I. Water & Solutions (161-165)
Water is the most essential and abundant substance on Earth. Cells are made up of mostly water and most cells are surrounded by water. The importance of water is largely due to its unique characteristics, which all directly relate to one very important property of water . . . Water is polar.
A. Polarity- label the picture to the left
1. unequal sharing of electrons in molecules formed with covalent bonds
2. How this works:
a. oxygen has 8 protons in nucleus & each hydrogen has 1 proton in their nucleus
b. 10 shared electrons will be more attracted to the more positively charged oxygen nucleus; thus orbiting around the oxygen end of the molecule just about all the time
c. The oxygen end will have a slightly negative charge
d. The hydrogen ends will have a slightly positive charge
e. Not true charges because the electrons are not transferred; just shared unequally
B. Hydrogen “Bonds”
1. not a true bond- does not form a new compound
2. attraction between two polar molecules; like water
3. attraction between slightly positively charged hydrogen end of one polar molecule and the slightly negatively charged end of another polar molecule
4. in water : forms between positively charged H end of one water molecule and the negative end of another water molecule
5. Label & Fill in the H bond on the picture to the left
C. Properties of Water Polarity give water unique properties important in maintaining homeostasis in organisms
1. Cohesion or Surface tension
a. Attraction between molecules of the same substance; water molecules stick together
2. Adhesion or Capillary action
a. attraction between molecules of different substances; water sticks to other surfaces
3. Universal Solvent
a. slightly charged ends of water attract and separate atoms of other compounds; dissolving them
b. anything dissolved in water is called a solution
c. many important substances in cells are in solution
4. High heat of vaporization
a. takes a lot of heat energy to evaporate a small amount of water
5. High specific heat
a. water absorbs heat energy without its temperature rising much
6. Expansion on Freezing
a. ice less dense than water; ice floats
II. pH scale
· Many solutes readily dissolve in water because of water’s polarity.
A. Acids-
1. a substance that releases a hydrogen ion (H+) when dissolved in water
2. The more (H+) hydrogen ions a substance releases, the more acidic the solution is
B. Bases-
1. A substance that releases hydroxide ions (OH-) when dissolved
2. The more (OH-) hydroxide ions a substance release, the more basic the solution is
C. pH and Buffers
The majority of biological processes carried out by cells occur between pH 6.5 - 7.5.
1. pH
a. the measure of concentrations of H+ ions in a solution
b. pure water is neutral and has a value of 7
c. acidic has an abundance of H+ and pH values lower than 7
d. basic has an abundance of OH- and pH values of higher than 7
2. Buffers
a. Mixtures that can react with acids or bases to keep the pH within a particular range
b. To maintain homeostasis it is important to control H+ levels.
Color the following diagrams according to the key.
The Building Blocks of LIFE (pp. 166-169) Organic Chemistry
I. Importance of Carbon- Although a cell is composed of 70-95% water most of the rest is carbon-based compounds.
A. Structure of Carbon
1. Atom # 6: 6 protons & 6 electrons; 2 in first shell & 4 in second
2. has 4 valance electrons- so can make four covalent bonds
3. can also form bonds w/other carbon atoms
4. compounds with carbon-carbon bonds called organic
B. Macromolecules-
· are large molecules that are formed by joining smaller molecules together
1. Polymers
a. these are large molecules made up of similar or identical building blocks
2. Monomers
a. are the building blocks or sub units of polymers
3. Biomolecules are Classes of macromolecules
a. carbohydrates c. proteins
b. lipids d. nucleic acids
II. Carbohydrates
A. Elements: C, H, O, always a 2:1 ratio of H atoms to O atoms (2H:1O)
B. Monomer: monosaccharide
C. Function: immediate and stored energy; building material
D. Where found in body: bloodstream, liver; cell walls of plants & fungus
E. Food source: sugar & starches
F. Examples:
1. Monosaccharides: (one sugar)
a. glucose (C6H12O6)- preferred energy molecule for most organism; including humans
b. galactose- one component of milk
c. fructose- found in some fruits
2. Disaccharides: two monosaccharides bonded together
a. sucrose- table sugar: glucose + fructose
b. lactose- milk sugar: glucose + galactose
3. Polysaccharides: many monosaccharides bonded together; two groups
a. Storage Polysaccharides: long polymers of glucose; broken down for needed energy
· Glycogen- Storage of glucose in animals Stored in liver & muscles
· Starch-Storage of glucose in plants. Humans can break down to glucose for energy
b. Structural Polysaccharides: used for building materials
· Cellulose - component of plant cell walls human unable to break down important source of fiber in our diet
· Chitin - Component of fungal cell walls. Component of insect and other arthropod exoskeletal
III. Lipids: (waxy, fatty or oily compounds)
A. Elements: C, H, O, many more H than in a carb.
B. Monomer: glycerol & fatty acids
C. Function: energy storage; insulation; cushioning
D. Where found in body: cell membrane; innermost layer of skin; surrounding some organs
E. Food Source: butter, shortening, olive oil, ect.
F. Examples:
1. Fats & Oils
a. all have 3 fatty acid tails
b. fats solid at room temperature
c. oils liquid at room temperature
d. saturated fats- no carbon-carbon double bonds
e. unsaturated fats- at least one carbon-carbon double bonds
f. saturated fats linked to heart disease
2. Phospholipids
a. found in every living cell membrane
3. Steroids
a. used for hormone production
b. used for animal cell structure
c. Ex. Cholesterol
IV. Proteins
A. Elements: C, H, O, N
B. Monomer: amino acids, only 20 different amino acids combine in different numbers, patterns, & arrangement
C. Function: support, structure, protection, movement, metabolism
D. Where found in body: muscles, hair, skin, enzymes
E. Food Source: meats, peanuts, eggs
F. Examples:
1. Enzymes
a. biological catalysts that trigger chemical reactions
b. lower the activation energy of a reaction
c. could not maintain homeostasis without them
d. Only affective in a narrow temperature and pH range
V. Nucleic Acids
A. Elements: C, H, O, N, P
B. Monomer: nucleotide
C. Function: genetic instructions & usable energy
D. Where found in body: nucleus of cells
E. Food Source: none
F. Examples:
1. DNA- Deoxyribonucleic acid
a. contains the genetic instructions for the cell
2. RNA- Ribonucleic acid
a. carries out the instructions in DNA
3. ATP- Adenosine triphosphate
a. provides useable energy for the cell
Color Code C-Green H= Blue O=Pink
Use the diagram of glucose to tell how many carbons, hydrogens, and oxygens are in a single molecule
#C ______# H ______# O ______
Color Code: C-Green H= Blue O=Pink N= Yellow
C-Green H= Blue O=Pink
How many: ______C ______H ______O
Glycerol:
Saturated fatty Acid
Unsaturated Fatty Acid - Double Bond
Nucleotide: Color and label the part of the nucleotide-
Sugar (5-sided)- green
Phosphate group (round)- yellow
Nitrogen base (6-sided)- blue
ATP: Color and label the ATP
Sugar (5-sided)- green
Phosphate group (round)- yellow
Nitrogen base (6-sided)- blue