I. Atoms and Molecules in Cells.
A. 95% of cells are made up of 4 atoms (C, O, H, and N).
B. Cells are 80%-95% water.
C. What’s left are carbon-containing compounds = organic compounds.
D. Carbon atoms.
1. Readily bond with H, O, and N.
2. Readily bond with one another (Figure 3.2)
E. Four major groups of important organic molecules:
1. Carbohydrates
2. Lipids
3. Proteins.
4. Nucleic acids.
II. Carbohydrates.
A. Contain C, H and O.
B. Monosaccharides — simple sugars.
1. 3-6 C atoms, 6-12 H atoms and 3-6 O atoms (1 C : 2 H : 1 O).
2. Examples.
a. Glucose (C6H12O6) — the "food molecule."\
b. Fructose (C6H12O6) — "fruit sugar."
c. Glucose and fructose are isomers.
3. Figure 3.9
C. Disaccharides.
1. Two monosaccharides linked together.
2. Example: sucrose, common table sugar (fructose + glucose).
D. Polysaccharides.
1. Many monosaccharides linked together to form a macromolecule.
2. Polymers and monomers.
3. Examples.
a. Starch.
b. Glycogen.
c. Cellulose.
III. Lipids.
A. Fats.
1. Energy storage molecule.
2. Glycerol + 3 fatty acids (Figure 3.15)
B. Phospholipids -- fatty acid chain replaced with a phosphate group (PO3).
C. Steroids -- hormones important to growth, reproduction.
IV. Proteins: the most diverse group of biological molecules.
A. Various important functions.
1. Enzymes that control the rate of chemical reactions in cells.
2. Structural materials (e.g. hair, claws, nails, feathers).
3. Transport (hemoglobin).
4. Energy source.
B. Proteins are polymers of monomer subunits called amino acids
C. Amino acids contain C, H, O and nitrogen.
D. Components of amino acids (Figure 3.19).
1. amino group: -NH3
2. carboxyl group: -COOH
3. Side group.
E. 20 different amino acids in living material.
F. Examples: leucine and serine (Figure 3.19).
G. The peptide bond (Figure 3.20).
H. Polypetides and proteins.
I. The primary structure of proteins — e.g. lysozyme (Figure 3.21).
J. Protein function related to structure -- denaturatiom.
V. Nucleic acids. —
A. Long polymers of smaller subunits called nucleotides —
B. Macromolecules that control structure and function of a cell.
C. Important nucleic acids.
1. Deoxyribonucleic acid (DNA) -- the genetic material.
2. Ribonucleic acid (RNA) — involved protein synthesis.
D. Components of a nucleotide (Figure 3.24).
1. A 5-carbon sugar (e.g. ribose, deoxyribose).
2. A phosphate group.
3. A nitrogenous base
E. Nucleotides form chains called nucleic acids.
1. Chains have a sugar-phosphate backbone.
2. RNA: single chain of nucleotides.
3. DNA: double chain of nucleotides.
F. Figure 3.26a: a single DNA strand.
F. Figure 3.26a: the DNA double helix.
