1. Proteins, Enzymes and Nucleic Acids

2. Structure of a Fat molecule

3. Proteins

4. Protein Functions

5. Proteins-1 Proteins are made of amino acids There are 20 different amino acids found in living things Amino acids have –An amine group –A carboxyl group –Both are attached to the end carbon of a carbon chain

6. Amino Acids

8. Connecting Amino Acids Dehydration synthesis reaction resulting in a polypeptide

9. Primary Structure of a Protein

10. Secondary Structure of a Protein

11. Tertiary Structure of a Protein

12. Quaternary Structure of a Protein

13. Protein Structure

14. Proteins & Evolutionary Relationships

15. Enzymes

16. Enzyme Characteristics-1 All enzymes are proteins Most enzymes are named after their substrate and end in –ase Enzymes are specific- they work on only one substrate Enzymes must physically fit together with their substrate- this is what makes them so specific Enzymes have an active site- this is where the reaction takes place

17. Enzyme reaction

18. Enzyme Characteristics Enzymes are denatured by high temperatures and by a pH that is too high or too low, relative to their optimal pH Denatured enzymes lose their shape, so they no longer fit with their substrate

19. How Enzymes Work Enzymes are catalysts– they speed up reactions –They are not consumed in the reaction –They are not changed in any way at the end of the reaction –They can work in small quantities, because they can be used over and over –They do NOT make reactions occur that would not occur by themselves- they merely speed them up Lock and Key Hypothesis Induced Fit Hypothesis

21. Some substances can make enzymes inactive

22. Metabolic Control Competitive inhibitors- block the substrate from entering active sites Noncompetitive inhibitors- impede enzymatic reactions by binding to another part of the enzyme which causes the enzyme to change shape, making the active site unreceptive to substrate. Allosteric regulation- similar to reversible noncompetitive inhibitors. –Allosteric site- a receptor site on the enzyme remote from the active site –Causes inhibition or stimulation of enzyme activity –Enzyme activity changes due to fluctuating concentrations of the regulators.

23. Energy in reactions Potential energy- –stored energy –Example: Energy in the chemical bonds Kinetic energy –Energy of motion or work –Example: Energy used to make chemical bonds

24. Endergonic/Exergonic Reactions

25. Activation energy

26. Activation energy of an enzymatic reaction

27. Enzyme Helpers- necessary for catalysis Cofactors- nonprotein helpers –May be bound tightly to the active site –May bind loosely and reversibly along with the substrate –Some are inorganic: zinc, iron, copper Coenzyme- protein helper –Most vitamins are coenzymes or –Some vitamins are raw materials from which coenzymes are made

28. Nucleic Acids

29. Nucleic Acid Structure Nucleic acids are made of Nucleotides Nucleotides are made of: –A Phosphate group –A Sugar: either ribose or deoxyribose –A Base: A, T, G, C, U A= adenine T= thymine G= guanine C= cytosine U= uracil

32. Nucleic Acids- DNA & RNA There are only two nucleic acids: –DNA: deoxyribonucleic acid –RNA: ribonucleic acid Functions: control cell function and heredity –DNA makes RNA –RNA makes proteins

33. Comparison of DNA and RNA Structure DNARNA SugardeoxyriboseRibose BasesATGCAUGC StrandsDOUBLE helix Single helix

34. Structure of one strand of a DNA molecule

35. Structure of DNA