Molecular Biology Lecture Notes

Introduction

• Molecular Biology: Study of living processes in terms of the chemical substances involved.
• Biological Components: Extremely small, similar to chemistry.
• Key Concept: Relate small components to larger biological concepts.

Importance of Carbon

• Carbon: Backbone of all living organisms.
• Structure: Four outer valence electrons, allows for up to four covalent bonds.
• Example: Methane (CH4) - one carbon and four hydrogen atoms.
• Organic Compounds: Built around carbon and generally contain hydrogen (e.g., methane).

Four Essential Macromolecules

1. Carbohydrates

   • Composition: Carbon, hydrogen, oxygen (1:2 ratio of oxygen to hydrogen).
   • Examples: Sugars, starches, cellulose.
   • Function: Short-term energy storage, structural components in plants.

2. Lipids

   • Composition: Carbon, hydrogen, oxygen (no specific ratio).
   • Examples: Fats, oils, waxes, phospholipids, cholesterol.
   • Function: Long-term energy storage, cell boundaries.

3. Proteins

   • Composition: Carbon, hydrogen, oxygen, nitrogen.
   • Building Block: Amino acids (N-C-C structure).
   • Examples: Enzymes.
   • Function: Regulate cellular processes, build cell structures.

4. Nucleic Acids

   • Composition: Carbon, hydrogen, oxygen, nitrogen, phosphorus.
   • Building Block: Nucleotides.
   • Examples: DNA, RNA, ATP.
   • Function: Carry information or energy.

Organic vs Inorganic Compounds

• Organic Compounds: Contain carbon and usually hydrogen; used in biological systems.
• Inorganic Compounds: Do not contain carbon; CO2 is an exception (contains carbon but no hydrogen).

Metabolism

• Definition: Sum of enzyme reactions in the body.
• Enzymes: Specialized proteins that speed up reactions.
• Functions:
  • Create materials for cellular functions.
  • Break down materials for energy.

Metabolic Processes

1. Anabolism

   • Building larger, more complex molecules from smaller ones.
   • Condensation Reaction: Monomers bond to form polymers, releasing water (H2O) as a byproduct.

2. Catabolism

   • Breaking down larger molecules into monomers.
   • Hydrolysis: Water is used to break bonds, forming original monomers.
   • Continuous Process: Anabolism and catabolism are ongoing, adjusting to cellular needs.

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