to pair a hydroxyl (-OH) on one monomer with a hydrogen (-H) on another The hydroxyl and hydrogen molecules bond with each other to form a water molecule (hence, condensation) Each monomer then has an empty, available bond to form which they form with each other.

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10 Hydrolysis Hydrolysis is the reverse. If a polymer needs to break, it can rip apart a water molecule to re-form a hydrogen and a hydroxyl. The polymer then breaks its bond and reattaches the hydrogen and hydroxyl, forming two separate monomers.

11 Hydrolysis Reaction

12 Carbohydrates Carbohydrates, or sugars, can be used for structural support but are primarily an energy source All carbohydrates have a chemical formula equivalent to CH 2 O C 6 H 12 O 6 =Glucose, Fructose C 12 H 24 O 12 =Maltose, Sucrose A single unit is called a monosaccharide. Two monosaccharides are called disaccharides Three or more monosaccharides are called polysaccharides.

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14 Carbohydrates The most abundant carbohydrate is a glucose molecule. Glucose provides quick energy for organisms Glucose also forms polymers with other monosaccharides Maltose=two glucoses Grain sugars Sucrose=one glucose, one fructose Table sugar Lactose=one glucose, one galactose Milk sugar

15 Carbohydrates Larger polysaccharides are used for short-term energy storage or for structural support When the organism needs immediate energy, it can hydrolyze the long polysaccharides to get individual glucose molecules Starch: long branched polysaccharides in plants Glycogen: long branched polysaccharides in animals Cellulose: long, woven strands of glucose in plants Chitin: long, woven strands of glucose in animals (insects, crabs, etc)

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17 Lipids Lipids are long chains of carbons and hydrogen Lipids are incredibly strong, and insoluble Water does not easily bond to lipids Lipids are used for long-term energy storage and insulation Fats, oils, membranes and steroids are lipids, or contain a majority of lipids

18 Lipids The structure of fats and oils are triglycerides At one end of a lipid is a three carbon chain with three hydroxyl groups attached (glycerol). Through condensation, a chain of carbons (fatty acid) attaches where the hydroxyl is located The result is a glycerol holding three chains of carbons, which can be added to endlessly Saturated fatty acids have no double bonds and melt at high temperatures Butter Unsaturated fatty acids have at least one double bond and melt at low temperatures Oils

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21 Lipids We will cover these in more detail later, but there are two other categories of lipids Phospholipids Phosphates attached to lipids, used to build membranes Steroids Four fused rings of lipids Steroids are precursors (building blocks) of hormones

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23 Proteins Proteins are important for numerous different reasons in organisms Support (hair, nails, ligaments, tendons, skin) Transport (moving objects from cell to cell) Defense (antibodies) Hormones (chemical messengers) Motion (actin and myosin) Enzymes (chemical reactions) Each protein is a chain of amino acids

24 Proteins Amino Acids are four distinct branches connected to a central carbon molecule A hydrogen atom An amine (NH3) A carboxylic acid (COOH) An R group The R group is one of 20 unique structures that make up each amino acid

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27 Protein Structure Proteins are folded in 3-4 distinct levels of structure Primary Structure The first structure is the unique series of amino acids that make up a protein chain Amino acids attach through condensation reactions The bonds are called peptide bonds Peptide bonds: the carboyxlic acid of one amino acid and the amine of another

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29 Protein Structure Secondary Structure Once the chain is built, the chain folds over itself in one of two distinct patterns Alpha helix The protein chain folds into a cylinder Beta sheets The protein folds back and forth on top of itself, like an accordion In both cases, a hydrogen bond between every fourth amino acid accounts for this folding

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32 Protein Structure Tertiary Structure The R-groups on each of the amino acids have the potential to hydrogen bond with each other This is much less predictable, and results in unusual shapes This is typically the final structure Quarternary Structure In rare instances, multiple proteins can bond to each other to create a super protein. Hemoglobin is one example

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34 Nucleic Acids Nucleic Acids contain three parts A Ribose sugar, the backbone of a nucleic acid A phosphate molecule, which connects nucleic acids to each other A nitrogenous base, which is unique to each nucleic acid Nucleic Acids are the genetic code, or blueprint, of organisms The sequence of nucleic acids (and which base they have) creates this code

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38 Extra Credit Question This question is worth an extra 5% on your essay exam You may check your answers with me ahead of time for a yes or no response as many times as you like. One of the most common responses to dealing with ice on the sidewalk is to pour salt on it. In 1-2 sentences, explain why this works.