Dna And Variation Flashcards
What do polynucleotides look like when twisted
A double helix
What are the 2 types of variation
Continuous, discontinuous
What is continuous variation
Continuous data which shows a gradual change in data between two extremes with most values falling in the middle of that range.
What is discontinuous variation
Discontinuous data shows sharp differences in variation usually either/or categories with no in-betweens
What causes variation
Genetics and the enviournment
What are genetic factors
Eye colour blood group tongue rolling ability
What are environmental factors
Too much or too little food sunlight temperature
What role did chargaff play in the discovery of the structure of dna
He found out that DNA’s number of guanine units is equal to the number of cytosine units and the number of of adenine units is equal to the number of thymine units
What role did watson and crick play in the discovery of the structure of dna
They used the research from chargraff Franklin and Wilkins to create a 3D model of Dna which they found out looked like a double helix
What role did Wilkins and Franklin play in the discovery of the structure of dna
They got high resolution photos of chrystilised Dna fibres
Then they got the basic dimensions of the Dna strands and said that they were helical
