Biomolecules and Their Functions

Biomolecules

The four main types of biomolecules are:

  • Carbohydrates
  • Proteins
  • Lipids (fats and oils)
  • Nucleic Acids (DNA, RNA)

Importance of Food

Humans acquire the essential chemicals for growth and survival from food, which consists of plant and animal materials. Functions of food in the human body include:

  • Energy: Required for all physiological activities.
  • Growth: Necessary for cell production and replacement.
  • Mending of Damaged Tissue: Essential for recovery and maintenance of bodily functions.
  • Keeping the Body Healthy: Supports overall health and functionality.

Additionally, the diet must include:

  • Vitamins and Minerals: These are micronutrients crucial for various metabolic processes.
  • Water: Essential for maintaining hydration and homeostasis.
  • Fibre: Important for digestive health.

Carbohydrates

Carbohydrates are classified into:

  • Sugars: Simple carbohydrates that taste sweet and are quickly digested, converted to glucose (monosaccharide), and utilized by body cells.
    • Glucose: C₆H₁₂O₆, produced by plants during photosynthesis and used for energy in cellular respiration.
    • Sucrose: A disaccharide formed by linking two monosaccharides.
  • Starches: Complex carbohydrates that provide sustained energy over longer periods.
    • Glycogen: A polysaccharide stored in the liver and muscles of humans.
    • Cellulose: Found in the plant cell walls, composed of linked glucose molecules forming fibrous structures. Humans cannot digest cellulose, but it serves as dietary fiber and a prebiotic for gut bacteria.

Proteins

Proteins have multiple essential roles:

  • Structural: Form the body's tissues, including muscles, skin, and hair.
  • Transport: e.g., Hemoglobin in red blood cells carries oxygen.
  • Defense: Antibodies help fight infections.
  • Messengers: Hormones function as chemical messengers.
  • Movement: Proteins like actin and myosin are critical for muscle contraction.
  • Catalysis: Enzymes act as biological catalysts, expediting and regulating chemical reactions within cells.

Proteins are composed of approximately 20 different amino acids:

  • Essential Amino Acids: 9 amino acids must be obtained from dietary protein.
  • Non-Essential Amino Acids: 11 amino acids can be synthesized by the body.
  • Digestion: Proteins are degraded into amino acids by digestive enzymes before being reassembled in cells for various functions.

Fats (Lipids)

Fats serve as the primary energy storage form and have several key functions:

  • Energy Yield: Provide more than twice the energy of carbohydrates when metabolized.
  • Composition: Composed of three fatty acids linked to a glycerol molecule.
  • Functions:
    • Insulation: Helps to maintain body temperature.
    • Organ Protection: Cushions vital organs.
    • Hormone Production: Vital for synthesizing certain hormones.
    • Vitamin Storage: Important for the storage and transport of fat-soluble vitamins (A, D, E, K).
    • Phospholipids: Compose the cell membranes.

Vitamins

Vitamins are organic substances crucial for proper body function:

  • Essential: Required in small quantities for various biochemical reactions.
  • Deficiency Diseases: Inadequate vitamin intake can lead to specific health issues.
  • Classification:
    • Fat-Soluble Vitamins: A, D, E, and K, which are stored in fatty tissues and the liver.
    • Water-Soluble Vitamins: C and B-complex vitamins cannot be stored and are excreted via urine.

Types of Vitamins and Deficiency Diseases

  • Vitamin A:
    • Function: Maintenance of skin, hair, mucous membranes; bone and tooth growth.
    • Deficiency: Night blindness, dry scaling skin.
  • Vitamin B1 (Thiamine):
    • Function: Involved in energy metabolism.
    • Deficiency: Beri-beri.
  • Vitamin B2 (Riboflavin):
    • Function: Energetic metabolism.
    • Deficiency: Skin lesions, cracks at sides of mouth.
  • Vitamin B3 (Niacin):
    • Function: Energy metabolism.
    • Deficiency: Pellagra.
  • Vitamin B6:
    • Function: Tissue building and protein metabolism.
  • Vitamin B12:
    • Function: Aids cell development and nervous system functioning.
  • Folate:
    • Function: Genetic material development; red blood cell production.
    • Deficiency: Anemia, birth defects.
  • Vitamin C:
    • Function: Bone and cartilage structural support, muscle and blood vessel formation; aids iron absorption.
    • Deficiency: Scurvy.
  • Vitamin D:
    • Function: Bone and tooth formation; assists in nerve function and heart action.
    • Deficiency: Rickets.
  • Vitamin E:
    • Function: Protects blood cells, prevents nerve damage.
  • Vitamin K:
    • Function: Essential for blood clotting.
    • Deficiency: Leads to bleeding.

Minerals

Minerals are inorganic substances needed in small amounts for various body functions:

  • Functions:
    • Formation of bones and teeth.
    • Constituents of body fluids and tissues.
    • Components of enzyme systems.
    • Necessary for normal nerve function.
  • Classification:
    • Major Minerals: Needed in larger amounts, for example, calcium, phosphorus, magnesium, sodium, potassium, and chloride.
    • Trace Minerals: Required in smaller amounts, for instance, iron, zinc, iodine, fluoride, selenium, and copper.

Deficiency of certain minerals can lead to various health issues.

Biomolecules Overview

The four main types of biomolecules:

  • Carbohydrates
  • Proteins
  • Lipids (fats and oils)
  • Nucleic Acids (DNA, RNA)

Importance of Food

Humans need food for growth and survival. Functions of food:

  • Energy: Fuels physiological activities.
  • Growth: Supports cell production and replacement.
  • Mending Tissue: Aids in recovery and maintenance.
  • Health Maintenance: Promotes overall well-being.

Additionally, essential components of diet:

  • Vitamins and Minerals: Critical for metabolic processes.
  • Water: Maintains hydration and balance.
  • Fibre: Supports digestive health.

Carbohydrates

Types of carbohydrates:

  • Sugars: Simple, sweet, quick energy sources.
  • Glucose (C₆H₁₂O₆): Energy source from plants.
  • Sucrose: A disaccharide of two monosaccharides.
  • Starches: Long-lasting energy source.
  • Glycogen: Energy storage in humans.
  • Cellulose: Plant fiber, important for digestion (not digestible by humans).

Proteins

Key roles of proteins:

  • Structural: Build tissues (muscles, skin, hair).
  • Transport: e.g., Hemoglobin carries oxygen.
  • Defense: Antibodies fight infections.
  • Messengers: Hormones transmit signals.
  • Movement: Involved in muscle function.
  • Catalysis: Enzymes speed up reactions.

Proteins consist of amino acids:

  • Essential Amino Acids: 9 needed from diet.
  • Non-Essential Amino Acids: 11 created by the body.
  • Digestion: Proteins broken down into amino acids for various functions.

Lipids (Fats)

Functions of fats:

  • Energy Storage: More than twice the energy of carbohydrates.
  • Composition: Made of fatty acids and glycerol.
  • Insulation: Keeps body temperature stable.
  • Protection: Cushions organs.
  • Hormone Production: Necessary for specific hormones.
  • Vitamin Storage: Stores and transports vitamins A, D, E, K.
  • Cell Membrane: Phospholipids form cell membranes.

Vitamins

Key points about vitamins:

  • Essential: Needed in small amounts.
  • Deficiency Diseases: Lack leads to health issues.
  • Fat-Soluble Vitamins: A, D, E, K (stored in fatty tissues).
  • Water-Soluble Vitamins: C and B-complex (not stored).

Deficiencies:

  • Vitamin A: Night blindness, skin issues.
  • B1 (Thiamine): Beri-beri.
  • B2 (Riboflavin): Skin lesions.
  • B3 (Niacin): Pellagra.
  • B6 & B12: Tissue and cell development.
  • Folate: Anemia, birth defects.
  • Vitamin C: Scurvy (bone/cartilage issues).
  • Vitamin D: Rickets (bone growth issues).
  • Vitamin E: Protects blood cells.
  • Vitamin K: Blood clotting issues.

Minerals

Functions of minerals:

  • Bone Formation: Essential for healthy bones and teeth.
  • Body Fluids and Tissues: Key components.
  • Enzyme Functions: Vital for various processes.
  • Nerve Function: Necessary for normal function.

Classification:

  • Major Minerals: Calcium, phosphorus, sodium, etc. (needed in larger amounts).
  • Trace Minerals: Iron, zinc, iodine, etc. (needed in smaller amounts).

Deficiencies can lead to various health issues.