1. Chapter 2: Chemicals of Life

2. A. Bonding 1. Covalent Bonds – 2 or more atoms share electrons to form a molecule – No net charge due to equal number of + and – – Ex. water

3. Properties of Water Covalent bonding vs. Hydrogen bonding Covalent Bond Hydrogen Bond

4. A. Bonding 2. Hydrogen Bonds Weak bond between polar molecules

5. A. BondingBonding 3. Ionic Bonds – Gained or lost one or more electrons – Charged due to unequal number of electrons or protons – Ex. NaCl

6. B. Properties of Water a.Water heats slow b.Retains heat longer c.Helps maintain homeostasis 1. High Heat Capacity

7. B. Properties of Water Water is the solvent of Life! Solute – substance dissolved in a solvent to form a solution Solvent – fluid that dissolves solutes Example: Ice Tea – water is the solvent and tea and sugar the solutes 2. Universal Solvent

8. B. Properties of Water a. cohesion = water attracted to other water molecules because of polar properties ex. Forms drops or film surface tension = water is pulled together creating the smallest surface area possible b. adhesion = water attracted to other materials ex. Getting wet, capillary action 3. Cohesion, Adhesion and Surface Tension

9. B. Properties of Water 4. Capillary Action = Water molecules move due to adhesive and cohesive properties as a result of the original adhesion. Ex: Think water in a straw Ex: Water moves through trees this way

10. B. Properties of Water 5. Water is a polar molecule. – Many substances will dissolve – Non-polar molecules will not dissolve

11. C. Classes of Organic Molecules: What are the four classes of organic molecules? Carbohydrates Lipids Proteins Nucleic Acids

12. 1. Carbohydrates Sugars Carbo = carbon, hydrate = water; Oxygen Functions: Store energy in chemical bonds Glucose is the most common monosaccharide – Monosaccharides – Disaccharides – Polyshaccharides

13. 1. Carbohydrates Benedicts Test

14. 1. Carbohydrates Iodine – Starch test

15. 2. Lipids Structure: Greasy or oily nonpolar compounds Functions: Energy storage membrane structure Protecting against drying out. Insulating against cold. Absorbing shocks.

16. 2. Lipids Saturated and Unsaturated Fats Unsaturated fats : – liquid at room temp – one or more double bonds between carbons in the fatty acids allows for “kinks” in the tails – most plant fats Saturated fats: – have only single C-C bonds in fatty acid tails – solid at room temp – most animal fats

17. 2. Lipids. Phospholipids Structure: Glycerol + 2 fatty acids + phosphate group. Function: Main structural component of membranes, where they arrange in bilayers.

18. 3. Proteins Structure: Polypeptide chains Consist of peptide bonds between 20 possible amino acids Have a 3 dimensional globular shape

19. 3. Functions of Proteins Enzymes speed up a chemical reaction Structural materials – keratin (the protein found in hair and nails) – collagen (the protein found in connective tissue) Specific carriers – – Carry materials across cell membrane, carry oxygen in blood

20. 3. Proteins: Structure of Amino Acid – Hydrogen – Amino group – Carboxyl (acid) group – Variable R group specific to each amino acid

21. 4. Nucleic Acids Two kinds: – DNA: double stranded can self replicate makes up genes which code for proteins is passed from one generation to another – RNA: single stranded functions in actual synthesis of proteins coded for by DNA is made from the DNA template molecule