DNA Replication

By Brady Young

The DNA molecule starts out replication in a double helix. DNA contains genetic material and holds the code for what you are. It’s nucleotides are composed of sugars, phosphates, and nitrogen bases. The nitrogen bases in the helix are held together by hydrogen bonds.

Hel

icas

e

The first step of DNA replication begins with the enzyme helicase. Helicase breaks apart the hydrogen bonds that keep the nitrogen bases together. This process resembles unzipping a zipper.

Hel

icas

e

The first step of DNA replication begins with the enzyme helicase. Helicase breaks apart the hydrogen bonds that keep the nitrogen bases together. This process resembles unzipping a zipper.

Hel

icas

e

The first step of DNA replication begins with the enzyme helicase. Helicase breaks apart the hydrogen bonds that keep the nitrogen bases together. This process resembles unzipping a zipper.

Hel

icas

e

The first step of DNA replication begins with the enzyme helicase. Helicase breaks apart the hydrogen bonds that keep the nitrogen bases together. This process resembles unzipping a zipper.

Hel

icas

e

The first step of DNA replication begins with the enzyme helicase. Helicase breaks apart the hydrogen bonds that keep the nitrogen bases together. This process resembles unzipping a zipper.

Hel

icas

e

The first step of DNA replication begins with the enzyme helicase. Helicase breaks apart the hydrogen bonds that keep the nitrogen bases together. This process resembles unzipping a zipper.

Hel

icas

e

The first step of DNA replication begins with the enzyme helicase. Helicase breaks apart the hydrogen bonds that keep the nitrogen bases together. This process resembles unzipping a zipper.

Hel

icas

e

The first step of DNA replication begins with the enzyme helicase. Helicase breaks apart the hydrogen bonds that keep the nitrogen bases together. This process resembles unzipping a zipper.

Hel

icas

e

The first step of DNA replication begins with the enzyme helicase. Helicase breaks apart the hydrogen bonds that keep the nitrogen bases together. This process resembles unzipping a zipper.

Hel

icas

e

The first step of DNA replication begins with the enzyme helicase. Helicase breaks apart the hydrogen bonds that keep the nitrogen bases together. This process resembles unzipping a zipper.

Hel

icas

e

The first step of DNA replication begins with the enzyme helicase. Helicase breaks apart the hydrogen bonds that keep the nitrogen bases together. This process resembles unzipping a zipper.

The two newly separated strands can then separate from each other.

The two newly separated strands can then separate from each other.

The enzyme DNA Polymerase lll then reads the leading strand and adds the 5’ phosphate end of a nucleotide to the 3’end continuously. This enlongates towards the replication fork.

The enzyme DNA Polymerase lll then reads the leading strand and adds the 5’ phosphate end of a nucleotide to the 3’end continuously. This enlongates towards the replication fork.

The enzyme DNA Polymerase lll then reads the leading strand and adds the 5’ phosphate end of a nucleotide to the 3’end continuously. This enlongates towards the replication fork.

The enzyme DNA Polymerase lll then reads the leading strand and adds the 5’ phosphate end of a nucleotide to the 3’end continuously. This enlongates towards the replication fork.

The enzyme DNA Polymerase lll then reads the leading strand and adds the 5’ phosphate end of a nucleotide to the 3’end continuously. This enlongates towards the replication fork.

On the lagging strand of DNA, an RNA primer marks a starting point in which DNA Polymerase ll adds nucleotides to create okazaki fragments.

On the lagging strand of DNA, an RNA primer marks a starting point in which DNA Polymerase ll adds nucleotides to create okazaki fragments.

On the lagging strand of DNA, an RNA primer marks a starting point in which DNA Polymerase ll adds nucleotides to create okazaki fragments.

DNA Polymeraes l then turns the RNA into DNA when DNA Polymerase ll comes to the RNA primer from the last fragment.

To finalize the process, DNA ligase then forms a phophodiesterbond to complete the connection of okazaki fragments.

This completes the last step of DNA replication and there are now two new complementary strands of DNA.

DNA Mutations

DNA mutations occur when two nitrogen bases pair with the wrong partner, as you can see with guanine and adenine. This can cause defective DNA which may prevent an embryo from surviving to birth.

Telomeres

Telomeres are segments of DNA that are in eukaryotic cells. They are repeated DNA fragments that include the sequence 5’-TTAGG-3’ for the nitrogen bases. Telomeres are located at the ends of chromosomes. Every time a cell divides, the telomeres shorten. They then become too short for the cell to divide and it dies. This death of telomeres leads to faster aging and higher risks of cancer and death.

DNA Cloning

The cloning of DNA is very useful in our modern society. Cloning is a method in molecular biology that is used to multiply DNA molecules. This multiplication is done through DNA replication. This can aid in situations such as police and crime scenes. Transplant cells can replace damaged cells inside the body.