Chapter 16 The Molecular Basis of Inheritance

Question? u Traits are inherited on chromosomes, but what in the chromosomes is the genetic material?

Qualifications

For testing: u Name(s) of experimenters u Outline of the experiment u Result of the experiment and the importance of the result

Griffith

Griffith’s Experiment

Result

Problem

Avery, McCarty and MacLeod

Hershey- Chase 1952

Bacteria with Phages

Phage Components

Used Tracers

Experiment

Result DNA is the genetic material.

Picture Proof

Chargaff

Chargaff’s Rule

Why?

Watson and Crick

Rosalind Franklin

Book

DNA Composition

DNA Backbone

Nitrogen Bases

Chargaff’s Rule

Watson and Crick

Replication

Models for DNA Replication

Replication Models

Meselson - Stahl late 1950’s

Results

Replication - Preview

Origins of Replication

Prokaryotic

Eukaryotic Cells

DNA Elongation

Energy for Replication

Problem of Antiparallel DNA

Leading Strand

Lagging Strand

Priming

Okazaki Fragments

Enzymes

Other Proteins in Replication

Enzyme Summary

DNA Replication Error Rate

Reasons for Accuracy

DNA Repair

Example:

Xeroderma Pigmentosum Cancer Protected from UV

Thymine Dimers

Excision Repair

Problem - ends of DNA

Result

Telomeres

Implication

Telomerase

Comment

Summary u Know the Scientists and their experiments. u Why DNA is an excellent genetic material. u How DNA replicates. u Problems in replication.