Cell Structure And Functionbiomolecules 3

Amino Acids:

• Amino acids are the building blocks of proteins.
• They contain an amino group (-NH2), a carboxyl group (-COOH), a hydrogen atom, and a side chain (R group) that varies among different amino acids.
• There are 20 standard amino acids that are commonly found in proteins.

Structure of Amino Acids:

• The central carbon atom (α-carbon) in amino acids is bonded to the amino group, carboxyl group, hydrogen atom, and the side chain (R group), which determines the specific amino acid.

Proteins:

• Proteins are large, complex macromolecules that play critical roles in the structure, function, and regulation of cells and organisms.
• They are involved in various biological processes, including enzyme catalysis, structural support, immune response, transportation of molecules, and cell signaling.
• Proteins are composed of amino acid monomers linked together by peptide bonds.

Structure of Proteins:

• Proteins have a hierarchical structure consisting of four levels:

  1. Primary Structure: The linear sequence of amino acids in a protein chain.

  2. Secondary Structure: Local folding patterns in a protein chain, often forming alpha helices or beta sheets.

  3. Tertiary Structure: The overall three-dimensional arrangement of the protein’s polypeptide chain, including the folding of secondary structures.

  4. Quaternary Structure: The arrangement of multiple protein subunits (polypeptide chains) in a complex protein with multiple subunits.

Types of Protein Structure:

• Primary Structure: The sequence of amino acids in a protein.

• Secondary Structure: Localized folding patterns within a protein chain, including alpha helices and beta sheets.

• Tertiary Structure: The overall three-dimensional structure of a single protein chain, formed by interactions between amino acids and side chains.

• Quaternary Structure: The arrangement of multiple protein subunits (polypeptide chains) in a protein complex.

Introduction to Lipids:

• Lipids are a diverse group of hydrophobic organic molecules.

• They include fats, oils, phospholipids, steroids, and waxes.

• Lipids serve various functions in living organisms, including energy storage, insulation, cell membrane structure, and signaling.

• Fats and oils, composed of triglycerides, are common energy storage molecules in animals and plants.