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Biological Foundations: Atoms, Biomolecules, and Human Nutrition

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Atomic Foundations of Life

Democritus and Atomic Theory

  • All matter is made of atoms.
  • Different types of atoms exist.
  • Atoms cannot be broken down.

All matter is composed of atoms. The different types of atoms, known as chemical elements, are organized on the periodic table.

Bioelements: Essential Building Blocks

Bioelements are chemical elements that are essential for life. They are categorized into two main types:

Primary Bioelements: Forming 90% of Living Matter

  • C = Carbon
  • H = Hydrogen
  • O = Oxygen
  • N = Nitrogen
  • P = Phosphorus
  • S = Sulfur

Secondary Bioelements: Comprising 10% of Living Matter

  • Na = Sodium
  • K = Potassium
  • Fe = Iron
  • Mg = Magnesium

Essential Biomolecules

Molecular Union of Atoms

Biomolecules are molecules that are integral components of living organisms.

Nutrients are biomolecules present in food that can be utilized by the body.

Types of Biomolecules

Biomolecules are broadly classified into two types:

Inorganic Biomolecules: Simple Compounds

These are simple compounds that typically do not contain carbon. Examples include water and mineral salts.

Organic Biomolecules: Complex Carbon Compounds

These are more complex compounds that contain carbon. They include carbohydrates, lipids, proteins, and vitamins.

The Importance of Water (H2O)

Water is crucial for life because:

  • It is involved in chemical reactions (e.g., oxidation, iron transport in blood).
  • It is an integral part of the structure of many organs (e.g., calcium salts in bones).

Organic Biomolecules in Detail

Carbohydrates: Primary Energy Source

Carbohydrates play a key energetic role. There are three main types:

  1. Monosaccharides: Single sugar molecules.
  2. Disaccharides: Unions of two monosaccharides, which can be identical or different.
  3. Polysaccharides: Unions of many monosaccharides, which can be identical or different.

Lipids: Diverse Roles, Energy Storage

Lipids comprise several types of molecules, some of which are important for energy storage.

Proteins: Structural and Functional Roles

Proteins serve structural functions (e.g., membrane proteins) and are involved in chemical reactions.

Vitamins: Regulating Metabolic Reactions

Vitamins function to regulate metabolic reactions.

Dietary Fiber (Cellulose): Indigestible but Essential

Plant fiber, primarily cellulose, is formed by chains of glucose that our digestive system cannot break down. It helps move undigested food remains through the intestines and prevents constipation.

Nutrient Classification and Energy

Nutrient Categories

Nutrients can be classified into three types based on their primary function:

  1. Energy-Yielding Nutrients: Produce energy in the form of ATP. These are rich in carbohydrates and lipids.
  2. Structural Nutrients: Provide matter for growth and repair. They are abundant in minerals and proteins.
  3. Regulatory Nutrients: Control metabolic reactions. They are abundant in vitamins, mineral salts, and some proteins.

The Need for Matter and Energy

Living organisms require both matter and energy to survive.

Energy is measured in joules and calories.

1 kilocalorie (kcal) = 1000 calories (cal).

Factors Influencing Energy Expenditure

  • Physical Activity: Higher intensity physical activity necessitates more energy.
  • Organ and Tissue Activity: In younger individuals, organs often work with greater intensity, leading to higher energy expenditure.
  • Environmental Conditions: Extreme cold or heat necessitates more energy to maintain body temperature, even without physical activity.

Energy Calculation Formulas

Approximate daily energy needs can be estimated using these formulas (variables interpreted as: [Weight in kg] and [Height in cm]):

  • Men: 16.6 * 77 * [Weight in kg] + [Height in cm] + 572
  • Women: 7.4 * [Weight in kg] + 428 * [Height in cm] + 572

Food Preservation and Modern Concepts

Food Preservation Techniques

Methods used to kill germs and prevent food spoilage include:

  • Sterilization
  • UHT (Ultra-High Temperature) Processing
  • Pasteurization
  • Vacuum sealing
  • Dehydration
  • Refrigeration
  • Freezing
  • Additives

Food Selection and Quality

Food selection refers to the human capacity to choose suitable food variants and avoid those unfit for consumption.

Transgenic Organisms: Genetic Modification

Transgenic organisms are living beings that have had DNA from another living being implanted to improve their characteristics. Example: Genetically modified potato plants.

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