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DNA. D eoxyribo n ucleic A cid D – Deoxyribo N – Nucleic A – Acid. All Images- Clip Art. DNA Structure. Nucleotide The monomer of DNA Basic unit Consists of 3 parts. Nucleotide- Part 1 (p197). 5 carbon sugar Deoxyribose. Nucleotide- Part 2 (p197). Phosphate group.
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DNA • Deoxyribonucleic Acid • D – Deoxyribo • N – Nucleic • A – Acid
DNA Structure • Nucleotide • The monomer of DNA • Basic unit • Consists of 3 parts
Nucleotide- Part 1 (p197) • 5 carbon sugar • Deoxyribose
Nucleotide- Part 2 (p197) • Phosphate group
Nucleotide- Part 3 (p197) • Nitrogenous bases- 4 different (p 198) • Purines • adenine (A) • guanine (G)
Nucleotide- Part 3 (p197) • Nitrogenous bases- 4 different (p 198) • Pyrimidines • thymine (T) • cytosine (C)
Model Pentagon = sugar Circle = phosphate group Square = nitrogen base Nucleotide
Shape of DNA (p199) • Double helix • 2 spirals wrapped around each other
“Uprights”- 5 carbon sugar & phosphate “Rungs”- Nitrogenous base pairs Base pairs held together by hydrogen bonds A with T C with G P * D - C ~ G- D * * P P * * D - T ~ A- D * * P P * * D- T ~ A - D * * P P * * D - A ~ T- D * * P P * * D - C ~ G- D * * P P * * D - G ~ C- D * P Ladder Model of DNA (p199)
DNA Replication (p 201) • Process in which DNA makes exact copies of itself in the nucleus.
DNA Replication (p 201) • DNA molecule “unzips” where the hydrogen bonds hold the base pairs together in the rungs of the ladder. • Helicases- enzymes that break hydrogen bonds
New nucleotides attach, one by one, to the appropriate exposed bases of the DNA strands DNA polymerases- enzymes that add the bases to original strand P * D - C ~ G- D * * P P * * D - T ~ A- D * * P P * D - T * P * D - A * P * D - C * P * D - G DNA Replication (p 201)
DNA Replication (p 201) • The result is 2 DNA molecules from 1
DNA Replication (p 201) • Each molecule is identical to each other and the original.
DNA Replication (p 201) • Semi-conservative Replication • Each newly formed DNA molecule is made up of one strand from the original and one strand that is new.