Molecular Biology Overview Quiz

Molecular Biology

• Definition:

  • Molecular Biology is the branch of biology that deals with the molecular basis of biological activity.

• Key Concepts:

  • DNA Structure:

    • Double helix composed of nucleotides (adenine, thymine, cytosine, guanine).
    • Antiparallel strands with complementary base pairing (A-T, C-G).

  • DNA Replication:

    • Semi-conservative process.
    • Enzymes involved:
      • DNA helicase (unwinds DNA).
      • DNA polymerase (synthesizes new strands).
      • DNA ligase (joins Okazaki fragments on the lagging strand).

  • Transcription:

    • Process of synthesizing RNA from a DNA template.
    • Involves RNA polymerase binding to the promoter region.
    • Produces messenger RNA (mRNA).

  • Translation:

    • Synthesis of proteins from mRNA.
    • Occurs in ribosomes.
    • Involves:
      • tRNA (transfers amino acids).
      • Codons (triplet sequences on mRNA matching tRNA anticodons).

• Gene Expression:

  • Regulation of how much and when a gene is expressed.
  • Involves transcription factors and epigenetic modifications.

• Protein Structure:

  • Four levels:
    • Primary (amino acid sequence).
    • Secondary (alpha helices and beta sheets).
    • Tertiary (3D shape).
    • Quaternary (multiple polypeptide chains).

• Techniques:

  • PCR (Polymerase Chain Reaction): Amplifies DNA segments.
  • Gel Electrophoresis: Separates DNA/RNA/proteins based on size.
  • CRISPR-Cas9: Genome editing technology for modifying DNA.

• Applications:

  • Genetic engineering (GMOs).
  • Gene therapy (treating genetic disorders).
  • Molecular diagnostics (detecting diseases).

• Key Organisms in Molecular Biology:

  • Escherichia coli (E. coli) as a model organism.
  • Yeast (Saccharomyces cerevisiae) for eukaryotic studies.

• Current Trends:

  • Synthetic biology (designing and constructing new biological parts).
  • Bioinformatics (using computational tools for biological data analysis).

Overview of Molecular Biology

• Molecular Biology studies the molecular foundations of biological functions and processes.

DNA Structure

• Composed of nucleotides: adenine (A), thymine (T), cytosine (C), and guanine (G).
• DNA forms a double helix with antiparallel strands.
• Base pairing rules: A pairs with T, and C pairs with G.

DNA Replication

• Semi-conservative mechanism: each new DNA molecule retains one original strand.
• Key enzymes:
  • DNA helicase: Unzips the DNA double helix.
  • DNA polymerase: Synthesizes new complementary strands.
  • DNA ligase: Connects Okazaki fragments on the lagging strand.

Transcription

• Process of producing RNA from a DNA template.
• Initiated by RNA polymerase binding at the promoter region.
• Results in the formation of messenger RNA (mRNA).

Translation

• The conversion of mRNA sequences into proteins occurs in ribosomes.
• tRNA brings amino acids aligned with codons on mRNA, ensuring proper assembly of the protein.

Gene Expression

• Involves regulation of gene activity—how often and when genes are expressed.
• Influenced by transcription factors and epigenetic changes affecting DNA accessibility.

Protein Structure

• Has four hierarchical levels:
  • Primary: Sequence of amino acids.
  • Secondary: Formation of alpha helices and beta sheets.
  • Tertiary: Overall 3D folding of a single polypeptide.
  • Quaternary: Association of multiple polypeptide chains.

Techniques in Molecular Biology

• PCR (Polymerase Chain Reaction): Method to amplify specific DNA segments.
• Gel Electrophoresis: Technique for separating nucleic acids and proteins based on size.
• CRISPR-Cas9: Advanced genome editing tool for precise DNA modifications.

Applications

• Genetic engineering leads to the creation of genetically modified organisms (GMOs).
• Gene therapy aims to treat and potentially cure genetic disorders.
• Molecular diagnostics facilitate the detection of health conditions through biological markers.

Key Organisms

• Escherichia coli (E.coli): Widely used as a model organism in research.
• Saccharomyces cerevisiae: A yeast species important for studies in eukaryotic biology.

Current Trends

• Synthetic biology: Focus on creating novel biological parts and systems.
• Bioinformatics: Utilization of computational methods for analyzing biological data.