Organic Molecules and Carbon Chemistry

Bulk Elements and Organic Molecules

Organic chemistry focuses on molecules containing carbon, which is the most abundant element in living systems (excluding water). Organic molecules are defined as compounds with covalently linked carbon atoms, often bonded to hydrogen, oxygen, nitrogen, phosphorus, and sulfur (CHNOPS).

• Organic molecules: Molecules with covalently linked carbon atoms.

• Hydrocarbons: Molecules made of only carbon and hydrogen atoms.

• Key elements: Carbon, hydrogen, oxygen, nitrogen, phosphorus, sulfur.

Example: Identifying organic molecules and hydrocarbons in chemical structures.

Carbon as a Building Block

Carbon's ability to form four covalent bonds makes it a flexible "atomic building block" for a variety of molecules. Carbon backbones can vary in length, position of double bonds, branching, and ring forms.

• Length: Carbon chains can be short or long.

• Double bonds: Carbon atoms can form double bonds at various positions.

• Branching: Carbon chains can be branched or unbranched.

• Ring forms: Carbon atoms can form ring structures.

Example: Variations of carbon backbones in organic molecules.

Functional Groups in Organic Chemistry

Definition and Importance

Functional groups are specific groups of atoms that are reactive and commonly found together. They typically extend off the carbon backbone and determine the chemical properties and reactivity of organic molecules.

• Common functional groups in biology: Hydroxyl, carbonyl, carboxyl, amino, sulfhydryl, phosphate, methyl.

• Role: Functional groups participate in chemical reactions and influence molecular interactions.

Example: Identifying functional groups in molecular structures.

Biomolecules: Classes and Structure

Definition and Primary Classes

Biomolecules are organic molecules essential to living organisms. There are four primary classes:

• Carbohydrates

• Proteins

• Nucleic Acids

• Lipids

Example: Visual representation of biomolecule classes and their functions.

Monomers and Polymers

Monomers are individual building blocks that can be repetitively linked to form polymers. Polymers are long chains of monomers linked together. The type of monomer depends on the biomolecule:

• Carbohydrates: Monosaccharides

• Proteins: Amino acids

• Nucleic acids: Nucleotides

Polymerization: Dehydration and Hydrolysis

Polymers are formed and broken down by two key reactions:

• Dehydration synthesis: Forms covalent bonds between monomers, releasing water ().

• Hydrolysis: Breaks covalent bonds by adding water, splitting polymers into monomers.

Equation for dehydration synthesis:

Equation for hydrolysis:

Carbohydrates: Structure and Function

Definition and General Formula

Carbohydrates are carbon-based molecules hydrated with many hydroxyl groups (–OH). They are also referred to as sugars. The general formula for simple carbohydrates is .

• Monosaccharides: Simple sugars (e.g., glucose, )

• Oligosaccharides: Short chains of covalently linked monosaccharides

• Polysaccharides: Long chains of covalently linked monosaccharides

Formation and Breakdown of Polysaccharides

Polysaccharides are formed by dehydration synthesis, linking monosaccharides via glycosidic bonds. Hydrolysis breaks these bonds, releasing energy and producing individual monosaccharides.

• Glycosidic bond: Covalent bond joining two monosaccharides.

• Dehydration synthesis:

• Hydrolysis:

Carbohydrate Functions

Structural Support and Energy Storage

Carbohydrates serve two main functions in living organisms:

• Structural support: Building materials for cell walls and exoskeletons (e.g., cellulose in plants, chitin in insects).

• Energy storage: Storage of glucose in the form of starch (plants) and glycogen (animals).

Example: Starch is the main energy storage polysaccharide in plants, while glycogen serves this role in animals. Cellulose provides structural support in plant cell walls, and chitin is found in the exoskeletons of insects and crustaceans.

Additional info: These notes cover foundational concepts in organic and biological chemistry relevant to General Chemistry, including molecular structure, functional groups, biomolecule classification, and carbohydrate chemistry.