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12.1 DNA: STRUCTURE & FUNCTION
DNA—deoxyribonucleic acid
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BACKGROUND INFO--NUCLEUS
-NUCLEUS is control center of the cell— -NUCLEUS controls all cell activities including: cell reproduction & heredity storage of genetic information DNAGENESCHROMOSOMESNUCLEUSCELLS
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BACKGROUND INFO--PROTEINS
-building blocks for every structure in your body -control chemical processes in the cell
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DNA FUNCTION DNAStorage/Transmit genetic information DNA’s primary function – code for PROTEINS
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DNA BLUEPRINT of LIFE—
ALL body cells (except sex cells) have same copies of DNA to produce protein structures…. all 70 BILLION of them!! DNA is found in other organelles— mitochondria & chloroplasts
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DNA STRUCTURE 1953—James Watson & Francis Crick discovered
-double helix = twisted staircase -unwound resembles a ladder
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DNA STRUCTURE
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DNA Double Helix Nitrogenous Base (A,T,G or C) “Rungs of ladder” “Legs of ladder” Phosphate & Sugar Backbone copyright cmassengale
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NUCLEOTIDES -repeating sub-units of DNA
1 nucleotide = 1 sugar, 1 phosphate, 1 base
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NUCLEOTIDES stack on top of each other to form sides of DNA
NUCLEOTIDE INFO: 1 nucleotide : 1 sugar, 1 phosphate 1 base NUCLEOTIDES stack on top of each other to form sides of DNA 1side of DNA upside down--“anti-parallel” 2 bases attached with hydrogen bonds
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-A = Adenine -G = Guanine NITROGENOUS BASES
PURINES – 2 rings of C and N -A = Adenine -G = Guanine *2 rings--each has 2 n’s *both end in “nine” Double ring has nine sides
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T=Thymine C = Cytosine NITROGENOUS BASES
PYRIMIDINE – single ring of C and N T=Thymine C = Cytosine *1 ring--each has 1 n* *both have a “y” – so does pyrimidine
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DNA STRUCTURE *CHARGAFF’S RULE THYMINE = ADENINE GUANINE = CYTOSINE
CREATE: memory device for pairing nitrogenous bases T A G C
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DNA STRUCTURE P O 1 2 3 4 5 P O 1 2 3 4 5 G C T A copyright cmassengale
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ANTIPARALLEL SET 2 PENCILS PARALLEL TO EACH OTHER
--POINT 1ST PENCIL UP --POINT 2ND PENCIL DOWN = ANTI-PARALLEL One strand of DNA runs from 5’ to 3’ (sugars) The other strand runs in opposite direction - 3’ to 5’ (sugars)
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Nucleotides THINK – PAIR – SHARE
-What are the repeating units in DNA called? Nucleotides -What 3 things make up a DNA nucleotide? Sugar Phosphate Nitrogen containing base
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NITROGENOUS BASE PAIR RULES
CREATE a matching (complementary) DNA sequence for the following strand: A T G A A G T T T T T GG C T G G C T A G
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DNA: Blueprint of Life
-ANALYZE why DNA is called the “BLUEPRINT of LIFE” -every cell in your body has the same copies of DNA –pattern to produce protein structures
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NUCLEUS: Control Center of the Cell
-INFER why the nucleus is called the “CONTROL CENTER” of the cell -controls all activities of the cell including cellular reproduction and heredity
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APPLY: COMPLETE the DNA CONCEPT MAP
nucleotides twisted ladder produce proteins double helix nitrogenous base phosphate group Watson & Crick deoxyribose guanine adenine thymine cytosine 1953
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MODEL structures of DNA by labeling & coloring
SUGAR--pink PHOSPHATE--green CYTOSINE--grey GUANINE--orange THYMINE--blue ADENINE--yellow
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copyright cmassengale
NUCLEOTIDE O=P-O O Phosphate Group N Nitrogenous base (A, G, C, or T) O CH2 O C1 C4 C3 C2 5 Sugar (deoxyribose) copyright cmassengale
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