UNIT 1 – UNDERSTANDING LIFE ON EARTHBIOMOLECULES

INTRO TO BIOCHEMISTRY

What elements from the periodic table support all life on Earth?Answer:•CARBON•HYDROGEN•OXYGEN•NITROGEN•PHOSPHORUS

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Carbon-based Molecules:

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Organic chemistry: study of carbon compounds

Carbon has 4 electrons in an outer energy level that holds eight; Can form 4 covalent bonds with many other elements

Shape of Organic Molecules:

shape=function

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The shape determines

its function in

an organism

Giant Molecules – Polymers:•Large molecules are called polymers

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• Monomers link together to form larger molecules called polymers

• Biologists call polymers macromolecules or biomolecules

Linking Monomers:

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Cells link monomers by removing a molecule of water

Remove H

Remove OH

H2O Forms

this process is called dehydration synthesis.

Breaking Down Polymers:• Cells break down macromolecules by adding a molecule of water• this process is called hydrolysis

FYIWhen trying to lose weight, dietitians tell patients to drink more water to help in the breakdown and absorption of molecules. 8

Macromolecules in Organisms:There are four macromolecules:

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Carbohydrates (CHO)

Lipids (CHO)

Proteins (CHON)

Nucleic Acids (CHONP)

CARBOHYDRATES

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Monosaccharides:•Monosaccharides are the monomers of carbohydrates; also called simple sugars• Examples: glucose, fructose, & galactose• Chemical Formula for monosaccharides is C6H12O6; this a ratio of 1:2:1

•Monosaccharides are the main fuel that cells use for cellular work; they are a source of quick energy•Disaccharides (2 Sugars bonded); example – sucrose (table sugar)

Polysaccharides:

Large sugar molecules; take longer for body to break down• Starch is an example of a polysaccharide in plant cells• Glycogen is a polysaccharide found in animal cells• Starch and glycogen are extra amounts of sugar taken in by the cell and stored for later use• Cellulose is a polysaccharide found in plant cell walls; most abundant organic compound on earth

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LIPIDS

Lipids:• Lipids are hydrophobic –”water fearing”; they do not mix with water• Includes fats, waxes, steroids and oils• Functions –store energyInsulate bodyCushion and protect organsForm cell membranes

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Structure of Lipids:• Triglyceride - Monomer of lipids Composed of 1 glycerol molecule and 3 fatty acid chains Glycerol forms the “backbone” of the triglyceride• Triglycerides are composed mainly

of carbon and hydrogen; oxygen is found only in the glycerol molecule

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•Most animal lipids exist as solids at room temperature (butter, lard, fat layer on steak/chicken, waxes)

•Most plant lipids tend to exist as liquids at room temperature (peanut, sunflower, canola oils)

Lipids in Organisms:

Lipids & Cell Membranes:• Cell membranes are made of phospholipids

• Phospholipids have a head that is polar; it attracts water (hydrophilic)

• Phospholipids also have 2 tails that are nonpolar and do not attract water (hydrophobic) 17

Steroids:• Cholesterol is the

“base steroid” from which your body produces other steroids

• Estrogen and testosterone are examples of these other steroids

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PROTEINS

Proteins:• Proteins are large, folded polymers made of monomers called amino acids• Elements in proteins: C, H, O and N• Functions:Build cellsAct as hormonesAct as enzymesCellular transport

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Linking Amino Acids:•This process is done by the ribosomes in the cell by removing a water molecule from the amino acids•The process is called a condensation or dehydration reaction; forms peptide bonds

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Enzymes are proteins

•What do enzymes do?• Enzymes control the rate of chemical reactions• Enzymes are also referred to as biological catalysts• enzymes work by weakening bonds and lowering the amount of activation energy needed for the reaction

• Enzymes act on a substrate; they are specific to substrate

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Enzyme + Substrate = Product:

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NUCLEIC ACIDS

Nucleic Acids

•Store hereditary information

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• Contain information for making all the body’s proteins

• Elements in nucleic acids: C, H, O, N and P

• Types of nucleic acids: DNA and RNA

•Nucleic acids are polymers; Nucleotides are the monomers•Nucleotides are composed of: 5-carbon sugar phosphate group nitrogeneous base

Nitrogeneous Bases:

•Each DNA nucleotide has one of the following bases:

• Each RNA nucleotide has one of the following bases:

–Adenine (A)

–Guanine (G)

–Uracil (u)

–Cytosine (C)27

–Adenine (A)

–Guanine (G)

–Thymine (T)

–Cytosine (C)

Shape of dna and rna:• One strand of

RNA forms a single helix

• Two strands of DNA join together to form a double helix

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ATP

•ATP is the energy currency of cells

•Made of a nucleotide with 3 phosphate groups

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