*** had to carry info from one generation to the next *** heretiable traits had to be distinguishable *** had to be copy-able How to Extract DNA from Anything Living Complex, versatile structure ………Deoxyribonucleic acid. Describe the model that scientists developed to display the structure of DNA = twisted ladder, spiral staircase, double helix in which two strands or chains are wound around each other.
Each strand is made up of nucleotides = a series of molecules (monomers) 5-carbon sugar = deoxyribose 1-phosphate group--------- } nucleic acid (polymer) 1-nitrogenous base pair--- The base pairs are specifically paired as = A/T, C/G Adenine/Thymine and Guanine/Cytosine
The base pairs are specifically paired as = A/T, C/G Adenine/Thymine and Guanine/Cytosine Adenine and guanine are = Purines with two rings in their structure Thymine and cytosine are = Pyrimidines with one ring in their structure
The two strands are held together by (weak) hydrogen bonds between the nitrogenous base pairs. 1 human cell > nucleus > chromatin (DNA/histones) > super coiled nucleosomes > 1-2m of DNA Recall from the cell cycle the phase in which replication of DNA takes place = the S phase *An enzyme called DNA polymerase controls the replication process and triggers the separation of the hydrogen bonds between the 2 strands. The unzipped base pairs serve as a template and allow new strands to be synthesized. * Complementary
Mutations Mutationmistake in the DNA that causes errors in protein production.
Point mutationmistake at a single point in the DNA. *substitutiondifferent base(s) *insertionextra base(s) *deletionlacking base(s)
Substitution DNA: ACC GTA CTA ATT mRNA: tRNA: Amino Acid: But is : ACC CTA CTA ATT Amino Acid: The C has substituted Where there should be a G. Point mutation cont
Insertion Should be: AAT TAG CCA GCG But is : AAT ATA GCC AGC G An extra base has been inserted where it should not be causing a frameshift mutation. What amino acids are formed? Point mutation cont
Deletion Should be: ATA TTA TAG CGA But is: ATT TAT AGC GA The A from the original strand of DNA is missing causing a frameshift mutation. What amino acids are formed? Point mutation cont
Chromosomal Mutations Deletionpart of a chrosome is missing. Duplicationcreates extra copies of parts of chromomosomes. Inversionreverse the direction of parts of the chrosomomes. Translocationpart of one chrobreaksmosome off and attaches to another.
Significance of Mutations Most are neutral (no problem, no benefit) Some can cause dramatic effect on proteins created (big problem) (Can I use baby powder instead of flour for my cake?) But some may be very beneficial, and provide a source for genetic variability (I substituted chocolate for nuts, and this cake is the best Ive ever had!)
DNA Test Review Number of sugar molecules in DNA section containing 3 base pairs. Name of sugar found in DNA but not RNA. Carbohydrate subunit of a polysaccharide polymer. *tough one* CONTINUE REVIEWING WITH HOMEWORK…TEST ON friDAY!