Chemicals of Life Notes

Organic compounds are carbon based
Common elements in organic compounds: C, H, O, N, S, P.
Carbon typically forms covalent bonds of 4 e^- pairs.
Each bond can be an intersection point for other groups of compounds.
Organic compounds form from straight chains, branched chains or closed rings of C.

Polymer Compounds

Polymers are molecules composed of a long chain of simpler similar molecules.

Carbohydrates
1. Mono- and disaccharides (sugars)
  1. Energy source for cells.
  2. Characterized by 3 to 7 C atoms in ring.
  3. Glucose, fructose, galactose, sucrose, maltose, lactose
2. Polysaccharides (many sugars)
  1. Can be 1 x 10⁶ monosaccharides long.
  2. Storage uses:
    - plants - starch (glucose polysaccharide).
    - animals - glycogen (highly cross-linked glucose polysaccharide).
  3. Structural uses:
    - plants : cellulose (glucose polysaccharide). Has bonds most organism can't break. Most abundant organic compound on Earth.
    - animals (arthropods) : chitin (polysaccharide of glucose + amino group).
Proteins
1. 50% of most cell dry weight.
2. Most structurally complex - unique 3D shape.
3. Polymers composed of amino acids.
4. Functions of Proteins
  1. Metabolism - enzymes
  2. Structural support - keratin.
  3. Storage - ovalbumin.
  4. Transportation - hemoglobin.
  5. Movement - actin & myosin.
  6. Defense - antibodies.
  7. Signaling (hormones) - insulin.
Nucleic acids (DNA, RNA)
Two types of nucleic acids: DNA and RNA

Composite Compounds

These are molecules composed of several distinct, different molecules.

Lipids
1. Lipids are hydrophobic.
2. Phosolipids form membranes !
3. Fatty acids with straight saturated fat tails pack well - solid fat.
4. Fatty acids with bent unsaturated tails don't pack well - liquid fat.
5. Bond a metal hydroxide with a fatty acid - soap!
6. Steroids have no fatty acids. Examples: cholesterol, some hormones (sex).
Nucleotides