Carbohydrates Contain C, H, O atoms (1:2:1 ratio) # Carbon atoms = # Oxygen atoms Fx: 1. ENERGY STORAGE…WHY?? The C-H bonds store energy. When an organism requires an energy source, C-H bonds are the ones most often broken. This results in the release of stored energy. 2. Structural Support!!! Comprise 1-2% of a cells mass 2 types: simple carbohydrates complex carbohydrates
Simple Carbohydrates Monosaccharide Simple sugar Consists of one subunit; smallest carbs Ex. Glucose (C 6 H 12 O 6 ) Also, fructose, ribose, deoxyribose Disaccharide Result of linkage of two monosaccharides Ex. Sucrose, lactose, maltose
Complex Carbohydrates Polysaccharides Long chain polymers of sugars Preferred form of energy storage – Plants: starch = glucose polysaccharide that plants use to store energy – Animals: glycogen = highly insoluble macromolecule formed of glucose and polysaccharides that serves as stored energy
Lipids Contain C, H, and O Fx: 1. Sx makeup of membranes 2. Store energy, long term 3. Hormonal activities Hydrophobic (held together by non-polar covalent bonds) Contains MORE energy-rich C-H bonds than carbs Types include: neutral fats, phospholipids, steroids, carotenoids, waxes – Neutral fats:most abundant type of lipid 3 Fatty Acids + glycerol Simplest lipid = fatty acid
Lipids Triglycerides (Neutral Fat) Fats are synthesized from 2 components: 1. Fatty acid: long chain C and H atoms ending in a COOH group 2. Glycerol: a three C molecule; note, glycerol is an alcohol Glycerol forms a backbone to which 3 fatty acids are attached via a dehydration reaction fat molecule Provides long term energy storage, insulation
Protein Comprises 10-30% cell mass Contains C, H, O, N, S (sometimes) Fx: 1. enzymes 2. structural roles (collagen, keratin) All proteins are a long polymer chain of amino acid subunits – small molecules, 20 total – all 20 have a basic structure of a central carbon atom to which the 4 following are attached: hydrogen atom amino group (-NH2) carboxyl group (-COOH) an “R” group
How to make a protein Link specific amino acids together at functional groups – Functional group = the portion of a molecule that takes part in a chemical reaction – Peptide bond = covalent bond that links 2 amino acids together – Polypeptides = long chains of amino acids liked by peptide bonds
Nucleic Acids DNA and RNA DNA (deoxyribonucleic acid) Possible nucleotides: Adenine, Guanine, Cytosine, THYMINE Structure: 2 nucleotide strands = double helix RNA (ribonucleic acid) Possible nucleotides: Adenine, Guanine, Cytosine, URACIL Long, single strand
Part A: Testing for Carbohydrates: Reducing Sugars Benedict’s Reagent: tests for reducing sugars present in carbohydrates Reducing sugar = any sugar that when in solution forms an aldehyde or ketone, i.e. monosaccharides (non- locked) How?? Benedict’s Reagent contains blue copper (II) ions (Cu 2+ ) that are reduced to copper (I) ions (Cu + ). The Cu + ions are precipitated in water as red copper (I) oxide. Glucose Gluconic Acid
Part A: Reducing Sugars Test glucose, sucrose and starch solutions in the presence of Benedict’s reagent to detect presence of reducing sugars GlucoseSucroseStarch
Part B: Testing for Carbohydrates: Starch Iodine reacts with starch producing a dark blue, black color How?? Starch is a coiled polysaccharide. When iodine is introduced, it forms a linear molecule and inserts into the starch coil thus resulting in a color change Test starch presence in glucose, sucrose and starch solutions as well as potato slices
Part C: Testing for proteins, Biuret Test Biuret test detects protein by copper sulfate reacting with peptide bonds producing a violet color
Part C: Testing for proteins, Biuret Test Test for protein in honey solution, corn oil and egg white solution
Part D: Testing for Nucleic Acids, Dische Diphenylamine Test Diphenylamine Reagent reacts with the deoxyribose sugar in DNA producing a blue color when heated
Part E: Testing for Lipids, Sudan III Test Takes advantage of the fact that lipids are NONPOLAR compounds – They DO NOT dissolve in water. Why? – They DO dissolve in ether, a nonpolar solvent Sudan III dye is made with ether as is its solvent Note: nonlipid substances will NOT dissolve in Sudan III, rather, they will form two distinct layers in a test tube Test honey, corn oil and egg white for the presence of lipids DO NOT POUR SUDAN III DOWN THE DRAIN!!!
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