Introduction to Molecular Biology

Introduction to Molecular Biology

• Molecular Biology is the study of biological processes at the molecular level
• Focuses on essential macromolecules like DNA, RNA, and proteins
• Investigates the interactions and pathways between these components
• Molecular biology is a relatively new field, with major developments occurring in the 20th century
• Utilizes techniques from physics and chemistry
• Molecular biology has applications in medicine, agriculture, and forensic science
• Bridges genetics, biochemistry, and cell biology

Key Molecules in Molecular Biology

• Nucleic Acids
  • DNA carries genetic information for all living organisms
  • RNA acts as a messenger and functional component in gene expression
    • mRNA is the messenger RNA that carries genetic code from DNA to ribosomes for protein synthesis
    • tRNA is transfer RNA that brings specific amino acids to the ribosome for protein synthesis
    • rRNA is ribosomal RNA that is part of the ribosome, essential for protein synthesis
• Proteins
  • Synthesized through translation in ribosomes
  • The sequence of amino acids in a protein determines its structure and function
  • Proteins perform a wide variety of cellular functions, including:
    • Catalysis (enzymes)
    • Structural support
    • Transport
    • Signaling

Major Processes in Molecular Biology

• DNA Replication
  • The process by which a cell duplicates its DNA before division
  • Each new cell receives an exact copy of the DNA
  • The enzyme DNA polymerase adds new nucleotides to form the complementary strand
  • Helicase unwinds the DNA double helix
  • Ligase joins DNA fragments together
• Transcription
  • The process by which DNA is copied into RNA
  • Occurs in three steps:
    • Initiation - RNA polymerase binds to the promoter region of the gene
    • Elongation - RNA polymerase adds complementary RNA nucleotides to form an mRNA strand
    • Termination - Transcription ends when the RNA polymerase reaches a stop signal on the DNA template
• Translation
  • The process where ribosomes synthesize proteins using information encoded in mRNA
  • Ribosomes read the mRNA in sets of three nucleotides called codons
  • Each codon corresponds to a specific amino acid
  • tRNA brings the appropriate amino acid to the ribosome
  • The amino acids are joined together to form a protein
• Gene Regulation
  • Not all genes are expressed at all times
  • Cells regulate gene expression based on their needs, environmental signals, and developmental stage
  • Gene regulation occurs at multiple levels, including transcription, RNA processing, and translation
  • Transcription factors, proteins that can increase or decrease transcription of specific genes

Technological Advancements in Molecular Biology

• Polymerase Chain Reaction (PCR): A technique used to amplify specific DNA sequences
• CRISPR-Cas9: A powerful gene-editing tool that allows for precise changes in the DNA sequence
• Next-Generation Sequencing (NGS): High-throughput sequencing technologies that provide detailed genetic information

Applications of Molecular Biology

• Medical Research
  • Molecular biology is crucial for understanding diseases at the genetic and molecular levels
  • Leads to the development of targeted therapies for conditions like cancer, genetic disorders, and infectious diseases
• Biotechnology
  • Genetic engineering, including creating GMOs and producing synthetic insulin, is made possible by molecular biology
• Forensics
  • DNA fingerprinting and sequencing are essential tools for identifying individuals and solving crimes.