(REP) DNA Replication Lesson

DNA Replication Lesson

A DNA molecule consists of two strands of nucleotides held together by the hydrogen bonds between the nitrogen bases on each DNA strand. Therefore the adenine (A) on one nucleotide pairs with the thymine (T) on the other nucleotide. As the bases pair up, the DNA molecule begins to form a shape that resembles a spiral staircase or twisted ladder. Recall that this shape is called the double helix. When a DNA molecule replicates, it produces two new strands of DNA that are identical to the original DNA molecule.

 

Watch the following video, How DNA Replicates.

 

 

Enzymes help our DNA to replicate or make a copy.  The enzyme helicase unwinds or unzips the DNA molecule. The two strands that make up the double helix are separated. A binding protein attaches to the two strands and keeps them apart. This allows the nucleotides that are floating around freely in the nucleus to bind with the nucleotides on each strand. A complex group of enzymes called DNA polymerase helps build new strands of DNA. As DNA polymerase attaches and moves along the original strand of DNA, it helps the nucleotides from within the nucleus bind to the DNA template according to the base pairing rule. The two new DNA strands are identical to the original strands. There are four strands of DNA, two original strands and two new strands. Each DNA molecule now has an original strand and one new strand.

 

 

A cell replicates its DNA every time it gets ready to divide into two new cells. DNA replication is a process that helps ensure that each human cell has the genetic information necessary for life and reproduction.

 

Complete the following as a self-assessment of your knowledge.

 

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