DNA Replication Process

DNA Replication

• Process: The creation of two identical copies of DNA from one original DNA molecule
• Steps:
  1. Initiation: Unwinding of DNA at origin of replication, binding of helicase and topoisomerase
  2. Unwinding: Separation of DNA strands, creation of replication fork
  3. Synthesis: Leading strand synthesis continuous, lagging strand synthesis in short, discontinuous segments (Okazaki fragments)
  4. Elongation: Addition of nucleotides to leading strand, RNA primers removed and replaced with DNA
  5. Ligation: Sealing of gaps between Okazaki fragments
• Enzymes involved: Helicase, topoisomerase, primase, DNA polymerase, ligase

Gene Expression

• Definition: The process by which the information in a gene's DNA is converted into a functional product (protein or RNA)
• Steps:
  1. Transcription: Synthesis of RNA from DNA template
  2. Translation: Synthesis of protein from RNA sequence
• Regulation: Gene expression is regulated at multiple levels, including transcriptional, post-transcriptional, and post-translational
• Types of RNA: mRNA (messenger), tRNA (transfer), rRNA (ribosomal), miRNA (micro), siRNA (small interfering)

Genetic Engineering

• Definition: The manipulation of an organism's genome using biotechnology
• Techniques:
  • Recombinant DNA technology: Creation of recombinant DNA molecules by combining DNA from different sources
  • Gene cloning: Creation of multiple copies of a gene
  • Gene editing: Alteration of a gene's sequence using CRISPR-Cas9 or other methods
• Applications: Production of recombinant proteins, gene therapy, genetically modified organisms (GMOs)

Protein Synthesis

• Definition: The process by which cells create proteins
• Steps:
  1. Initiation: Binding of ribosome to mRNA, recognition of start codon
  2. Elongation: Addition of amino acids to growing polypeptide chain
  3. Termination: Recognition of stop codon, release of completed protein
• Components: mRNA, ribosomes, tRNA, amino acids
• Types of RNA involved: mRNA, tRNA, rRNA

Epigenetics

• Definition: The study of heritable changes in gene function that occur without a change in the underlying DNA sequence
• Mechanisms:
  • DNA methylation: Addition of methyl groups to DNA, typically silencing gene expression
  • Histone modification: Addition of various chemical groups to histone proteins, affecting chromatin structure and gene expression
• Inheritance: Epigenetic changes can be passed on to daughter cells, but may not be stable across generations
• Role in development and disease: Epigenetic changes play a crucial role in cellular differentiation and development, and have been implicated in various diseases, including cancer.

DNA Replication

• The process creates two identical copies of DNA from one original DNA molecule
• Initiation involves unwinding of DNA at origin of replication, binding of helicase and topoisomerase
• Unwinding results in separation of DNA strands, creation of replication fork
• Leading strand synthesis is continuous, while lagging strand synthesis occurs in short, discontinuous segments (Okazaki fragments)
• Elongation involves addition of nucleotides to leading strand, RNA primers removed and replaced with DNA
• Ligation seals gaps between Okazaki fragments
• Helicase, topoisomerase, primase, DNA polymerase, and ligase are the enzymes involved

Gene Expression

• Gene expression is the process by which the information in a gene's DNA is converted into a functional product (protein or RNA)
• Transcription involves synthesis of RNA from DNA template
• Translation involves synthesis of protein from RNA sequence
• Gene expression is regulated at multiple levels, including transcriptional, post-transcriptional, and post-translational
• There are five types of RNA: mRNA (messenger), tRNA (transfer), rRNA (ribosomal), miRNA (micro), and siRNA (small interfering)

Genetic Engineering

• Genetic engineering is the manipulation of an organism's genome using biotechnology
• Recombinant DNA technology creates recombinant DNA molecules by combining DNA from different sources
• Gene cloning creates multiple copies of a gene
• Gene editing involves alteration of a gene's sequence using CRISPR-Cas9 or other methods
• Applications include production of recombinant proteins, gene therapy, and genetically modified organisms (GMOs)

Protein Synthesis

• Protein synthesis is the process by which cells create proteins
• Initiation involves binding of ribosome to mRNA, recognition of start codon
• Elongation involves addition of amino acids to growing polypeptide chain
• Termination involves recognition of stop codon, release of completed protein
• mRNA, ribosomes, tRNA, and amino acids are the components involved
• mRNA, tRNA, and rRNA are the types of RNA involved

Epigenetics

• Epigenetics is the study of heritable changes in gene function that occur without a change in the underlying DNA sequence
• DNA methylation adds methyl groups to DNA, typically silencing gene expression
• Histone modification involves addition of various chemical groups to histone proteins, affecting chromatin structure and gene expression
• Epigenetic changes can be passed on to daughter cells, but may not be stable across generations
• Epigenetic changes play a crucial role in cellular differentiation and development, and have been implicated in various diseases, including cancer