4 Types of Organic molecules found in living organisms
Carbohydrates, lipids, proteins, nucleic acids
Organic Molecule
Molecules that are carbon based
Hydrocarbon
The 4 molecules found in living organisms, called this due to the presence of carbon and hydrogen.
Polymer
Large macromolecules composed of smallermonomer subunits.
Dehydration Synthesis Reaction
How polymers are made from monomers. Result in the loss of water, which creates strong covalent bonds between monomers.
Hydrolysis
Reaction used to break polymers into their monomer subunit via the addition of water.
Reagents
Molecule that will react with an organic molecule in a specific way, usually by change of color.
Positive control
Substance or solution that contains the target molecule. Shows how a positive result should look.
Negative Control
Substance or solution that does not contain the target molecule. Shows what a negative result should look like.
Carbohydrates
Usually consist of carbon:hydrogen:oxygen in a 1:2:1 ratio. Important for energy storage and cell structure.
Monosaccharide
monomer unit; used as energy source (glucose, fructose)
Disaccharide
2 monosaccharides bonded together; used in transport within organisms (sucrose, lactose, maltose)
Polysaccharide
3 or more monosaccharides bonded together;energy storage (starch, glycogen) or structural components (cellulose)
Reduction
The gain of an electron
Oxidation
The loss of an electron. Oxidation and reduction reactions are always coupled, as one atoms reduces and the other oxidizes.
Reducing agent
causes the reduction (gain of electrons) of another molecule by losing electrons itself.
Benedict's reagent
Reagent used to test for reducing sugars (monosaccharides and most disaccharides, except sucrose. Reagent in oxidized form is blue (no reaction). When reduced (reacts with reducing sugar), will turn green, to yellow, to red and formprecipitate. The greater amount of reducing sugar, the greater the color progression and the moreprecipitation occurs. Sugars must be in linear form, with free aldehyde, toreact with Benedict's reagent. Heat is requiredto open ring (boiling bath for 1 minute). Too much heat will cause hydrolysis; false positive withpolysaccharides!
Starch
Starches are insoluble polysaccharides composed ofglucose monomers. They are the energy storage molecule of plants.
Two Main Forms of Starch
Amylose - very long chains, few branches. Forms an insoluble coil in water.Amylopectin - branched molecules.
Iodine reagent
Test for starch. When added to amylose, complex of iodine reagent and coiled amylose produce deep blue-black color. Iodine does not react like this with other polysacharides.
Lipids
Loosely defined group of molecules withone main chemical characteristic. Insoluble in water. High proportion of nonpolar C—H bondscauses the molecule to be hydrophobic. Fats, oils, waxes, and even some vitamins
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Saturated fatty acid
Contain all single covalent bonds; giving them a linear structure.
Polyunsaturated
Double carbon-carbon covalent bonds that kink the molecule.
Triglycerides
Composed of 1 glycerol and 3 fatty acids
Fatty Acids
Fatty acids- Need not be identical- Chain length varies- Saturated - no double bonds between carbonatoms• Higher melting point, animal origin- Unsaturated - 1 or more double bonds• Low melting point, plant origin
Sudan IV
Is a nonpolar red dye that only dissolves in other nonpolar solvents. Based on soluble -When soluble, gives a deep reddish color. Tests for the presence of oils.
Greasy Spot Test
- Leaves clearing spot on paper (if water, thenwill evaporate and disappear). If it dries the residue is aqueous. If residue is left behind, it is most likely a lipid.
Detergents
- Non-polar and polar regions in the samemolecule; can form emulsion to dissolve oilsin water. Are amphipathic.
Proteins
The most abundant of the four organic molecules found in cells. Functions include: catalyzing chemical reactions (enzymes), structure, transport, host defense and regulation of important cell functions.Amino acids are the monomers• Amino acid structure- Central carbon atom- Amino group- Carboxyl group- Single hydrogen- Variable R groupAmino acids joined by dehydrationsynthesis.
Biuret Reagent
Test for proteins that reacts with peptide bonds. Blue when not reacted with proteins. When interacts with peptide bonds, produces a purple or violet color. The amount of color/intensity is proportional to the number of peptide bonds present. Amino acids will not give a positive Biuret test (no peptide bonds.)
Nucleic Acids
Monomers - nucleotides- sugar + phosphate + nitrogenous base- sugar is deoxyribose in DNA or ribose in RNA- Nitrogenous bases include• Purines: adenine and guanine• Pyrimidines: thymine, cytosine, uracil- Nucleotides connected by phosphodiesterbonds
Test for DNA
Dische diphenylamine reagent- Under acidic conditions, diphenylaminereagent reacts with DNA (at the sugar in thenucleotides) to form a blue color.- RNA will not give a positive diphenylaminereaction (depends on having only hydrogen atcarbon 2 position of deoxyribose)