1. Basic Chemistry Water Acids, Bases and pH
Cell Compounds
Basic Chemistry
Water
Acids, Bases and pH

2. Basic Chemistry Organic versus Inorganic Compounds
Organic compounds are the basis of all living things – those present in living organisms are grouped into four types
All compounds are made of bonded atoms
Covalent Bonds, Polar Covalent, Ionic Bonds
Atoms bond to become more stable – through sharing electrons.
Different degrees of sharing result in different bonds.
Polar molecules have dipoles where there are regions of positive and negative areas.

3. Water All living things depend on water Inorganic, Covalent, Polar O H
Negative dipole O H
Positive Dipole

4. Water
Hydrogen Bonding: attractive forces between adjacent water molecules O H δ- δ+ O H δ- δ+ O H δ- δ+

5. High Heat Capacity Excellent Solvent Transparent
Water
Hydrogen Bonding gives water some very important properties.
High Heat Capacity
Excellent Solvent
Transparent
Greatest Density at 4˚C
Cohesive
Lubricant

6. Acids and Bases

7. Acids
Acids are molecules that dissociate to release hydrogen ions (H+)
Strong acids such as hydrochloric acid dissociate easily:
HCl → H+ + Cl-
Weak acids dissociate to a much lesser extent
H2O → H1+ + OH1-

8. Bases Bases are molecules that release hydroxide ions (OH1-)
Bases combine with Acids to neutralize them
H1+ + Cl1- + Na1+ + OH1-→ H2O + NaCl

9. pH A measure of the amount of free H1+ -log[H1+] Range of 1-14
7 is neutral
< 7 is acidic and >7 is basic
In organisms pH is very important
Buffers help to maintain pH by binding with excess hydrogen or hydroxide ions

10. In Review Organic Compounds will be examined throughout this course.
Inorganic Compounds like acids, bases and water are important in living systems.
Hydrogen Bonding gives water many properties that make it significant in all living things.

11. Homework
For each property of water – explain what the property is and how it is important in living systems.
Describe dehydration synthesis and hydrolysis
For each of the following compounds provide an example and draw its structure.
a) Carbohydrate
b) Lipid
c) Protein
d) Nucleic Acid