• Nucleic Acids

Structure:

• Nucleic acids are large macromolecules composed of nucleotides.
  • A nucleotide consists of:
    1. A phosphate group
    2. A pentose sugar (deoxyribose in DNA and ribose in RNA)
    3. A nitrogenous base (Adenine [A], Thymine [T] for DNA, Uracil [U] for RNA, Cytosine [C], and Guanine [G])
• There are two main types of nucleic acids:

1. DNA (Deoxyribonucleic acid): Double-stranded helix structure, with a sugar-phosphate backbone and nitrogenous base pairs (A-T, C-G) held together by hydrogen bonds.
2. RNA (Ribonucleic acid): Single-stranded, with a ribose sugar and uracil replacing thymine (A-U, C-G).

Functions:

• DNA:
  • Genetic Information Storage: DNA stores genetic information used for the growth, development, functioning, and reproduction of organisms.
  • Replication: DNA replication ensures that genetic material is passed on during cell division.
  • Protein Synthesis: DNA contains the instructions for building proteins through transcription and translation.

• RNA:
  • Messenger RNA (mRNA): Carries genetic information from DNA to the ribosome for protein synthesis.
  • Transfer RNA (tRNA): Brings amino acids to the ribosome during protein synthesis.
  • Ribosomal RNA (rRNA): Forms the structural and catalytic core of the ribosome, facilitating protein synthesis.

2. Enzymes

Structure:

• Enzymes are biological catalysts that speed up chemical reactions without being consumed in the process.
  • Primary Structure: Sequence of amino acids forming a polypeptide chain.
  • Secondary Structure: The folding of the polypeptide chain into alpha-helices and beta-pleated sheets.
  • Tertiary Structure: The three-dimensional shape of the enzyme, essential for its function, with the active site where the substrate binds.
  • Quaternary Structure: Some enzymes are made up of multiple polypeptide chains (subunits).

Functions:

• Catalysis of Biochemical Reactions: Enzymes lower the activation energy required for a reaction to occur, speeding up metabolic processes.
• Specificity: Enzymes are highly specific for their substrates, meaning they only catalyze particular reactions.
• Regulation: Enzyme activity can be regulated by various factors such as temperature, pH, and the presence of inhibitors or activators.
• Types of Enzymes:
  • Hydrolases: Catalyze hydrolysis reactions (e.g., digestive enzymes like amylase).
  • Oxidoreductases: Catalyze oxidation-reduction reactions (e.g., dehydrogenases).
  • Transferases: Transfer functional groups between molecules (e.g., kinases).
  • Ligases: Join two molecules (e.g., DNA ligase).

Examples:

• Amylase: Breaks down starch into sugars.
• Lipase: Breaks down lipids (fats) into fatty acids and glycerol.
• DNA Polymerase: Involved in DNA replication, catalyzing the addition of nucleotides to form DNA strands.

3. Vitamins

Structure:

• Vitamins are organic compounds required in small amounts for normal metabolism and are classified into two groups based on their solubility:
  1. Water-Soluble Vitamins: Vitamin C (ascorbic acid) and the B-complex vitamins (B1, B2, B3, B6, B12, folic acid, biotin, pantothenic acid).
  2. Fat-Soluble Vitamins: Vitamin A, D, E, and K.

Functions:

• Vitamin A:
  • Function: Essential for vision, immune system function, skin health, and growth.
  • Deficiency: Can lead to night blindness and dry skin.

• Vitamin B Complex:
  • Function: Each B vitamin has a specific role, including energy metabolism (B1, B2, B3), red blood cell production (B12, folate), and nervous system function (B6).
  • Deficiency: Can cause conditions like beriberi (B1 deficiency), pellagra (B3 deficiency), or anemia (B12 or folate deficiency).

• Vitamin C (Ascorbic Acid):
  • Function: An antioxidant that helps in collagen formation, wound healing, and iron absorption.
  • Deficiency: Can lead to scurvy, with symptoms such as gum bleeding and weakness.

• Vitamin D:
  • Function: Promotes calcium absorption in the intestines, essential for bone health.
  • Deficiency: Leads to rickets (in children) or osteomalacia (in adults).

• Vitamin E:
  • Function: Acts as an antioxidant, protecting cells from damage by free radicals.
  • Deficiency: Rare but can cause nerve and muscle damage.

• Vitamin K:
  • Function: Essential for blood clotting and bone health.
  • Deficiency: Can cause excessive bleeding or bruising.