Carbon Chemistry - John A Ferguson Senior High School：碳化学-约翰弗格森高中

1、The Molecular Building Blocks of Life Objectives3.2.1 Distinguish between organic and inorganic compounds.3.2.2 Recognize the physical differences between the macromolecules that are the building blocks of life.3.2.3 State the uses for carbohydrates, lipids, nucleic acids, and proteinsThe Importance

2、 of carbonCells are 70-95% water, the remainder is mostly carbon-based compounds.Proteins, DNA, carbohydrates, & lipids distinguish living matter from inorganic material; all are composed of carbon atoms bonded to each other & to atoms of other elements, including H, O, N, S, & P (percentages are qu

3、ite uniform in all life).oxygen (65 percent); carbon (18 percent); hydrogen (10 percent); nitrogen (3 percent); phosphorus (1 percent); andsulfur (0.2 percent).Organic chemistryOrganic chemistry is the study of carbon compounds.Produced not only in biological processes, they can also be synthesized

4、by non-living reactions.Organic compounds range from simple CH4 (below), to complex molecules, like proteins & DNA (at right).Organic chemistryOrganic compounds contain carbon & hydrogen together!CH4 methane, C8H18 octane, C6H12O6 glucose If a carbon compound is not accompanied by hydrogen, it is co

5、nsidered inorganic.CO2 inorganic (no H)CCl4 inorganic (no H)CoCl2 inorganic (no C)CaHPO4 inorganic (no C)HCl inorganic (no C)Dont be fooled!Atomic carbonCarbon atoms are the most versatile building blocks of molecules.With a total of 6 e-, a C atom has 2 in the first shell and 4 in the second shell.

6、Only outer shell elec-trons are involved in chemical reactions, soC has 4 e- to share (itmakes 4 attachments).Carbon is tetravalentCarbon shares 4 electrons.Note C makes 4 attachments, but H makes only 1.Carbon is tetravalentCarbon can bond with itself; there are still always 4 attachments (4 bonds)

7、.Ethylene (-ene signifies a double bond)Isomers of butyne (-yne signifies a triple bond); still a total of four bonds on each carbon atom.Carbon is tetravalentThe e- configuration of C lets it form covalent bonds with many different elements.In carbon dioxide, one C atom forms 2 double bonds with 2

8、different O atoms. The structural formula, O = C = O, shows that each atom has completed its valence shells. CO2 is the source for all organic molecules in organisms via the process of photosynthesis.Carbon is tetravalentAnother example:Urea, CO(NH2)2, is a simple organic molecule in which each atom

9、 has enough covalent bonds to complete its valence shell.H needs 1 e-O needs 2 e-N needs 3 e-HydrocarbonsHydrocarbons: organic molecules that consist of only C & H.Hydrocarbons are the major component of petroleum.Petroleum is a fossil fuel because it consists of the partially decomposed remains of

10、organisms that lived millions of years ago.Carbon-based life formsLife on Earth is based on carbon.Four types of carbon molecules are building blocks.CarbohydratesLipidsNucleic acidsProteinsCarbohydratesFunction: fuel and building material; made of equal amounts of C+H2O (carbon hydrates). #H = 2x #

11、O.Monosaccharides (simple sugars).Ex: glucoseDisaccharides (double sugars). Ex: sucrosePolysaccharides are long chains of monosaccharides.Ex: starch (in flour)CarbohydratesMonosaccharides have molecular formulas that are some multiple of CH2O. Ex: glucose - C6H12O6. (#H = 2x #O) Most names for sugar

12、s end in ose: glucose, ribose.Disaccharides form from monosaccharides by dehydration (an H and an OH are removed).Glucose + glucose produces maltose (and water)CarbohydratesPolysaccharides are polymers of hundreds to thousands of monosaccharides.Function in energy storage (used as needed).Ex: starch

13、 (plants) & glycogen (in animals livers)Function as strong building materials. Ex: cellulose LipidsLipids are hydrophobic dont mix with water.In a triglyceride, three fatty acids (same or different) are joined to glycerol. Made of C, H, & O, but the H:O ratio is much greater than 2:1.LipidsA saturat

14、ed fat has no carbon-carbon double bonds, and it is straight. They pack together solid at room temperature.Unsaturated fats have one or more carbon-carbon double bonds, and they bend. They cant get close to each other, so they are liquid at room temperature.LipidsSaturated fats come from animal prod

15、ucts.Ex: butter, lardA diet rich in saturated fats may contribute to cardiovascular disease (heart attack, stroke) through plaque deposits in arteries; obesity, diabetes.LipidsUnsaturated fats come from plant & fish products.Ex: olive oil, corn oil, safflower oil, fish oils.Generally considered heal

16、thier for the heart.LipidsFunctions of lipidsNutrition: 1g of fat contains twice as much energy as 1g of carbohydrate.Protection: cushions vital organs & insulates them.This subcutaneous layer is especially thick in whales, seals, and most other marine mammals.LipidsFunctions of lipidsPhospholipids:

17、 major components of cell membranes.Have two fatty acids attached to glycerol and a phosphate group at the third position.LipidsFunctions of lipidsWaxes reduce water loss by plants.Carnauba waxSteroidsCholesterol is a component in animal cell membrane.Many steroids are hormones.Nucleic acidsAll mole

18、cules of the body are programmed by a genetic code in the organisms DNA, a polymer of nucleic acids. Nucleic acids store and transmit hereditary in-formation.Made of C, H, O, N, & P.A nucleic acidNucleic acidsThere are two types of nucleic acid polymers: Ribonucleic acid (RNA)Single-stranded.Contain

19、s adenine, guanine, cytosine,and uracil.Sugar is ribose.Deoxyribonucleic acid (DNA)Double stranded.Contains adenine, guanine, cytosine, and thymine.Sugar is deoxyribose.ProteinsHumans have at least 30,000 different proteins, each with a unique structure and function.Functions include structural supp

20、ort, storage, transport of materials, intercellular signaling, movement, and defense.Enzymes are one class of proteins that regulate metabolism by moderating chemical reactions. All proteins are 3 dimensional.All are constructed from the same set of 20 monomers, called amino acids.All are made of C,

21、 H, O, and N (2 also contain S).ProteinsAmino acids are joined by dehydration; the resulting covalent bond is called a peptide bond.Polymers of amino acids are called polypeptides.ProteinsA proteins function depends on its precise twisting, folding, and coiling into a unique shape. The order of amin

22、o acids determines what the three-dimensional shape will be.Folding of a protein occurs spontaneously: an emergentproperty resulting from itsspecific molecular order.ProteinsIn individuals with sickle cell disease, abnormal hemoglobins develop because of a single amino acid substitution.ProteinsFibr

23、ous proteins are long, insoluble molecules .For movement (muscle fibers);For structure and support. Collagen in skin.Cartilage connects tissues. Keratin is found in hair, horns, wool, nails, and feathers.ProteinsGlobular proteins are soluble and form compact spheroidal molecules in water. Antibodies for immunity.Enzymes are involved in chemical reactions - meta