DNA Structure and Replication Honors Biology 2013

DNA Deoxyribonucleic acid – Genes are composed of this material – Instructions for the cell on how to make proteins – Double helix structure ( figured out by James Watson and Francis Crick through Rosalind Franklin’s x-ray crystallography) – Nucleic acid What are the monomers of nucleic acids???

DNA Deoxyribonucleic acid – Genes are composed of this material – Instructions for the cell on how to make proteins – Double helix structure ( figured out by James Watson and Francis Crick through Rosalind Franklin’s x-ray crystallography) – Nucleic acid What are the monomers of nucleic acids??? Nucleotides!

DNA DNA is made up of nucleotides – A nucleotide consists of 3 parts A 5 carbon sugar (deoxyribose) A phosphate group A nitrogenous base – Two types » Purines (adenine and guanine) have two rings » Pyrimadines (thymine and cytosine) have one ring

DNA DNA has two sugar-phosphate strands that are the backbone and the nitrogenous bases make up the “rungs” of the ladder

DNA Chargaff’s Rule- there are similar percentages of adenine and thymine, and cytosine and guanine. This is because adenine binds to thymine and cytosine binds to guanine through hydrogen bonding---This is called base-pairing.

Adenine to Thymine has 2 hydrogen bonds between them Cytosine to Guanine has 3 hydrogen bonds between them.

What would be the order of the other side of this DNA molecule?? AAGCTACCAAGCTACC

A-T G-C C-G T-A A-T C-G

DNA The order of nitrogenous bases in DNA determines the order of amino acids in a protein.

DNA Replication Prokaryotic DNA is found in their cytoplasm Eukaryotic DNA is found in the nucleaus of the cell. When a cell divides, it must make an exact copy of its DNA so both cells have complete sets. This happens in the S phase of interphase of the cell cycle.

DNA Replication During replication, DNA double helix is separated. Each strand acts as a template and produces two new complementary strands.

DNA Replication Replication begins at sites on the DNA molecule called origins of replication. Helicase unwinds the DNA molecule to produce two separate strands. Primase makes a short strand of RNA that is used to start synthesis of the complementary strand. DNA polymerase adds new nucleotides to the new strand. Nuclease checks and repairs the DNA for damage or mutations.

DNA Replication videos hill.com/sites/ /student_view0/cha pter3/animation__dna_replication__quiz_1_.ht ml d-DNA-Replication