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Section12.2. 1. Structure of DNA. 2. Components of DNA. 3. DNA (deoxyribonucleic acid) is a nucleic acid made up of nucleotides joined into long strands by covalent bonds. 2. Nucleotides. 3. Nucleotides are building blocks of nucleic acids 4. Nucleotides: 3 parts
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Section12.2 1. Structure of DNA
2. Components of DNA • 3. DNA (deoxyribonucleic acid) is a nucleic acid made up of nucleotides joined into long strands by covalent bonds
2. Nucleotides • 3. Nucleotides are building blocks of nucleic acids • 4. Nucleotides: 3 parts • 5. 5-carbon sugar: deoxyribose • 5. Phosphate group • 5. Nitrogenous base • 4. 4 Nitrogenous bases (contain Nitrogen): • 5. Adenine • 5. Guanine • 5. Thymine • 5. Cytosine
2. Bonds…James Bonds…jk • 3. Nucleotides joined by covalent bonds • 4. Forms between sugar of one nucleotide and phosphate group of the next. 3. Nitrogenous bases 4. Stick out sideways from the nucleotide chain 4. Nucleotides can be joined together in a number of different ways 4. Any base sequence is possible 4. That’s what makes us so different! 4. Have a special chemical structure that is especially good at absorbing UV light
Stop and Write(2-5 min.) • 1. What are the 3 components of a nucleotide? • 2. What are the four nitrogenous bases? • 3. Do you think excessive UV light could damage your DNA? How?
2. Erwin Chargaff • 3. Austrian-American biochemist • 3. Discovered that % of: • 4. Adenine [A]= Thymine [T] • 4. Guanine[G]= Cytosine [C] P. 345 Analyzing data #1-4 (5 min.)
2. Double- helix • 3. Explains Chargaff’s rule • 3. Antiparallel strands • 4. DNA runs in opposite directions 3. Hydrogen bonds 4. Both strands of DNA are held together by H bonds between nitrogenous bases (A and T) and (G and C). 3. Base pairing 4. A always lines up perfectly with T 4. G always lines up perfectly with C
Photo credits • http://www.google.com/imgres?imgurl=http://katienelson4b.edublogs.org/files/2011/11/nucleotide-1p9gib5.jpg&imgrefurl=http://katienelson4b.edublogs.org/tag/nucleotide/&h=446&w=250&sz=75&tbnid=lfIfHbGruEmCDM:&tbnh=90&tbnw=50&prev=/search%3Fq%3Ddna%2Bnucleotides%26tbm%3Disch%26tbo%3Du&zoom=1&q=dna+nucleotides&usg=__lwz4o6W-xrLEn1zPP2NlGTfu7n0=&docid=_Box7VZ7RoXcCM&hl=en&sa=X&ei=KbChUNq2JJTAyQG9voDwBA&sqi=2&ved=0CDMQ9QEwAg&dur=6797 • http://4.bp.blogspot.com/-blHHFOAeRHw/Tbcr4yajYgI/AAAAAAAABTk/wQ9OpgOLhrA/s1600/Rosalind%2BFranklin%2B.jpg • http://lebbeuswoods.files.wordpress.com/2010/08/watson-crick-2.jpg