Chapter 6.3 Life Substances

1. Chapter 6.3Life Substances

2. The role of carbon in organisms • Carbon atoms have four electrons available for bonding in their outer most energy level • Stable Carbon formation = 4 covalent bonds • Carbon can bond with other elements & with other carbon atoms • Single Bonds- covalent bonds formed w/2 electrons shared btwn atoms • Represented by • Double Bonds- covalent bonds formed w/4 electrons shared btwn atoms • Represented by • Triple Bonds- covalent bonds formed w/6 electrons shared btwn atoms • Represented by

3. The role of carbon in organisms • Carbon atoms bond to each other and can form: • Straight chains • Branched chains • Rings • Chains or rings can have almost any # of carbons or other elements on them • Many Carbon formations = lots of carbon structures possible • Cmpds with same chemical formula can have different 3-D structures

4. The role of carbon in organisms • Isomers-compounds with same chemical formula but different 3-dimensional structures • Draw Glucose & Fructose-Note the same chemical formula, different structures • Carbon cmpds vary in size • Biomolecules –large organic cmpds • Ex/Proteins, Fats, Nucleic Acid, Carbohydrates

5. The role of carbon in organisms • Polymer-def- a large molecule formed when many smaller molecules bond together • How are Polymers formed? • Condensation Rxn • How are Polymers broken down? • Hydrolysis Rxn

6. The structure of Carbohydrates • Carbohydrates- a biomolecule composed of carbon, hydrogen, and oxygen with a ratio of 2H : 1 O : 1 C • Monosaccharide- a simple sugar • Ex/ Glucose & fructose • Disaccharide-a two sugar carbohydrate • How does a disaccharide form? • Ex/Sucrose (table sugar) -formed when glucose & fructose combine via condensation rxn

7. The structure of Carbohydrates • Polysaccharides = Largest carbohydrate molecules composed of many monosaccharids • Ex/Polysaccharide Examples • Starch-consist of branched chains of glucose units • Used as energy storage by plant cells and as food reservoirs in seeds & bulbs • Glycogen-consists of highly branched glucose polymer • Used by mammals to store energy in the liver • Cellulose-consists of long chains of glucose units that are linked together in a chain-link fence arrangement. • Used to form cell walls of plants and gives plants structural support

8. The structure of Lipids • Lipids-def-pg.160-large biomolecules that are made mostly of carbon and hydrogen with sm. Amt of oxygen • Ex/ fats, oils, waxes, & steroids • Insoluble in water (meaning they don’t dissolve in water)-b/c these molecules are nonpolar &  are not attracted by water molecules • Lipids generally contain: • 3 Fatty acids (long chains of carbon&hydrogen) • 1 glycerol molecule

9. The structure of Lipids • Types of Fatty Acids • Saturated-each carbon in the chain bonded to 1 other carbon by single bonds • Unsaturated- each carbon in the chain is bonded by a double bond • Polyunsaturated-fatty acids with more than one double bond

10. The structure of Lipids • Importance of Lipids: • Needed for propering fxn’ing of org • Cells use it for energy storage • Cells use it for insulation & protective coverings • Lipids major component of cell membrane (phospholipids)

11. The structure of Nucleic Acids • Nucleic acid-def-pg.163-a complex biomolecule that stores cellular information in the form of a code. • Nucleotides-def-pg.163-nucleic acids are polymers made up of smaller subunits called nucleotides which consists of the following elements: • Carbon -Oxygen • Hydrogen -Nitrogen • Phosphorous • Parts of a Nucleotide: • Nitrogenous base • Simple sugar • Phosphate grp

12. The structure of Nucleic Acids • DNA-def-pg.163- Deoxyribonucleic acid-master copy of an organism’s information code • RNA-def-pg.163-Ribonucleic acid, nucleic acid that forms a copy of DNA for use in making proteins

13. The Structure of Proteins • Proteins are essential to all life • Protein Components • Proteins-def-pg.160- a lrg, complex polymer that is composed of H2, O2, N2 & S. • Amino acids-def-pg.161- Basic building blocks of proteins = amino acids (A.A.) • 20 common A.A.  various diff combos can = thousands of proteins

14. The Structure of Proteins • How are A.A.s linked together? • –H from the amino grp & -OH grp from the hydroxyl grp are removed to form a peptide bond • –H & -OH come together to form a water molecule • Peptide bond-def-pg.161-the covalent bonds that are formed btwn A.A.s • Video-hippocampus video • http://www.hippocampus.org/homework-help/Biology/Biomolecules_Structure%20and%20Function%20of%20Proteins.html

15. The Structure of Proteins • Protein Structures & Fxns: • Protein Structure • Proteins come in lrg varieties of shapes & sizes • A.A. sequence & # that make up protein are imp in determining a protein’s shape • 3-D shape of protein is imp to a proteins’ fxn • Proteins imp in: • Contracting of muscle tissue • Transporting O2 in bloodstream • Providing immunity • Regulating other proteins • Carrying out chemical rxns & metabolism (enzymes) • Provide structure for tissue & organs

16. The Structure of Proteins • ALL ENZYMES ARE PROTEINS BUT NOT ALL PROTEINS ARE ENZYMES • Enzyme-def-pg161- a protein that changes the rate of a chemical rxn • Involved in nearly all metabolic processes. • Parts of the Enzyme: • Substrates-reactants in an enzymatic rxn • Active sites-the small part of the enzyme where the substrate binds • Activity of enzyme depends on: • temperature • ionic conditions • pH of surroundings • concentration of enzyme

17. The Structure of Proteins • How enzymes work? Action of Enzymes • Enzymes act on a specific substrate • Each substrate fits into an active site (lock & key theory) • Enzyme may can shape a little to fit with substrate • Enzyme-substrate complex puts a stress on the substrate due to the binding of the substrate to the enzyme this facilitates the reaction • Once reaction is complete the products are released from the enzyme • Enzyme is unchanged and retains its original shape & can now carry out more enzymatic rxns-process repeats Video-Yahoo Videos-”how enzymes works”- www.zo.utexas.edu & Enzyme Animation