Chapter 3

1. www.nicholls.edu/biol-qcf Chapter 3 Biology Sixth Edition Raven/Johnson (c) The McGraw-Hill Companies, Inc.

2. The Chemistry of Carbon Organic molecules contain C and H Because carbon only has 4 electrons in its outer shell, it can attach to four separate molecules Organic molecules consisting of only C and H are called hydrocarbons.

3. Hydrocarbon chains can have functional groups that cause the macromolecule to behave in a certain way. Carboxyl Group: -COOH  -COO¯ + H+

5. Making and Breaking Macromolecules • Macromolecules (polymers) are formed from smaller building blocks called monomers. • Macromolecules are formed by dehydration synthesis (requires energy) • Macromolecule bonds are broken by hydrolysis (releases energy in bonds)

6. Energy must be used to build macromolecules. Energy is released when macromolecules are split.

7. Four Types of Organic Macromolecules • Proteins • Nucleic Acids • Lipids • Carbohydrates

8. Enzyme Catalyst Facilitate chemical reactions Defense Body’s hormone and immune system Transport Specific small molecules and ions Support Structural roles Motion Aid in muscle movement Regulation Intercellular messengers Protein Types and Function

9. Protein Building Blocks • Proteins are made of linked amino acids • Only 20 amino acids available • Sequence of amino acids are unique for each protein

10. COOH C H R NH2 Structure of Amino Acids (Acidic Group) (Hydrogen Group) (R or Functional Group) (Amino Group)

11. Five Groups of Amino Acids • Nonpolar • Polar • Aromatic • Ionizable • Special Structural Property

12. Contains –CH2 or –CH3 Contains –O or only H

13. Contains carbon ring that has alternating single and double bonds

14. Contains acids or bases

15. Special function

16. Amino acids are linked by peptide bonds: Dehydration synthesis

17. Primary Structure - Amino Acid Sequence Secondary Structure - Folding due to hydrogen bond Motifs – Characteristic secondary structure (   creates a fold or crease)

18. Driven into its tertiary structure by hydrophobic reactions with water, disulfide bonds, and other ionic and covalent bonds -remember: some amino acids are nonpolar. subunits Domain – structurally independent functional unit Two or more polypeptide chains associate to form a functional protein

19. Protein Structure Viewed at Six Levels • Amino acid sequence (primary structure) • Coils and sheets (secondary structure) • Folds or creases (motifs) • Three-dimensional shape (tertiary structure) • Functional units (domains) • Individual polypeptide subunits associated in quaternary structure

20. Chaperonins – proteins that help other proteins fold correctly

21. Primary structure determines tertiary structure!

22. Nucleic Acids • Nucleic acids are polymers of nucleotides. • Examples include Deoxyribonucleic Acid (DNA) and Ribonucleic Acid (RNA). All nucleotides have: 1.) nitrogenous base 2.) pentose sugar -deoxyribose -ribose 3.) phosphate group

23. Fig. 3.14 A chemical difference between DNA and RNA Fig. 3.15 Nucleotides (monomer) connected by phosphodiester bonds to form nucleic acid (polymer).

24. Hydrogen bonds between base pairs gives DNA its characteristic double-helix shape.

25. Purines always bond with a pyrimidine, and with DNA it is always: A-T; G-C H instead of CH3 Adenine Guanine Cytosine Thymine Uracil DNA vs RNA: RNA has Uracil instead of Thymine

26. DNA – double stranded, contains thymine, #2 C attached to H RNA – single stranded, contains uracil, #2 C attached to OH

27. Adenosine triphosphate Nucleotide bases also play an important part in other molecules crucial to life: ATP, NAD, and FAD.

28. Lipids- triglycerides, phospholipids, steroids Lipids serve as long-term energy stores in cells, form membranes, and serve as hormones and insulation. Lipids contain more energy per gram than any other biological molecule. Lipids are nonpolar, thus they do not dissolve in water (hydrophobic). All lipids are insoluble in water!!

29. Structure of Triglycerides Fatty Acids: long chains of hydrocarbons with an acidic functional group –COOH Saturated: no double bonds between carbons, “saturated with hydrogen”, higher melting point than unsaturated Unsaturated: has one or more double bonds between carbons saturated Dehydration or unsaturated functional group –COOH

30. Solids (butter) at room temperature; fatty acids can align close to each other Liquids (corn oil) at room temperature; double bonds prevent fatty acids from aligning close to each other

31. Non- Polar end Polar end Phosphate Phospholipids consist of: Glycerol 2 Fatty acids Phosphate group

32. Contains a phosphate group Cellular membranes

33. Terpenes – long chain lipids; components of many biologically important pigments All steroids characteristically have four carbon rings.

34. Carbohydrates Carbohydrates contain C, H, and O and serve as quick energy and short-term energy storage. Monomers of carbohydrates are the monosaccharides (simple sugars)

35. 6-Carbon sugars – primary energy storage

36. Empirical formula for a 6-C sugar: C6H12O6 Glucose is metabolized by cellular respiration

37. ‘double sugars’ – important in sugar transport Dehydration synthesis – consumes energy Hydrolysis splits the disaccharides and releases energy

38. Same empirical formula (C6H1206)– different arrangement. Your taste buds can taste the difference!

39. Energy storage for plants Energy storage for animals

40. Structural polysaccharide – chief component of plant cell walls Modified form of cellulose with a nitrogen group added to the glucose units. Structural building material in insects, many fungi, and certain other organisms.

42. The End.