DNA Structure

What is DNA? A type of nucleic acid that stores genetic information in all organisms Primary function of nucleic acids To store and transmit genetic info Provide instruction to build proteins Monomer: Nucleotides *A DNA molecule is a chain of repeating units

DNA Nucleotides These repeating units are composed of: A ring-shaped sugar (deoxyribose) A phosphate group 1 phosphorus with 4 oxygens A nitrogenous base

Nitrogenous Bases Adenine (A) Thymine (T) Cytosine (C) Guanine (G)

James Watson & Francis Crick Built the first DNA model using data from other scientists Double Helix (Two strands of DNA wind around each other like a twisted ladder) Rails – alternating deoxyribose and phosphate (aka sugar/phosphate backbone) Rungs/Steps – base pairs

Adenine pairs with Thymine A=T Cytosine pairs with Guanine C=G

*Sugar-phosphate Backbone

Task To use the materials given to create a model of a DNA molecule Model the sequence including complimentary base pairs: Sequence 1: T A C G T A Sequence 2: C G G T A C Sequence 3: A C G C T T Sequence 4: G A C C T A

Question In a sample of yeast DNA, 31.5% of the bases are Adenine (A). Predict the amounts of T, C and G.