1. Chapter 2: Chemistry of Life

2. Building Blocks of Matter
The basic unit of matter is the atom
Atoms are made of subatomic particles: protons (+), electrons (-), and neutrons
Protons and neutrons reside in the nucleus
Electrons move around in orbitals outside of the nucleus
Atoms of the same element but with different neutrons are isotopes
Carbon-12, Carbon-13, Radioactive Carbon- 14

3. Building Blocks of Matter
Two or more elements can combine to form compounds (H2O)
Ionic bonds hold a compound together by a transfer of an electron leading to charged elements (NaCl)
Covalent bonds involve sharing of electrons between elements (H2O)

4. Building Blocks of Life
Element – Substance that can’t be broken down into simpler chemical substances.
Carbon - the element of life as it can combine with other elements and with itself to form long complex structures. It must have 4 bonds.

5. Macromolecules Macromolecules – big molecules
Monomers – small subunits (building blocks) of large molecules, ex. Glucose is the monomer of starch, a polymer
Polymer- made of many molecules, ex. proteins, nucleic acids

6. Carbohydrates Main source of energy for living organisms (glucose)
Organisms store energy as complex carbohydrates called starches

7. Carbohydrates Monosaccharide – single sugar.
Polysaccharide – large molecules formed from monosaccharides.

8. Lipids
Composed predominately of carbon and hydrogen atoms (limited oxygen)
Includes fats, oils, waxes, steroids
Composed of glycerol and fatty acids

9. Lipids

10. Nucleic Acids Composed of monomers called nucleotides
Composed of 5-C sugar, phosphate group, and a nitrogenous base
Joined together to form nucleic acids: ribonucleic acid (RNA) and deoxyribonucleic acid (DNA)
Store and transmit hereditary (genetic) information

11. Nucleic Acids

12. Proteins Contain nitrogen, carbon, oxygen, and hydrogen
Monomer: amino acids
20 different amino acids are found in nature, leads to significant diversity in proteins

13. Proteins Proteins are the doers of life Controls rates of reactions
Regulate cells processes
Form bones and cells
Transport substances into and out of cells

14. Proteins

15. Organic Macromolecules
Compound
Subunit(s)
Elements
Function
Examples
Carbohydrates
Glucose or sugar
C, H, O
Main energy source
Structure
glucose, starch, cellulose, glycogen
Lipids
(fats & oils)
Glycerol and 3 fatty acids
Energy storage
Protective coverings
Phospholipids, steroids
Proteins
Amino acids
C,H,O,N, & usu. S
Muscles/
bones/
structure
Control reaction rates
Regulation
Transport substances
Fight disease
Insulin, enzymes, hemoglobin, muscle fibers
Nucleic acids
Nucleotides
C, H, O, N, P
Store and transmit genetic information
DNA, RNA

16. Chemical Reactions
Chemical reactions involve the breaking of bonds in reactants and the formation of new bonds in products
Those entering the reaction are reactants
Products are produced by the reaction

17. Chemical Reactions
Equations must balance. Atoms are not created or destroyed, just rearranged.
Example: 2H2 + O H2O
Reactants are on the left and enter into the reaction.
Products are on the right and result from the reaction.
Metabolism – All of the chemical reactions that occur within an organism.

18. Energy in Reactions 2H2 + O2 2H2O Occurs naturally, releasing energy
The reverse reaction: 2H2O H2 + O2 requires so much energy it rarely occurs

19. Chemical Reactions
Activation energy – energy needed to get a reaction started.
Catalyst – substance that speeds up the rate of a chemical reaction.
Enzymes – proteins that speed up chemical reactions because they lower the activation energy. Enzymes provide a site where reactants can be brought together. (This reduces the energy needed for the reaction, called activation energy).
Substrate – the reactant(s) the enzymes fit.

20. Enzymes

21. Enzymes

22. Enzymes
Enzymes can be affected by any variable that affects chemical reactions including temperature and pH
Enzyme activity are regulated by cells often by turning them on or off

23. Characteristics of Enzymes
Specific (a special shape; use induced fit)
Reusable
Not consumed (used) in the reaction
Affected by factors such as pH and temperature.
Enzymes are specific because they are proteins made by folding into a 3-D shape (linked to their function).

24. Properties of Water Although water is neutral, it does have polarity
Water molecule is polar because of uneven distribution of electrons
The oxygen end has a slight negative charge
The hydrogen end has slight positive charge

25. Properties of Water
Due to its polarity, water can hydrogen bond with itself (attract itself)
Weaker than ionic bonding (NaCl)
Cohesion is attraction of molecules of same substance (beads of water)
Adhesion is attraction of molecules of different substances (water and graduated cylinder)

26. Properties of Water
Water is not always pure, it is often found as a mixture (material composed of two or more elements or compounds that are not chemically combined)
If the materials are evenly distributed it is called a solution
The substance that is dissolved is the solute
The substance that dissolves is the solvent

27. Properties of Water
When material does not dissolve a suspension is formed
Example: blood cells and water
The movement of the water keeps the small particles suspended

28. Acids and Bases
pH – A measure of how acidic or basic a solution is. Scale is 0 to 14. Below 7 is acidic. Above 7 is basic. 7 is neutral
Acidic solutions have higher concentration of H+ ions than pure water (pH 7)
Basic solutions have a lower concentration of H+ ions than pure water
Buffers – prevent sharp, sudden changes in pH

29. Acids and Bases

30. Acids and Bases