Molecular Biology of the Gene - Key Concepts
Measles Overview
Caused by a contagious virus characterized by a red rash.
Nearly eradicated in the U.S. until outbreaks, like in California (2014).
Understanding of nucleic acids (DNA & RNA) is crucial for combating viruses.
Big Ideas in Genetic Material
Structure of genetic material
DNA replication
Flow of genetic information from DNA to RNA to protein
Genetics of viruses and bacteria
Scientific Experiments
Frederick Griffith (1928): Discovered transformation in bacteria; genetic material was inherited.
Hershey and Chase: Showed DNA is genetic material using phages; injected DNA in bacteria leads to new phages.
Nucleotides Structure
DNA & RNA are polymers of nucleotides, which comprise:
Nitrogenous base
Five-carbon sugar
Phosphate group
DNA contains adenine (A), cytosine (C), thymine (T), and guanine (G).
RNA contains uracil (U) instead of thymine and ribose instead of deoxyribose.
DNA Structure
Double-helix model proposed by Watson and Crick, featuring complementary base pairing (A-T, G-C).
DNA replication is semiconservative; each old strand serves as a template for a new strand.
Flow of Genetic Information
Transcription: DNA is used to synthesize RNA.
Translation: RNA is translated into proteins.
Genetic code composed of codons (triplet codes) translates nucleotide sequence into amino acids.
Mutations
Changes in genetic information can occur due to errors during replication or by physical/chemical mutagens.
Viruses
Consist of nucleic acid in a protein coat.
Can enter lytic (active replication) or lysogenic (integration into host DNA) cycles.
Emerging viruses (e.g., HIV, Coronavirus) pose health threats.
Prions
Infectious proteins causing diseases by inducing misfolding of normal proteins.
Key Understanding Goals
Summarize Griffith’s, Hershey’s, and Chase’s experiments on DNA as genetic material.
Distinguish structures of DNA and RNA.
Explain DNA structure's role in replication.
Outline the DNA replication process.