Lecture Notes on Genetics

Introduction

• Speaker: Dr. Jim
• Topics Covered: Genetics, DNA, Transcription, Translation, Replication
• Cell Differences:
  • Bacteria: No nucleus, one chromosome
  • Eukaryotic Cells: Multiple chromosomes

Chapter Outline

• Part 1: Basic Genetics
• Part 2: Regulation, Mutations (next unit)

Key Concepts

Genetics Overview

• Definition: Study of heredity
• Bacterial Chromosome Structure:
  • Single circular DNA, 4-5 million base pairs
• Genes: Fundamental units of heredity
  • Genotype: Genetic makeup
  • Phenotype: Physical appearance

DNA Structure

• Nucleotide Components: Sugar, Phosphate, Nitrogenous Base (A, T, G, C)
• DNA Arrangement: 5'-3' manner
• Replication:
  • Semi-Conservative: One old, one new strand

Protein Synthesis

• Transcription: DNA to RNA
• Translation: RNA to Protein

DNA and Replication

• Genome: Total genetic material
  • Includes chromosomes, mitochondria, chloroplasts, plasmids
• Bacterial vs Eukaryotic Chromosomes:
  • Bacterial: Single loop, 4-5 million base pairs
  • Eukaryotic: Linear, 100-200 million base pairs
• Replication Process:
  • Involves 30 enzymes
  • Key Enzyme: Helicase (unzips DNA)

Transcription Details

• RNA Types:
  • mRNA: Carries DNA message
  • tRNA: Transfers amino acids
  • rRNA: Part of ribosome
• RNA Polymerase: Binds to DNA promoter, synthesizes RNA 5' to 3'

Translation Details

• Protein Synthesis Stages: Initiation, Elongation, Termination
• Codon Usage Map: 64 words, redundancy in genetic code
• tRNA: Anticodon complements mRNA codon

Differences: Prokaryotes vs Eukaryotes

• Prokaryotes:
  • Transcription and Translation can occur simultaneously
  • No introns, no nuclear envelope
• Eukaryotes:
  • Transcription in nucleus, translation in cytoplasm
  • mRNA splicing required
  • Single gene per mRNA

Summary

• Microbial Genetics: Study focus
• Replication: DNA duplication
• Transcription/Translation: Ongoing for protein synthesis
• Bacteria: Efficient gene expression without introns

Conclusion

• Contact: Questions via email or in class
• Next Topic: Regulation and mutations in bacteria