2. Chemistry of Life Bio.2 a,b – Cells Macromolecules Molecules Atoms

3. Element- a substance that cannot be divided into simpler substances –Ex: C,H,N,O,P,S Atom- the smallest particle of an element.

4. –Parts of atom –Neutron- neutral particle –Proton- positive particle –Electron- negative particle; move around atom –Nucleus- center of atom; made of protons and neutrons

5. Molecule- smallest unit of most compounds that displays all the properties of that compound. Results when 2 atoms are joined by covalent bonds Compound- A substance made of 2 or more atoms of different elements Polar molecule- molecules with unequal areas of charge.

6. Polar Molecules One atom pulls harder on the electrons than the others in the molecule. The atom pulling harder has a partial negative charge and the atoms that are weaker have a partial positive charge. Ex- Water: the oxygen pulls harder on the electrons than the hydrogen.

8. Bonds Ionic Bonds- formed when one or more electrons are transferred from one atom to another –Atoms that are charged bc of a gain or loss of electrons are called ions

9. Covalent bonds- bonds formed when two atoms share electrons

10. Hydrogen Bonds- a weak bond that forms between 2 polar molecules like water.

11. Van der Walls forces: weak intermolecular forces

12. Water!!! Essential for life on earth because:

13. https://www.youtube.com/watch?v=EOH4g B15qYIhttps://www.youtube.com/watch?v=EOH4g B15qYI

14. 1. Water prevents lakes and oceans from freezing solid. B/c ice floats oceans do not freeze solid and organisms can live below. Ice forms layer of insulation between cold air temperatures and water below.

15. 2. Water allows organisms to get rid of excess heat… B/c water absorbs heat when it evaporates off of skin.

16. 3. Water stabilizes temperatures on earth Water has a very high specific heat capacity. It takes a lot of energy to change the temperature of water.

17. 4. About 2/3 of the mass of a cell is made of water so most of the biochemical processes of life occur in water solutions. Why?

18. Water is the universal solvent (most things dissolve in water) so this provides a way for nutrients and wastes to be transported. Ex- food molecules transported in blood which is mostly water.

19. Reasons why water is good solvent and transporter… 1. Cohesion- water molecules stick to each other because of the attraction of hydrogen bonds (moves through places together, forms a long chain of molecules) Also causes “surface tension”. Prevents surface of water from easily breaking.

21. 2.Adhesion- Water is attracted to other substances’ positive and negative charges (acts like a tiny magnet for charged molecules)

22. Causes capillary action- water moves upward through a narrow tube such as a plant stem b/c it is attracted to walls of tube

23. Ex- Water in blood sticks together and moves through vessels is one stream (cohesion) and dissolves nutrients like sugar by attaching nutrients to itself to be transported through body (adhesion).

24. Acids and Bases Water ionizes: water molecules “fall apart” H 2 O  H+(hydrogen ion) + OH- (hydroxide ion)

25. Pure water- Has an equal number of H+ ions and OH- ions, considered neutral. Acid- A compound that forms more hydrogen ions when dissolved in water. Base- A compound that forms more hydroxide ions when dissolved in water.

26. pH Scale 0____________7_____________14 Acid- 0-6.9 Neutral –7 Base- 7.1-14

28. The pH of your various bodily fluids (blood, mucus, cellular fluids) has to have nearly constant pH to ensure proper function. There are acid-base buffer systems to maintain pH. –In all bodily fluids there are chemicals that can combine with strong acids or strong bases to weaken them.