Zoology Module 1: Carbon in Organic Molecules

Study Notes

Carbon is an indispensable element of life, forming multiple bonds and long atom chains.
The arrangement of carbon groups determines the properties of a carbon-containing molecule.
Carbon skeletons form the basis of most organic molecules and can vary in length, branching, double bond position, and presence of rings.

There are 7 different functional groups directly involved in chemical reactions.
Hydroxyl group (polar, forms hydrogen bonds with water, compound name: alcohol)
Carbonyl group (ketone or aldehyde, compound name: ketone or aldehyde)
Carboxyl group (acts as an acid, compound name: carboxylic acid or organic acid)
Amino group (acts as a base, compound name: amine)
Sulfhydryl group (two SH groups can react, compound name: thiol)
Phosphate group (contributes negative charge, releases energy when combined with water, compound name: organic phosphate)
Methyl group (affects gene expression, compound name: methylated compound)

Carbohydrates are polyhydroxy aldehydes and ketones, including sugars and polymers of sugar.
Functions of carbohydrates include:
- Sources of energy (glucose)
- Stores energy (glycogen and starch)
- Structural materials (cellulose and chitin)
- Cell to cell recognition (plants and fungi create own cell wall)
Ways to classify carbohydrates:
- By functional groups (aldehyde or ketone)
- By number of carbon atoms (triose, tetrose, pentose, hexose)
- By sugar units (mono, di, poly)

Lipids do not include true polymers and are hydrophobic and varied in form and function.
Functions of lipids include:
- Sources of energy (fatty acids and fat-soluble vitamins A, D, E, and K)
- Stores energy (triglycerides)
- Structural materials (phospholipids, steroids, and waxes)
Types of lipids:
- Fats (hydrocarbon chain + carboxylic acid)
- Triglycerides (3 fatty acids + glycerol)
- Phospholipids (phosphate group + glycerol + fatty acid chain)
- Steroids (cholesterol, fat-soluble vitamins, steroid hormones, and bile salts)
- Waxes (animal waxes: beeswax, lanolin, spermaceti wax, and feather wax; plant waxes: cuticle and jojoba wax)

Proteins are diverse, polymers of amino acids, and essential for living things.
Levels of protein structure:
- Primary structure (chain of amino acids)
- Secondary structure (coiling or folded pattern stabilized by hydrogen bonds)
- Tertiary structure (final shape of the polypeptide)
- Quaternary structure (aggregation of multiple subunits)
Types of proteins:
- Structural proteins (provide structural framework and support, e.g., silk, keratin, and collagen)
- Enzymatic proteins (catalysts, speeding up chemical reactions)
- Defensive proteins (provide defense against infection and hemorrhage, e.g., antibodies, thrombin, and fibrinogen)
- Contractile proteins (facilitate movement, e.g., cytoskeleton, motor proteins, and locomotory structures)
- Transport proteins (carry out transportation of substances, e.g., hemoglobin and transporter proteins)
- Regulatory proteins (regulate and coordinate organ function, e.g., hormones, growth factors, and transcriptional and translational factors)
- Receptor proteins (binding site of ligands and participates in signal transduction, e.g., acetylcholine receptors)