Biochemical Molecules Objectives

Biochemical Molecules

• Biochemical molecules are produced by living organisms. Most are organic molecules.
• Four major groups of biomolecules : polysaccharides, proteins, nucleic acids (DNA/RNA), and lipids
• These molecules are polymers, which are compounds made from repeating units called monomers or protomers. They are formed by polymerization.
• These molecules are mostly organic compounds. Organic compounds contain carbon atoms covalently bound to other atoms, especially carbon-carbon (C-C) and carbon-hydrogen (C-H) bonds.
• The four major elements in these molecules are carbon, hydrogen, oxygen, and nitrogen.

3.1. Biochemical Molecules: Objectives

• At the end of this section, students will be able to identify inorganic/organic biochemical molecules
• Discuss different inorganic ions and their contribution to the cell
• Explain the properties of water, including its importance to life.

3.1.1 Inorganic Molecules: Water

• Water (H₂O): Composed of two hydrogen atoms and one oxygen atom.
• Water is a polar molecule due to unequal electron sharing. Oxygen has a partial negative charge, and hydrogen has a partial positive charge.
• This polarity is significant in water's properties.

3.1.2 Inorganic Ions

• Charged particles formed when atoms gain or lose electrons.
• Positively charged ions are called cations (e.g., Na+, K+). Negatively charged ions are called anions (e.g., Cl−, PO43−).
• These ions often pair with oppositely charged ions.
• Inorganic ions are often found in living organisms, in either a free state (dissolved in cytoplasm) or bound to larger molecules.

3.1.3 Organic Molecules

• Include carbohydrates, lipids, proteins, and nucleic acids.
• Classified based on their constituent elements and the monomers from which they are constructed.
• The role of biological molecules in the cell structure is discussed, including the functions of carbohydrates, proteins, lipids, and nucleic acids to the body.
• Experiments are conducted to identify nutrients in different foodstuff.
• Explains why Ethiopians use malting seeds to make toodstuff.

Properties of Water

• Simple, yet complex, water has unique properties that are crucial to life.
• Molecular structure: Each hydrogen atom shares an electron pair with the oxygen atom.
• Water's polarity and associated electric dipoles cause significant chemical properties.
• Hydrogen Bonds: Interactions between partially charged atoms in water molecules.
• Water's hydrogen bonding network is essential for many unique properties.

Unique Water Properties

• High Specific Heat: Water absorbs a lot of heat without a significant temperature change.
• Cohesion and Adhesion: Water molecules stick to each other and other substances. This is crucial for processes like water transport in plants (cohesion), and capillary action (adhesion).
• Solvent Properties: Water is known as the universal solvent because it facilitates chemical reactions in biological systems. Attracts ions (e.g., Na+, Cl−) and polar molecules (e.g., sugars, glycerol).

Water's Importance For Ecosystems

• Stable boiling and freezing points prevent drastic environmental changes in bodies of water.
• Protects aquatic life from extreme temperature fluctuations.
• Water's properties regulate body temperature through sweating.

High Latent Heat of Vaporization

• The energy required to convert liquid water to a gas.
• Water has a high latent heat because of its strong hydrogen bonds. Significant energy is needed to break these bonds for water to evaporate.

Density and Freezing Properties

• Water's Density Behavior: Ice is less dense than liquid water, allowing it to float.
• Temperature effects: Water density decreases below 4°C; the reduced density of ice insulates water below, preventing complete freezing, and supporting aquatic life.
• Nutrient Circulation: Density changes create currents that help circulate nutrients in oceans.

High Surface Tension and Cohesion

• Cohesion: Water molecules stick together due to strong cohesive forces. This is important for processes like water transport in plants.
• Adhesion: Water molecules also adhere to other surfaces (e.g., glass); often stronger than cohesion.
• Capillary Action: Water climbs in narrow tubes (capillary action) due to adhesion to surfaces.
• Importance in Plants: Cohesive and adhesive forces are vital for water transport from roots to leaves.

Boiling and Freezing Points of Water

• Hydrogen Bonds: Influence the properties of water.
• High Boiling Point: Water boils at 100°C despite its low molecular weight; more energy is needed to break hydrogen bonds before boiling.
• Freezing Point: Water freezes at 0°C; similar energy considerations apply.

Inorganic Ions: Further Details

• Functions: Crucial in biological functions and various physiological processes.
• Importance: Found in trace amounts but are vital for health. Changes in concentrations can lead to serious health issues.
• Commonly Known As: Often referred to as minerals in the context of human health.
• Classification of Inorganic Ions: Macro-nutrients (daily diet) and micro-nutrients/trace elements (smaller amounts, often vital).
• Specific examples to be added later on: Sodium ions, potassium ions, calcium ions, phosphate ions, chloride ions, copper ions, and iron ions.

Inorganic Ions: Specific Ions

• Hydrogen Ions (H+): Crucial for maintaining balance and equilibrium. Part of pH regulation (scale 1-14).
• Sodium Ions (Na+): Essential nutrient, crucial for normal body function. Needed daily (3-6 grams). Commonly consumed in dietary salt; excess is eliminated through urine. Important in blood pressure regulation.
• Potassium Ions (K+): Essential nutrient, crucial for normal cellular functions and muscle, nerve functioning.
• Calcium Ions (Ca2+): Abundant in bones and teeth (99%). Crucial for many bodily functions.
• Phosphate Ions (PO43−): Important in bone health, in combination with calcium; found daily in diet.
• Chloride Ions (Cl−): Maintaining osmotic pressure and fluid balance, involved in acid-base balance and hydrochloric acid production.
• Iron Ions (Fe2+/Fe3+): Necessary for oxygen transport (hemoglobin). Plays a role in energy production.
• Copper Ions (Cu2+): Component of several important enzymes.
• Iodine Ions (I−): Plays a critical role in thyroid health and the production of thyroid hormones.

Clinical Conditions Related to Iron Metabolism

• Iron-Deficiency Anemia: Insufficient iron intake leads to reduced hemoglobin levels.
• Hemosiderosis: Excessive iron accumulation in the body.
• Hemochromatosis: Genetic condition with abnormal iron deposits in organs (liver, spleen).

Explore the fundamentals of biochemical molecules, including their types, structures, and significance in living organisms. This quiz covers organic and inorganic biochemical molecules, their properties, and the essential elements involved. Test your knowledge on the composition and importance of water and other biochemical substances.