DNA Deoxyribonucleic Acid D – Deoxyribo N – Nucleic A – Acid

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DNA Structure Nucleotide Nucleotide –The monomer of DNA –Basic unit –Consists of 3 parts

Nucleotide- Part 1 (p197) 5 carbon sugar 5 carbon sugar –Deoxyribose

Nucleotide- Part 2 (p197) Phosphate group Phosphate group

Nucleotide- Part 3 (p197) Nitrogenous bases- 4 different (p 198) Nitrogenous bases- 4 different (p 198) –Purines adenine (A) adenine (A) guanine (G) guanine (G)

Nucleotide- Part 3 (p197) Nitrogenous bases- 4 different (p 198) Nitrogenous bases- 4 different (p 198) –Pyrimidines thymine (T) thymine (T) cytosine (C) cytosine (C)

Nucleotide Model Model Pentagon = sugar Pentagon = sugar Circle = phosphate group Circle = phosphate group Square = nitrogen base Square = nitrogen base

Shape of DNA (p199) Double helix Double helix –2 spirals wrapped around each other

Ladder Model of DNA (p199) “Uprights”- “Uprights”- –5 carbon sugar & phosphate “Rungs”- “Rungs”- –Nitrogenous base pairs –Base pairs held together by hydrogen bonds –A with T –C with G P * D - C ~ G- D D - C ~ G- D * * * * P P P P * * * * D - T ~ A- D D - T ~ A- D * * * * P P P P * * * * D- T ~ A - D D- T ~ A - D * * * * P P P P * * * * D - A ~ T- D D - A ~ T- D * * * * P P P P * * * * D - C ~ G- D D - C ~ G- D * * * * P P P P * * * * D - G ~ C- D D - G ~ C- D * * P P

DNA Replication (p 201) Process in which DNA makes exact copies of itself in the nucleus. 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. DNA molecule “unzips” where the hydrogen bonds hold the base pairs together in the rungs of the ladder. Helicases- enzymes that break hydrogen bonds Helicases- enzymes that break hydrogen bonds

DNA Replication (p 201) New nucleotides attach, one by one, to the appropriate exposed bases of the DNA strands 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 DNA polymerases- enzymes that add the bases to original strand P * D - C ~ G- D D - C ~ G- D * * * * P P P P * * * * D - T ~ A- D D - T ~ A- D * * * * P P P P * D - T D - T * P * D - A D - A * P * D - C D - C * P * D - G D - G

DNA Replication (p 201) The result is 2 DNA molecules from 1 The result is 2 DNA molecules from 1

DNA Replication (p 201) Each molecule is identical to each other and the original. Each molecule is identical to each other and the original.

DNA Replication (p 201) Semi-conservative Replication Semi-conservative Replication –Each newly formed DNA molecule is made up of one strand from the original and one strand that is new.