dna structure
DESCRIPTION
(This slideshare is being made for practice only - do not use this for educational purposes. Original Source, FCPS ESOL department.)TRANSCRIPT
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DNA Structure• DNA: Deoxyribonucleic acid• Each chromosome is made of one
piece of DNA46 chromosomes = 46 pieces of DNA
• DNA:– 2 strands connected– Shape of a twisted ladder– The twisted ladder is called a
DOUBLE HELIX
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Function of DNA:
- Stores genetic information: genetic information makes you what you are
- Controls all cell and body activities
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Chromosome Structure Section 12-2
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Nucleotides: Basic building blocks of DNA
Nucleotides are made up of:
• Deoxyribose: a sugar
• Phosphate• Nitrogen Base:
– Adenine = A
– Guanine = G
– Cytosine = C
– Thymine = T
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Nucleotides and Pairing: A-T C-G
The sugar and phosphate make the sides or rails of the double helix (ladder)
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Structure of DNASection 12-1
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DNA complementary strands
• The 2 strands of DNA are represented by the sequence of nitrogen bases
A T C G A A C G T T A
T A G C T T G C A A T
• Write the complementary DNA strand:
A T C G G G T T A A C G T A T C C
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The People Behind
1. 1949: Erwin Chargaff discovers the rules of base pairing
A-T C-G
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2. 1952: Rosalind Franklin determined that the DNA molecule was a coiled spiral.
They used a technique called X-ray diffraction
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3. 1953: James Watson (USA) and Francis Crick (UK) determine the exact structure of DNA.
• Received the Nobel Prize in 1962
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Nucleic Acids
• Are made of: C (carbon), H (hydrogen),
O (oxygen), N (nitrogen), P (phosphates).