Module 31,32,33

Key Concepts of Gene Expression and Regulation

Introduction

  • Classroom use only; contains copyrighted material.

Processes Involved

  • DNA Replication: Parent DNA strand is a template for new strand synthesis.

  • Transcription: DNA template leads to mRNA synthesis in the nucleus.

  • Translation: mRNA is translated into polypeptides in the cytoplasm. Ribosomes and tRNA are involved.

Gene Expression Flow

  • Sequence: DNA ➔ mRNA ➔ Protein.

Nucleic Acids

  • Structure: Polymers of nucleotides (5-carbon sugar, nitrogenous base, phosphate group).

  • Types: DNA (deoxyribose) and RNA (ribose).

  • Nitrogenous Bases: Pyrimidines (C, T, U) and Purines (G, A).

DNA Structure

  • Shape: Double helix with sugar-phosphate backbone.

  • Replicati?on Mechanism: Semiconservative, each strand serves as a template.

Central Dogma

  • Gene expression and regulation guiding processes.

DNA Replication Essentials

  • Key Enzymes: DNA polymerase, helicase, topoisomerase, DNA ligase.

  • Directionality: DNA synthesizes in the 5′ to 3′ direction.

Leading and Lagging Strands

  • Leading Strand: Synthesized continuously; Lagging Strand: Synthesized in Okazaki fragments.

Telomeres

  • Function: Prevent chromosome shortening and protect genetic data during replication.

  • Role of Telomerase: Adds telomeric sequences.

Transcription Overview

  • Begins at promoter, ends at terminator.

  • Eukaryotic mRNA requires processing (5' cap, poly(A) tail, splicing).

Alternative Splicing

  • Produces different proteins from the same transcript.