Question

Identify major classes of biomolecules and characteristic functional groups

Draw the structure of water molecules including atoms, orbital hybridization, bonds, lone pairs, partial charges, and dipole moments

Answer 1

Classification of biomolecules - There are four major classes of biomolecules:

1. Proteins - Proteins make up the majority of biomolecules present in a cell. These molecules have enormous variation. Proteins are responsible for many enzymatic functions in the cell and play an important structural role . Proteins are composed of subunits called amino acids.  

2. Nucleic acids - Nucleic acids are responsible for all of our genetic information. Nucleic acids are formed from subunits called nucleotides. There are 5 different types of nucleotides in the cell; Adenine, Thymine, Guanine, Cytosine and Uracil.

3. Carbohydrates - Carbohydrates provide an energy source for the cell and also may play a structural role. The simplest subunit of a carbohydrate is a monosaccharide. The structure of the glucose molecule is a good representation of carbohydrate subunits, also called a monomer.

4. Lipids - Lipids are composed of long hydrocarbon chains (-CH₂ -). These molecules hold an incredible amount of energy and are therefore energy storage molecules. Because of some pretty neat biochemical properties (hydrocarbons are hydrophobic), lipids are the major component of cell membranes.

Characteristic functional groups - Following are the characteristic functional groups present in biomolecules:

1. Alcohols - Alcohols are biomolecules that contain at least one hydroxyl group (R?OH).

2. Carbonyls - Carbonyl groups in aldehydes and ketones usually increase polarity and reactivity of organic molecules. The shorthand structural model for a carbonyl is >C=O.

3. Carboxyls - A carboxyl group contains both a carbonyl group and a hydroxyl group, bonded to the same carbon atom (R?COOH).

4. Amines - Amines are organic molecules containing an amino group (R?NH₂).

5. Phosphates - Phosphate groups (R?PO₄^2–) are highly acidic, almost exclusively existing in an ionized state in solutions by releasing two hydrogen ions. With four electronegative oxygen atoms, phosphate groups are highly reactive, and transfer of a phosphate group from one molecule to another delivers energy to chemical reactions.

Structure of water molecule -\