Topic 3: The Molecular Basis Of Inheritance Flashcards
Components of chromosomes
DNA and Protein
Which component of chromosomes is a stronger candidate?
Protein
Genetic material needs to have what characteristics?
- Contain information
- Be easy to copy
- Be variable to account for diversity between species
The role of DNA in heredity was first discovered by studying what?
Bacteria and viruses
What experiment gave evidence that DNA can transform bacteria?
Griffith experiment (1928)
Transformation
The genetic alteration of a cell due to uptake and incorporation of exogenous (foreign) DNA
Griffith experiment process
He mixed 2 strains of the bacterium Streptococcus pneumoniae (a heat-inactivated pathogenic strain with living bacteria of a harmless (non-pathogenic) strain)
=> some living cells became pathogenic
What was the substance found in Griffiths experiment later found to be?
Transforming substance -> DNA
What experiment gave evidence that viral DNA can program cells?
Hershey and Chase experiments (1952)
Studies of viruses that infect bacteria (bacteriophages)
What did Erwin Chargraff report?
DNA composition varies between species
=> evidence of diversity
What method was used to study the molecular structure of DNA ORIGINALLY?
Rosalind Franklin & Maurice Wilkins
X-ray crystallography
Why was building a structural model of DNA so important?
To determine how DNA structure accounts for its role in inheritance
What was Watson and Crick’s role in the model of DNA discovery?
Produced the double-helical model for DNA structure
DNA was made up of 2 strands forming a double helix based on Franklin’s X-ray crystallographic images
DNA structure
2 antiparallel sugar-phosphate backbones
The nitrogenous bases pairs are in the molecule’s interior
(A & T, G & C)
Explains Chargraff’s rule
