1. Chapter 2 Chemistry of Life

2. Points to ponder How are living things organized from atoms to molecules? What is pH and how is it important to living organisms? What are the four macromolecules found in living organisms? What are the structure (subunits) and function of these 4 macromolecules? How are proteins organized and how is their shape important to their function? How are DNA similar and how are they different?

3. Building blocks from large to small Matter is anything that has weight and takes up space Elements are the basic building blocks of matter that cannot be broken down by chemical means Atoms are the smallest units of an element that retain the element’s physical and chemical properties. These bond together to form molecules 2.1 From atoms to molecules

4. Atoms Atom symbol Atomic mass Atomic number 2.1 From atoms to molecules

5. Subatomic particles of atoms Neutrons have a neutral charge Protons are positively charged Neutrons and protons make up the nucleus Electrons are electrically charged and orbit around the nucleus 2.1 From atoms to molecules

6. Isotopes Isotopes are atoms that have the same atomic number but a different atomic mass because the number of neutrons differ Radioactive isotopes are useful in dating old objects, imaging body organs and tissues through x-rays and killing cancer cells Radiation can be harmful by damaging cells and DNA and/or causing cancer 2.1 From atoms to molecules

7. Molecules: Are made of atoms that are bonded together Can be made of the same atom or different atoms 2.1 From atoms to molecules

8. Ionic bonds: Atoms in this type of bond donate or take on electrons Results in a stable outer shell Occurs between particles that are charged (ions) 2.1 From atoms to molecules

9. Covalent bonds: Atoms in this type of bond share electrons Results in a stable outer shell 2.1 From atoms to molecules

10. Polarity A polar covalent bond occurs when a shared pair of electrons is attracted more strongly to one of the atoms.

11. Why polarity is important? The rule for determining if a mixture becomes a solution is that polar molecules will mix to form solutions and non-polar molecules will form solutions, but a polar and non-polar combination will not form a solution. Water is a polar molecule and oil is a non-polar molecule. Thus they won't form a solution. On the other hand, since alcohol is a polar molecule, it will form a solution with water.

12. What are the properties of water? Liquid at room temperature Liquid water does not change temperature quickly High heat of vaporization Frozen water is less dense than liquid water Molecules of water cling together A solvent for polar molecules 2.2 Water and living things

13. What bond holds water molecules together? Hydrogen bonds occur between a hydrogen in a covalent bond and a negatively charged atom These are relatively weak bonds 2.2 Water and living things

14. Acids and bases Acids are substances that dissociate and release hydrogen atoms Bases are substances that take up hydrogen atoms or release hydroxyl ions 2.2 Water and living things

15. What is the pH scale? A measure of hydrogen ion concentration Working scale is between 0 and 14 with 7 being neutral A pH below 7 is acidic and above 7 is basic The concentration of ions between each whole number is a factor of 10 2.2 Water and living things

16. Looking at the pH scale16 2.2 Water and living things

17. Buffer solutions A buffer solution is one which resists changes in pH when small quantities of an acid or an alkali are added to it.

18. How do buffer solutions work? A buffer solution has to contain things which will remove any hydrogen ions or hydroxide ions that you might add to it - otherwise the pH will change.

19. How do buffer solutions work? CH 3 COOH  CH 3 COO - + H + Adding base: CH 3 COOH + NaOH  CH 3 COONa + H 2 O Adding acid CH 3 COO + H +  CH 3 COOH

20. Making and breaking down organic molecules Dehydration reaction – the removal of water that allows subunits to link together into larger molecules Hydrolysis reaction – the addition of water that breaks larger molecules into their subunits 2.3 Molecules of life

21. How do we build and break down organic molecules? 2.3 Molecules of life

22. What organic molecules are found in living organisms? 1. Carbohydrates 2. Lipids 3. Proteins 4. Nucleic acids 2.3 Molecules of life

23. 1. What are carbohydrates? Made of subunits called monosaccharides Made of C, H and O in which the H and O atoms are in a 2:1 ratio Function as short and long-term energy storage Found as simple and complex forms 2.4 Carbohydrates

24. What are simple carbohydrates? Monosaccharide – 1 carbon ring as found in glucose Disaccharide – 2 carbon rings as found in maltose 2.4 Carbohydrates

25. What are complex carbohydrates? Polysaccharides made of many carbon rings Glycogen is the storage form in animals Starch is the storage form in plants 2.4 Carbohydrates

26. Health focus - Sugar: Sweet Poison? A Harvard study found a link between drinking more than one sugar-sweetened soda per day and diabetes American Heart Association found consuming sugar can increase triglycerides that may lead to heart disease Consuming refined sugar may decrease the ability of white blood cells to keep diseases at bay Intake of sugar may lead to withdrawal symptoms and cravings for sugar much like an alcoholic 2.4 Carbohydrates

27. 2. What are lipids? Molecules that do not dissolve in water Used as energy molecules Found in cell membranes Found as fats and oils, phospholipids and steroids 2.5 Lipids

28. How are fats and oils different? Fats Usually animal origin Solid at room temperature Function as long-term energy storage, insulation from heat loss and cushion for organs Oils Usually plant origin Liquid at room temperature 2.5 Lipids

29. What is the structure of fats and oils? A glycerol molecule and 3 fatty acid tails 2.5 Lipids

30. Understanding fats when reading a nutrition label Recommendation for total amount of fat for a 2,000 calorie diet is 65g Be sure to know how many servings there are A % DV of 5% or less is low and 20% or more is high Try to stay away from trans fats Would you eat the food on the right? Why or why not? 2.5 Lipids

31. What are steroids? A lipid Structure is four fused carbon rings Examples are cholesterol and sex hormones 2.5 Lipids

32. 3. What are proteins? Made of subunits called amino acids Important for diverse functions in the body including hormones, enzymes and transport Can denature, change in shape, that causes loss of function 2.6 Proteins

33. What do amino acids look like? 2.6 Proteins

34. What are the four levels of protein organization? Primary – the linear order of amino acids Secondary – localized folding into pleated sheets and helices Tertiary – the 3-D shape of the entire protein in space Quaternary – combination of more than one polypeptide All proteins have primary, secondary and tertiary structure, while only a few have quaternary structure 2.6 Proteins

35. What do the levels of organization look like? 2.6 Proteins

36. 4. What are nucleic acids? Made of nucleotide subunits Function in the cell to make proteins Includes RNA and DNA 2.7 Nucleic acids

37. What are the 3 parts of a nucleotide? 2.7 Nucleic acids

38. What are the five bases found in nucleotides? Adenine (A) and guanine (G) are double- ringed purines Cytosine (C), thymine (T) and uracil (U) are single-ringed pyrimidines In DNA A pairs with T and G pairs with C 2.7 Nucleic acids

39. Summary of DNA and RNA structural differences? DNA –Sugar is deoxyribose –Bases include A, T, C and G –Double stranded RNA –Sugar is ribose –Bases include A, U, C and G –Single stranded 2.7 Nucleic acids

40. Summary of the macromolecules