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The Macromolecules of Cells: Carbohydrates

LipidsProteins

Nucleic Acid

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Organic Molecules * Organic molecules are found in

living things (vs. Nonorganic)* Referred to as “macromolecules”

-- Carbohydrates-- Lipids-- Proteins-- Nucleic Acids

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Organic molecules are made of carbon and can

form a huge variety of carbon backbone chains.

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Macromolecules (polymers) are formed from smaller building blocks called monomers.

Polymer Monomer carbohydrates monosaccharides proteins amino acids nucleic acids nucleotides Lipids “none”

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Carbohydrates

Carbohydrates (sugars) serve as 1) quick energy and short-term

energy storage2) they play a structural role in

plants, bacteria, and insects 3) many end in the suffix “ose”

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Monosaccharides• Monosaccharides are sugars that are

made up of only one sugar. • There are only 3 monosaccharides

Glucose Fructose Galactose

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Monosaccharide -- one sugar carbohydrate

Glucose

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Disaccharides• Disaccharides are made out of two simple

sugars (monosaccharides) Sucrose (table sugar) -- glucose + fructose

Maltose (malt sugar) -- glucose + glucose

Lactose (milk sugar) -- galactose + glucose

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A disaccharide is made from linking two monosaccharides together.

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Reactions• The making or breaking of disaccharides

uses a molecule of water• Condensation: reaction makes a

disaccharide from two monosaccharides and removes a water molecule in the process.

• Hydrolysis: reaction breaks down a disaccharide by adding a water molecule to satisfy the exposed bonding sites on the two new monosaccharides.

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Condensation Reaction

• Water is removed to allow the two sugars to bond together.

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Hydrolysis Reaction

• Water is added so O- and OH+ can be added to exposed bonding sites.

• Satisfies bonds

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Larger sugars are made from linking many glucose molecules

StarchGlycogenCellulose

Chitin

Polysaccharides

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Examples of Polysaccharides:

starch -- (helical structure)energy storage in plants

glycogen

cellulose -- (unbranched) found in plants for structure. It is not available as an energy source because of structure.

Chitin – found in the exoskeleton of insects and crustaceans

(highly branched)

quick energy for animals

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Starch• Starch is a storage

molecule for plants. It is stored in structures called plastids.

• Starch is high in energy and is stored energy for the plant.

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Glycogen• Glycogen is a

molecule that is used by animals for temporary storage of energy. If not utilized, energy will be stored as fat.

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Chitin• Chitin is a

polysaccharide found in exoskeletons of crustaceans and insects.

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Cellulose• Polysaccharide

found in the cell walls of plants. Strong molecule used for structure and support of the plant cell.

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Lipids *Lipids serve as long-term energy stores

in cells, form membranes, and serve as hormones and insulation.

Lipids do not dissolve in water!!!Main reason why lipids are classified

together; all other molecules are soluble in water

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Structure of Triglycerides

Formed from a glycerol molecule and three fatty acid molecules.

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Fatty acids are long chains of carbons with many hydrogens attached. Full of energy since all bonds are potential energy for an organism.

Fatty acids may be saturated fatty acids or unsaturated fatty acids.

Fatty Acid Chains

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Saturated vs. Unsaturated“bad for you” “good for you”

• Saturated Fats have no double bonds

• Found in tropical oils and animal fats

• All carbons are “saturated” with hydrogens.

• Straight chains• Solid at room temp.

• Unsaturated Fats have varying numbers of double bonds

• Common in plants• All carbons are not fully

bonded with hydrogens• Chains are bent at

double bonds• Liquid at room temp.

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Some lipids are phospholipids that form cell membranes. These only have two fatty acids chains.

Glycerol head is hydrophilic -- loves water

Fatty Acid tails are hydrophobic -- hate water

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Other lipids are steroids -- no fatty acid chains.

Examples: Steroids -- Cholesterol (thickens arteries and is important in cell membrane) Hormones (estrogen and testosterone) Waxes

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Proteins

Proteins:1. Serve as structural proteins (cartilage, fingernails, hair, etc.) 2. Act as enzymes to speed reactions3. Serve as transport carriers 4. Act as antibodies5. Allow materials to cross membranes

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Proteins are polymers of amino acids.

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Water is removed when joining two amino acids.

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Proteins have levels of organization.

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Protein Organization• Primary Structure (1°) -- linear chain of amino

acids. Number and sequence of amino acids varies.

• Secondary Structure(2°) -- shortening of amino acid chain by coiling or pleating

• Tertiary Structure (3°) -- further folding of chain to create a more compact structure

• Quaternary Structure (4°) -- only some proteins have this structure which is two or more chains bonded together.

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Nucleic Acids

Nucleotides are monomers of nucleic acids.

Examples include Deoxyribonucleic Acid (DNA) and Ribonucleic Acid (RNA).

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DNA is double-stranded, with complementary base pairing.