1. Bellwork: Mon: Nov 22,2010 2. Which bases are which?
A DNA molecule separates, and the sequence GCGAATTCG occurs in one strand. Write out the original and complimentary Strand: GCGAATTCG
2. Which bases are which?
Draw them. How do you know:
3. What are these colored genes called? (hint: think of the video we watched “What Darwin Never Knew”)

2. Eukaryotic Chromosome Structure
Nucleosome
DNA double helix
Coils
Supercoils
Eukaryotic chromosomes contain DNA wrapped around proteins called histones. The strands of nucleosomes are tightly coiled and supercoiled to form chromosomes.
Histones

3. DNA Replication
Replication: before a cell divides, it duplicates its DNA so each new cell will have a complete set of DNA.
DNA molecule separates into two strands, then produces two new complementary strands

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DNA Replication
New Strand
Original strand
Nitrogen Bases
Growth
Growth
During DNA replication, the DNA molecule produces two new complementary strands. Each strand of the double helix of DNA serves as a template for the new strand.
Replication Fork
Replication Fork
DNA Polymerase
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DNA Replication
How Replication Occurs
DNA replication is carried out by enzymes that “unzip” a molecule of DNA.
Hydrogen bonds between base pairs are broken and the two strands of DNA unwind.
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12–2
The structure that may play a role in regulating how genes are “read” to make a protein is the
coil.
histone.
nucleosome.
chromatin.
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