Science Fact of the Day Scientists estimate that the human body is made up of around 10 trillion cells in total. Your skin makes up about 16 percent of your body weight. Of those billions of skin cells, between 30,000 and 40,000 of them fall off every hour. Over a 24-hour period, you lose almost a million skin cells.

___ ___ ___ Deoxyribonucleic Acid What type of biomolecule is DNA? What is the monomer? What type of bonds hold the bases together? ____________ bonds ____________ (5-carbon sugar) ____________ Nitrogenous ____________

CO: I will understand and describe the stages of DNA replication. LO: I will replicate the DNA strand I build yesterday with a partner. I will write about DNA replication.

Before a cell divides, it copies its DNA in a copying process called replication.cell

DNA replication DNA replication begins at a single point in the sequence and proceeds, in two directions, until the entire strand (chromosome) is replicated. This takes place in the nucleus.

A number of different enzymes (DNA polymerase, DNA ligase, primase) are used to match both sides of the DNA ladder to new base pairs in a 5’  3’ direction resulting in two identical DNA molecules.

Helicase is used to unzip the DNA molecule. DNA Polymerase brings nitrogen bases to the new strand.

Each strand of the DNA double helix has all of the information needed to recreate the other half (base pairing rules). Because each strand can be used to make the other strand, the strands are said to be complementary.

Because each strand after DNA replication is made from half the original strand and half new, it is referred to as the semi-conservative model of replication.

The complementary strand for AGGCTAAGTCGGTA is TCCGATTCAGCCAT…

Let’s give it a try!

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Your turn… What would the complementary strand to CGGAATTCGTCG be?

Summary: In 30 words, describe how the structure of DNA (complementary structure) makes its replication relatively easy.