Contains Genes Genes specify proteins that determine traits Located in the nucleus of eukaryotes

NUCLEOTIDES : Monomers of nucleic acids composed of 3 parts: 1) Sugar : Deoxyribose (DNA) Ribose (RNA) 2) Phosphate Group 3) Nitrogen Base Two groups: Purines Adenine (A) & Guanine (G) Pyrimidines Thymine (T) & Cytosine (C)

BASE PAIRS BASE PAIRS: *Paired bases on inside of ladder. *Purines ( A & G) are paired to pyrimidines (T & C). *A is hydrogen-bonded to T * G is hydrogen-bonded to C

* Process by which DNA makes a copy of itself during cell division. *Four Enzymes Needed:

DNA HELICASE DNA HELICASE: Enzyme responsible for breaking apart the weak hydrogen bonds found in between two nucleotides of a DNA strand. DNA POLYMERASE: DNA POLYMERASE: Enzyme responsible for adding nucleotides to the new strand of DNA. HYDROGEN BONDS: Weak bonds that HYDROGEN BONDS: Weak bonds that join two complimentary nitrogen bases together. join two complimentary nitrogen bases together. *Count how many lines there are between A & T. Write this in your notes. Do the same for C & G. *

“The DNA looks the way it does on this paper because the bases and the bonds align. The second template is arranged according to its base pair. Cytosine goes with Guanine & Adenine goes with Thymine. The right side had to be flipped outside down so the phosphate & deoxyribose could be on the outside to serve as the “handrail.” The ladder had to be stable with handrails and the connected bases.” “The phosphate and the sugar needed to be on the outside of the DNA strand. So, we had to invert the complimentary bases to successfully make that happen. It is a double helix because the phosphate and sugar are on the outside so when it is traditionally twisted they create a double helix.”

1. DNA is unzipped by DNA Helicase enzyme. 2. DNA Helicase breaks the hydrogen bonds that hold the complimentary base pairs together. 3. The separation of the two single strands of DNA creates a ‘Y’ shape called a replication ‘fork’. Each separated strand will act as templates for making the new strands of DNA. *Watch first:

1a.) STRAND #1: Leading Strand oriented towards replication fork. 1b.) Primase enzyme binds to end of leading strand. 1c.) DNA polymerase enzyme adds one complimentary base nucleotides in the 5’ to 3’ direction at a time. This is called “continuous.” 2a.) STRAND #2: Lagging Strand oriented away from replication fork. 2b.) Primase enzyme binds at various points along lagging strand. 2c.) Chunks of DNA, called Okazaki fragments, are then added to the lagging strand in the 3’ to 5’ direction by DNA polymerase. This is called “discontinous.” 2d.) DNA ligase enzyme joins fills in gaps. Result of DNA Replication: Two DNA molecules consisting of one new and one old chain of nucleotides. Semi conservative: Half of the chain is original DNA and the other half is new.

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1. LABEL A PHOSPHATE, DEOXYRIBOSE, HYROGEN BONDS AND NITROGEN BASE THYMINE ON THE FIRST NUCLEOTIDE 2. STATE WHY DNA LOOKS THE WAY IT DOES ON YOUR PAPER- HOW IS THE SECOND TEMPLATE STRAND ARRANGED? EXPLAIN …