For this presentation – add to your notes all that is shown in
green font or with green background.
Bristol International Airport =
Pilots abort in torrential rain
Microsoft Zune
Frozen to music
How many letters are there in the English language?
How many words are there in the English language?
MAD
• *** 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
• ATTCGACT ATGCATCACG CTAAGTC
Where do we go from here?
• http://www.tvdsb.on.ca/westmin/science/sbi3a1/Genetics/Replicat.htm
MutationsMutation—mistake in the DNA that causes
errors in protein production.
Point mutation—mistake at a single point in the DNA.
*substitution—different base(s)*insertion—extra base(s)*deletion—lacking base(s)
SubstitutionDNA: ACC GTA CTA ATTmRNA:tRNA:Amino Acid:But is : ACC CTA CTA ATTAmino Acid:
The C has substitutedWhere there should be a G.
Point mutation con’t
Insertion
Should be: AAT TAG CCA GCGBut is : AAT ATA GCC AGC G
An extra base has been inserted where it should notbe causing a frameshift mutation.
What amino acids are formed?
Point mutation con’t
Deletion
Should be: ATA TTA TAG CGA But is: ATT TAT AGC GA
The A from the original strand of DNA is missingcausing a frameshift mutation.
What amino acids are formed?
Point mutation con’t
Chromosomal Mutations
• Deletion—part of a chrosome is missing.
• Duplication—creates extra copies of parts of chromomosomes.
• Inversion—reverse the direction of parts of the chrosomomes.
• Translocation—part 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 I’ve ever had!)
6th Block…show announcements!!!
http://ghsolycasts.com/announcements/English_Podcasts/English_Podcasts.html
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!
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