Section 2 Molecules of Life

1. Section 2 Molecules of Life Pg. 55

2. 4 molecules of life Carbohydrates (pink background slides) Proteins (blue background slides) Lipids (green background slides) Nucleic Acids (grey background) Click a molecule above to jump to that slide

3. Carbohydrates Organic compounds composed of carbon, hydrogen, and oxygen in a ratio of 1:2:1 Carbohydrates can exist as 1) monosaccharides(simple sugar) 2) disaccharides (double sugar) 3) polysaccharides (“many” sugars)

4. Glucose is a very important sugar to living things. Glucose, a type of carbohydrate, is the most important source of energy for our cells.

5. Monosaccharides- simple sugars H2O Glucose Fructose Galactose They can be combined to form a disaccharide by a ? reaction. CONDENSATION

6. Isomers- same formula but slightly different structure Prove it: Count the carbons (C) Oxygen (O) Hydrogen (H) C6H12O6 glucose

7. Polysaccharides & examples Composed of three or more monosaccharides especially glucose 1) glycogen 2) starch 3) cellulose Animals storeglucose as glycogen.

8. Plants store glucose as starch. cellulose Another large polysaccharide is cellulose

9. Proteins Compounds made of carbon, hydrogen, oxygen, and nitrogen

10. Proteins make up hair, skin, muscles, enzymes, and horns

11. Amino acids- the building block or subunit of proteins There are 20 amino acids and they are linked together by peptide bonds to form proteins. A ? reaction is the process that links them together. CONDENSATION

12. A peptide bond forms between 2 amino acids… The peptide bond forms between the C, H, N, O.

13. Amino acids are linked together to form a protein chain Almost all of them end in ‘ine’ The chain then folds into various shapes. alanine arginine asparagine aspartic acid cysteine glutamic acid glutamine glycine histidine hydroxyproline isoleucine leucine lysine methionine phenylalanine proline serine threonine tryptophan tyrosine valine

14. The Structure of One Amino Acid Each amino acid has a different “R” group. The “R” group gives different proteins different shapes and therefore different functions.

15. Enzymes are Protein Enzymes are molecules that catalyze reactions in living systems They make reactions go faster by reducing activation energy They lower activation energy by linking to a substrate and weakening the bonds within that substrate

16. Induced Fit Model (shows how enzymes work) See it in action click here!

17. Forming two products with from one substrate

18. There are 3 basic steps of enzyme action: 1) A substrate attaches to the active site of an enzyme. 2) The enzyme changes shape weakening the bonds of the substrate. 3) The substrate turns into something different (products) and is released from the enzyme.

19. About enzymes They may not work if the temperature or the pH is not right. • Enzymes are very specific for the reactions they control. • Without enzymes, reactions would go too slowly to support life processes.

20. Lipids • Large nonpolar organic molecules • Highest energy storage of all organic molecules • 5 types of lipids • Fatty acids • Triglycerides • Phospolipids • Waxes • Steroids

21. Fatty Acids • Long carbon chains ended with a carboxyl group COOH • This is a polar end • It is water loving – called hydrophillic • Other end is the long chain of hydrocarbons (so named for C-H bonds) • It is water fearing – called hydrophobic

22. Fatty acid structures Hydrophillic carboxyl end Hydrophobic hydrocarbon end There are only single C bonds THIS IS SATURATED Notice the double bonded C chain, C was one H short so it double bonded to the next C – THIS IS CALLED UNSATURATED

23. Double C bonds cause bends in the tail of the Fatty acids

24. Triglycerides Three fatty acid molecules bonded to an alcohol glycerol These can be saturated (like shown) or unsaturated

25. Examples of triglycerides Saturated unsaturated • Typically solid at room temp • Butter fats in red meats • Typically liquids at room temp • Inside plant seeds as energy to help the seed grow

26. phospolipids Two fatty acid attached to a glycerol These make up the lipid bilayer of cell membranes

27. Waxes and steroids When only one fatty acid if attached to a glycerol Steroids – four fused carbon rings. Often they make up animal hormones like testosterone, cholesterol etc

28. Nucleic Acids • These organic molecules store and transfer genetic information • Two major types • Ribonucleic acid (RNA) • Stores/transfers information in DNA • Manufactures proteins • Acts as an enzyme • Deoxyribonucleic acid (DNA) • Determines the characteristics of an organism • Both are made of polymers called nucleotides