organic basis of life chapter 3. organic compounds carbon based molecules – readily form covalent...
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Organic Compounds
• Carbon based molecules– Readily form covalent bonds
• Review electron shell model
– Hydrocarbons are nonpolar, containing only C and H• Dependent upon
– Structural size • CH4, C6O12H6, CO2 different number of carbon atoms
– Shape • Can form chains, branches, or rings• Isomers: same chemical formula, but different atomic arrangement
– Functional group• Creates specific structural and functional properties
• Be able to recognize/identify each
• Other groups, but don’t need to know
Carbohydrates
Lipids
Proteins
DNA, ATP
Proteins
Functional Groups
Carbon
• Significant basis of all living organisms • Creates a large diversity of biological molecules
– 4 main classes*• Carbohydrates• Lipids• Proteins• Nucleic Acids
– Distinguishes living from nonliving matter• All these molecules are examples of emergent properties
* important to know the monomers, polymers, and examples
Building Organic Molecules• Monomers are universal or similar units in all forms
of life• Polymers are functional components of cells
– DNA is composed of 4 types of nucleotides• Variation based on arrangement
– Proteins are composed of 20 different amino acids (AA’s)• Variation distinguishes within and between species
Making and Breaking MacromoleculesDehydration reaction
• Links monomers• Loss of water for each
monomer added• Forms a covalent bond
Hydrolysis reaction
• Breaks polymers• Addition of water for
each broken bond
1 42
21
3
3 4
1
2
2 3
3
4
41
Carbohydrates
• Range from sugar in beverages to starch in foods• Basic composition
– CH2O (1:2:1 ratio) – Have hydroxyl and carbonyl group– End in ‘-ose’– Hydrophilic (means what?; why?)
• Types– Monosaccharides – Disaccharides – Polysaccharides
• Energy storage
Monosaccharides
• Simple sugars (monomers)– Glucose and fructose
• Isomers (means what?)• Fructose is sweeter
– Galactose• Main fuel for cells
– Unused get incorporated into more complex sugars
• Most 3-7 carbon atoms long
Disaccharides
• 2 monosaccharides joined by a glycosidic bond– Dehydration reaction
• Maltose– glucose + glucose– Whoppers©, malts, beer
• Sucrose– Glucose + fructose– Table sugar– Plant sap
• Lactose– galactose + glucose
Polysaccharides
• Insoluble fiber• Storage
– Glycogen in animals (short term)– Starch in plants
• Structure– Cellulose in plant cell walls
• Not always digestable
– Chitin in insect and crustacean exoskeletons• Protection and nutrients for animals• Surgical thread
Lipids• Not true polymers• Long term energy storage• Insoluble
– Salad dressing (o & v)– Bird feathers (repellent beads)
• 3 types– Triglycerides (fats)
• Saturated are solid at room temp– Animal fats
• Unsaturated are liquids at room temp– Plant fats (oils)
– Phospholipids– Steroids
• Sex hormones• Synthetic forms
Proteins
• Polypeptide chain with a specific shape– Polymer of 20 amino acids (AA’s)– Variation determines structure and function
• Multiple roles– Enzymes: speed chemical reactions, end in ‘-ase’– Structural: hair and connective tissue– Signal: hormones for communication
• Altered by denaturation– Changes in [salt], pH, or excessive heat– Danger of high fevers
Amino Acids
• Common structure varied by side chain (R)• Properties determined by R group
– Hydrophilic or hydrophobic– (+) or (-) charge
• Dehydration reaction joins AA’s– Forms peptide bonds– Dipeptide = 2 AA’s joined– Polypeptide = multiple AA’s
• Hydrolysis reverses– Eating meat
• All polypeptides are not proteins
Protein Structure• Primary (1°)
– Sequence of AA’s determined by DNA
• Secondary (2°)– Folds (β-pleated sheet) and coils
(α-helix) from H-bonding• Tertiaty (3°)
– 3D shape of polypeptide– Globular or fibrous
• Quartenary (4°)– 2+ associated polypeptide chains
• Single change can change shape which changes function
Nucleic AcidsDNA
• Genetic code• Nucleotides
– Deoxyribose sugar– Phosphate group– 4 nitrogenous bases
• Adenine (A)• Cytosine (C)• Guanine (G)• Thymine (T)
• Double stranded– Hydrogen bonds w/i
• A & T• C & G
RNA
• Protein synthesis• Nucleotides
– Ribose sugar– Phosphate group– 4 nitrogenous bases
• Adenine (A)• Cytosine (C)• Guanine (G)• Uracil (U)
• Single stranded– Hydrogen bonds similar
• A & U• C & G
Basis For Life and Individuality
• Primary structure of polypeptides is determined by genes, discrete units of inheritance
• Genes are sequences of DNA– DNA determined by organization of 4 nucleotides
• DNA RNA proteins (polypeptides)
– Central dogma of molecular biology• Genes are the blueprint for the living organism
seen
transcribed
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