Organic Molecules: Structure and Function

Carbon's Versatility

Carbon is a versatile atom due to its ability to form four covalent bonds with other atoms, including other carbon atoms. This allows carbon to create a wide variety of organic molecules with diverse structures and functions.

Definitions:

• Organic Compound: A compound containing carbon that is typically found in living organisms.
• Hydrocarbon: An organic compound consisting of only carbon and hydrogen atoms.
• Macromolecule: A large molecule formed by the joining of smaller repeating units (monomers). Examples include proteins, carbohydrates, and nucleic acids.

Dehydration and Hydrolysis Reactions

Dehydration Reaction:

A dehydration reaction is a chemical reaction where water is removed from the reactants to form a larger molecule. This process is involved in the synthesis of macromolecules.

Example:

• Glucose + Fructose → Sucrose + Water
• Glycerol + 3 Fatty Acids → Triglyceride + 3 Water Molecules

Hydrolysis Reaction:

A hydrolysis reaction is the reverse of a dehydration reaction. Water is added to a larger molecule, breaking it down into smaller units.

Four Major Biological Molecules

Subgroups of Carbohydrates

1. Monosaccharides: Simple sugars that cannot be broken down into smaller sugars. Example: Glucose, fructose.
2. Disaccharides: Double sugars formed by the joining of two monosaccharides. Example: Sucrose (table sugar), lactose.
3. Polysaccharides: Long chains of monosaccharides. Example: Starch, cellulose, glycogen.

Isomer:

Molecules that have the same molecular formula but different structural arrangements of atoms. For example, glucose and fructose are isomers.

Subgroups of Lipids

• Fats: Composed of glycerol and three fatty acids.
  • Saturated Fat: Fatty acid chains have the maximum number of hydrogen atoms. Example: Animal fats, butter.
  • Unsaturated Fat: Fatty acid chains contain one or more double bonds, resulting in fewer hydrogen atoms. Example: Plant oils.
• Steroids: Lipids with a carbon skeleton consisting of four fused rings. Example: Cholesterol, testosterone, estrogen.

Hydrogenation:

The process of converting unsaturated fats to saturated fats by adding hydrogen atoms to the double bonds in the fatty acid chains.

Five Main Types of Proteins

1. Enzymes: Catalyze (speed up) chemical reactions.
2. Structural Proteins: Provide support and shape to cells and tissues.
3. Storage Proteins: Store amino acids for later use.
4. Contractile Proteins: Involved in movement and muscle contraction.
5. Transport Proteins: Transport substances across cell membranes or throughout the body.

Similarities and Differences Between DNA and RNA

Similarities:

• Both are polymers of nucleotides.
• Each nucleotide consists of a sugar, a phosphate group, and a nitrogenous base.

Differences:

In DNA, the bases pair specifically: Adenine (A) with Thymine (T), and Guanine (G) with Cytosine (C).

Four Levels of Protein Structure

1. Primary Structure: The linear sequence of amino acids in a polypeptide chain.
2. Secondary Structure: Local folding patterns of the polypeptide chain, such as alpha-helices and beta-sheets.
3. Tertiary Structure: The overall three-dimensional shape of a polypeptide chain.
4. Quaternary Structure: The arrangement of multiple polypeptide chains (subunits) in a protein complex.