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Chapter 5:. Molecules of Life. Organic vs. Inorganic. All compounds may be classified into two broad categories: organic compounds - carbon based molecules inorganic compounds - almost all are non-carbon based molecules. Carbon (C). Carbon has 4 electrons in outer shell.
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Chapter 5: Molecules of Life
Organic vs. Inorganic All compounds may be classified into two broad categories: • organic compounds - carbon based molecules • inorganic compounds - almost all are non-carbon based 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)
Carbon Bonding • Carbon can also bond with other carbon atoms • Forms three types of structures: • Straight chains • Branched chains • Rings
Carbon bonding • Carbon can share one, two or three electrons with another atom • single bond - one electron shared • double bond - two electrons shared • triple bond - three electrons shared
Macromolecules • Large organic molecules. • Also called POLYMERS. • Made up of smaller “building blocks” called MONOMERS.
HO H HO H H2O HO H Answer:Dehydration Synthesis • Also called “condensation reaction” • Forms polymers by combining monomers by “removing water”.
HO H H2O HO H HO H Answer: Hydrolysis • Separates monomers by “adding water”
Macromolecules • FOUR MAIN CATEGORIES: 1) carbohydrates: fuel & building material 2) lipids: fats & oils 3) proteins: perform most cell functions 4) nucleic acids: information storage (Chap. 11) • Made up of nucleotides • DNA & RNA • Forms the genetic code
Carbohydrates • Carbohydrates are made of sugar molecules • Sugars contain carbon, hydrogen, and oxygen in the following ratio: • 1 carbon : 2 hydrogen : 1 oxygen
3 main types of carbohydrates: • Monosaccharide: one sugar unit • Ex: glucose, fructose, lactose • Disaccharide: two sugar units • Ex: Sucrose (glucose + fructose) • Ex: Galactose (glucose + lactose) • Polysaccharide: many sugar units; • Ex: Starch: found in plants (bread, tomatoes) • Ex: Glycogen: found in animal cells • Ex: Cellulose: found in cell wall of plants
Carbohydrates • Most carbohydrates are polar and hydrophilic • Hydrophilic: attracted to water molecules • Monosaccharides and disaccharides easily dissolve in water to form sugar solutions
Lipids • Lipids are not soluble in water. • They are nonpolar and hydrophobic do not mix with water • Lipids “store the most energy” • Examples: • Fats, oils • Phospholipids • Steroid hormones • 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)
O C-CH2-CH2-CH2-CH2-CH2-CH2-CH2-CH2-CH2-CH3 = H H-C----O H-C----O H-C----O H O C-CH2-CH2-CH2-CH2-CH2-CH2-CH2-CH2-CH2-CH3 = O C-CH2-CH2-CH2-CH fatty acids = =CH-CH2-CH2-CH2-CH2-CH3 glycerol Simplest Fats Triglycerides: composed of 1 glycerol and 3 fatty acids.
O C-CH2-CH2-CH2-CH2-CH2-CH2-CH2-CH2-CH2-CH3 = saturated O C-CH2-CH2-CH2-CH = unsaturated =CH-CH2-CH2-CH2-CH2-CH3 Fatty Acids There are two kinds of fatty acids: 1. Saturated fatty acids: no double bonds (bad) solid at room temperature, Ex: butter 2.Unsaturated fatty acids: at least 1 double bonds (good) liquid at room temperature, Ex: Fruits, olive oil
Steroids • Classified as lipids are hydrophobic • Differ from fats in structure & function • Some act as chemical signals or hormones estrogen and testosterone
Functions of Proteins • Form structures—hair, fur, muscles • Provide long-term nutrient storage • Circulate and defend the body against microorganisms (antibodies) • Act as chemical signals—hormones • Help control chemical reactions in cells—enzymes
Amino Acids (aa) aa1 aa2 aa3 aa4 aa5 aa6 Peptide Bonds Protein Structure • Proteins are polymers formed from monomers called amino acids. • Amino acids bonded together by peptide bonds (polypeptides). • There are 20 different kinds of amino acids.
Amino Acid Structure • Three of central carbon’s partners are the same in all of the 20 different amino acids 1. hydrogen atom 2. carboxyl group 3. amino group
Amino Acid Structure • Differences between one amino acid and another are due to the unique “R group” or side group that each one has • Each “R group” is responsible for a different chemical property for each amino acid
Protein Shape • Functional proteins consist of precisely twisted, coiled, and shaped polypeptides • Proteins cannot function correctly if shape is altered • Denaturation: loss of normal protein shape • Unfavorable changes in temperature, pH, or other environmental conditions may cause proteins to become denatured
Enzymes are proteins that speed up specific reactions in cells
Activation Energy • Activation energy: minimum energy required to start chemical reaction • Catalysts: compounds that speed up chemical reactions • Enzymes: proteins that act as catalysts for chemical reactions in organisms
How Enzymes Work ACTIVE SITE MODEL • Substrate: specific reactant acted on by an enzyme • Active site: specific region of the enzyme that the substrate fits into • Substrate binds to enzyme’s active site where the substrate undergoes a change