DNA ReplicationBy: Danielle Bowser

T

T

T

A

A

G

A

A

A

T

T

G

G

G

C

C

C

C

DNA Basics

Lets start with the basics! DNA stands for deoxyribonucleic acid and it is made up of phosphates, sugars, and nitrogen bases. DNA is a type of nucleic acid (polymer) made up of many nucleotides (monomers) through dehydration synthesis. DNA is generally known for it’s double helix feature.

A

G

C

T

Nucleotide

Sugar

Phosphate

Adenine

Guanine

Cytosine

Thymine

Key

Nitrogen Bases

T

T

T

A

A

G

A

A

A

T

T

G

G

G

C

C

C

C

A

G

C

T

Nucleotide

Sugar

Phosphate

Adenine

Guanine

Cytosine

Thymine

Key

DNA Replication

DNA is replicated during the interphase step of mitosis. To start, the enzyme DNA Helicase “unzips” the double helix at the origin of replication (certain sequence of nucleotides-generally Adenine and Thymine-were replication starts).

DNA Helicase

T

T

T

A

A

G

A

A

A

T

T

G

G

G

C

C

C

C

A

G

C

T

Nucleotide

Sugar

Phosphate

Adenine

Guanine

Cytosine

Thymine

Key

DNA Replication

DNA is replicated during the interphase step of mitosis. To start, the enzyme DNA Helicase “unzips” the double helix at the origin of replication (certain sequence of nucleotides-generally Adenine and Thymine-were replication starts).

DNA Helicase

T

T

T

A

A

G

A

A

A

T

T

G

G

G

C

C

C

C

A

G

C

T

Nucleotide

Sugar

Phosphate

Adenine

Guanine

Cytosine

Thymine

Key

DNA Replication

DNA is replicated during the interphase step of mitosis. To start, the enzyme DNA Helicase “unzips” the double helix at the origin of replication (certain sequence of nucleotides-generally Adenine and Thymine-were replication starts).

DNA Helicase

T

T

T

A

A

G

A

A

A

T

T

G

G

G

C

C

C

C

A

G

C

T

Nucleotide

Sugar

Phosphate

Adenine

Guanine

Cytosine

Thymine

Key

DNA Replication

DNA is replicated during the interphase step of mitosis. To start, the enzyme DNA Helicase “unzips” the double helix at the origin of replication (certain sequence of nucleotides-generally Adenine and Thymine-were replication starts).

DNA Helicase

T

T

T

A

A

G

A

A

A

T

T

G

G

G

C

C

C

C

A

G

C

T

Nucleotide

Sugar

Phosphate

Adenine

Guanine

Cytosine

Thymine

Key

DNA Replication

DNA is replicated during the interphase step of mitosis. To start, the enzyme DNA Helicase “unzips” the double helix at the origin of replication (certain sequence of nucleotides-generally Adenine and Thymine-were replication starts).

DNA Helicase

T

T

T

A

A

G

A

A

A

T

T

G

G

G

C

C

C

C

A

G

C

T

Nucleotide

Sugar

Phosphate

Adenine

Guanine

Cytosine

Thymine

Key

DNA Replication

DNA is replicated during the interphase step of mitosis. To start, the enzyme DNA Helicase “unzips” the double helix at the origin of replication (certain sequence of nucleotides-generally Adenine and Thymine-were replication starts).DNA

Helicase

T

T

T

A

A

G

A

A

A

T

T

G

G

G

C

C

C

C

A

G

C

T

Nucleotide

Sugar

Phosphate

Adenine

Guanine

Cytosine

Thymine

Key

DNA Replication

DNA is replicated during the interphase step of mitosis. To start, the enzyme DNA Helicase “unzips” the double helix at the origin of replication (certain sequence of nucleotides-generally Adenine and Thymine-were replication starts).

DNA Helicase

T

T

T

A

A

G

A

A

A

T

T

G

G

G

C

C

C

C

A

G

C

T

Nucleotide

Sugar

Phosphate

Adenine

Guanine

Cytosine

Thymine

Key

DNA Replication

DNA is replicated during the interphase step of mitosis. To start, the enzyme DNA Helicase “unzips” the double helix at the origin of replication (certain sequence of nucleotides-generally Adenine and Thymine-were replication starts).

DNA Helicase

T

T

T

A

A

G

A

A

A

T

T

G

G

G

C

C

C

C

A

G

C

T

Nucleotide

Sugar

Phosphate

Adenine

Guanine

Cytosine

Thymine

Key

DNA Replication

DNA is replicated during the interphase step of mitosis. To start, the enzyme DNA Helicase “unzips” the double helix at the origin of replication (certain sequence of nucleotides-generally Adenine and Thymine-were replication starts).

DNA Helicase

T

T

T

A

A

G

A

A

A

T

T

G

G

G

C

C

C

C

A

G

C

T

Nucleotide

Sugar

Phosphate

Adenine

Guanine

Cytosine

Thymine

Key

DNA Replication

DNA is replicated during the interphase step of mitosis. To start, the enzyme DNA Helicase “unzips” the double helix at the origin of replication (certain sequence of nucleotides-generally Adenine and Thymine-were replication starts).

G

A

A

A

T

T

G

G

C

A

G

C

T

Nucleotide

Sugar

Phosphate

Adenine

Guanine

Cytosine

Thymine

Key

DNA Replication

Single stranded proteins attach to the DNA strands to keep them from kinking or folding up on themselves. Now we are going to look at the leading stand.

T

T

T

A

A

G

C

C

C

A

G

C

T

Nucleotide

Sugar

Phosphate

Adenine

Guanine

Cytosine

Thymine

Key

DNA Replication

DNA polymerase III reads the DNA strands from 3 prime to 5 prime and adds complementary nucleotides in the 5 prime to 3 prime direction. The complementary bases are Adenine/Thymine and Guanine/Cytosine. Nucleotides are added going towards the replication fork (point where the helicase is splitting the nucleotides).

3’

5’DNA

Polymerase III

Leading Strand

T

T

T

A

A

G

C

C

C

A

G

C

T

Nucleotide

Sugar

Phosphate

Adenine

Guanine

Cytosine

Thymine

Key

DNA Replication

DNA polymerase III reads the DNA strands from 3 prime to 5 prime and adds complementary nucleotides in the 5 prime to 3 prime direction. The complementary bases are Adenine/Thymine and Guanine/Cytosine. Nucleotides are added going towards the replication fork (point where the helicase is splitting the nucleotides).

3’

5’

Leading Strand

T

T

T

A

A

G

C

C

C

DNA Polymerase

III

A

A

G

C

T

Nucleotide

Sugar

Phosphate

Adenine

Guanine

Cytosine

Thymine

Key

DNA Replication

DNA polymerase III reads the DNA strands from 3 prime to 5 prime and adds complementary nucleotides in the 5 prime to 3 prime direction. The complementary bases are Adenine/Thymine and Guanine/Cytosine. Nucleotides are added going towards the replication fork (point where the helicase is splitting the nucleotides).

3’

5’

Leading Strand

T

T

T

A

A

G

C

C

C

DNA Polymerase

III

A

A

G

C

T

Nucleotide

Sugar

Phosphate

Adenine

Guanine

Cytosine

Thymine

Key

DNA Replication

DNA polymerase III reads the DNA strands from 3 prime to 5 prime and adds complementary nucleotides in the 5 prime to 3 prime direction. The complementary bases are Adenine/Thymine and Guanine/Cytosine. Nucleotides are added going towards the replication fork (point where the helicase is splitting the nucleotides).

3’

5’

Leading Strand

T

T

T

A

A

G

C

C

C

A

DNA Polymerase

III

G

A

A

G

C

T

Nucleotide

Sugar

Phosphate

Adenine

Guanine

Cytosine

Thymine

Key

DNA Replication

DNA polymerase III reads the DNA strands from 3 prime to 5 prime and adds complementary nucleotides in the 5 prime to 3 prime direction. The complementary bases are Adenine/Thymine and Guanine/Cytosine. Nucleotides are added going towards the replication fork (point where the helicase is splitting the nucleotides).

3’

5’

Leading Strand

T

T

T

A

A

G

C

C

C

A

DNA Polymerase

III

G

A

A

G

C

T

Nucleotide

Sugar

Phosphate

Adenine

Guanine

Cytosine

Thymine

Key

DNA Replication

DNA polymerase III reads the DNA strands from 3 prime to 5 prime and adds complementary nucleotides in the 5 prime to 3 prime direction. The complementary bases are Adenine/Thymine and Guanine/Cytosine. Nucleotides are added going towards the replication fork (point where the helicase is splitting the nucleotides).

3’

5’

Leading Strand

T

T

T

A

A

G

C

C

C

A

DNA Polymerase

III

T

G

A

A

G

C

T

Nucleotide

Sugar

Phosphate

Adenine

Guanine

Cytosine

Thymine

Key

DNA Replication

DNA polymerase III reads the DNA strands from 3 prime to 5 prime and adds complementary nucleotides in the 5 prime to 3 prime direction. The complementary bases are Adenine/Thymine and Guanine/Cytosine. Nucleotides are added going towards the replication fork (point where the helicase is splitting the nucleotides).

3’

5’

Leading Strand

T

T

T

A

A

G

C

C

C

A

DNA Polymerase

III

G

C

T

G

A

A

G

C

T

Nucleotide

Sugar

Phosphate

Adenine

Guanine

Cytosine

Thymine

Key

DNA Replication

DNA polymerase III reads the DNA strands from 3 prime to 5 prime and adds complementary nucleotides in the 5 prime to 3 prime direction. The complementary bases are Adenine/Thymine and Guanine/Cytosine. Nucleotides are added going towards the replication fork (point where the helicase is splitting the nucleotides).

3’

5’

Leading Strand

T

T

T

A

A

G

C

C

C

A

DNA Polymerase

III

G

C

T

G

A

A

G

C

T

Nucleotide

Sugar

Phosphate

Adenine

Guanine

Cytosine

Thymine

Key

DNA Replication

DNA polymerase III reads the DNA strands from 3 prime to 5 prime and adds complementary nucleotides in the 5 prime to 3 prime direction. The complementary bases are Adenine/Thymine and Guanine/Cytosine. Nucleotides are added going towards the replication fork (point where the helicase is splitting the nucleotides).

3’

5’

Leading Strand

T

T

T

A

A

G

C

C

C

A

DNA Polymerase

III

T

G

C

T

G

A

A

G

C

T

Nucleotide

Sugar

Phosphate

Adenine

Guanine

Cytosine

Thymine

Key

DNA Replication

DNA polymerase III reads the DNA strands from 3 prime to 5 prime and adds complementary nucleotides in the 5 prime to 3 prime direction. The complementary bases are Adenine/Thymine and Guanine/Cytosine. Nucleotides are added going towards the replication fork (point where the helicase is splitting the nucleotides).

3’

5’

Leading Strand

T

T

T

A

A

G

C

C

C

A

DNA Polymerase

III

T

G

G

C

T

G

A

A

G

C

T

Nucleotide

Sugar

Phosphate

Adenine

Guanine

Cytosine

Thymine

Key

DNA Replication

DNA polymerase III reads the DNA strands from 3 prime to 5 prime and adds complementary nucleotides in the 5 prime to 3 prime direction. The complementary bases are Adenine/Thymine and Guanine/Cytosine. Nucleotides are added going towards the replication fork (point where the helicase is splitting the nucleotides).

3’

5’

Leading Strand

T

T

T

A

A

G

C

C

C

A

T

G

A

A

G

C

T

Nucleotide

Sugar

Phosphate

Adenine

Guanine

Cytosine

Thymine

Key

DNA Replication

The leading strand is made continuously due to DNA polymerase III being able to add nucleotides to a 3 prime end. The leading strand starts with a 3 prime end making this process easy. Single stranded proteins are no longer needed to stabilize the DNA strand so they detach and move to a new location where they are needed.

3’

5’

Leading Strand

G

C

T

G

A T

T

T

A

A

G

C

C

C

A

T

G

A

A

G

C

T

Nucleotide

Sugar

Phosphate

Adenine

Guanine

Cytosine

Thymine

Key

DNA Replication

Of course, the lagging strand has to be difficult. The lagging strand is unparalleled to the leading strand meaning it starts with a 5 prime and ends with a 3 prime. It is made discontinuously due to DNA polymerase III not being able to add nucleotides to the 5 prime end. Nucleotides are added away from the replication fork with the help of many components.

3’

5’ Lagging Strand

G

A

A

A

T

T

G

G

C

Protein Stabilizer

A

G

C

T

Nucleotide

Sugar

Phosphate

Adenine

Guanine

Cytosine

Thymine

Key

DNA Replication

In order for new nucleotides to be added onto the lagging strand a RNA primer is added by DNA primase to create a 3 prime end. DNA polymerase III can then add nucleotides to the complementary strand.

3’

5’ Lagging Strand

G

A

A

A

T

T

G

G

C

Protein Stabilizer

A

G

C

T

Nucleotide

Sugar

Phosphate

Adenine

Guanine

Cytosine

Thymine

Key

DNA Replication

In order for new nucleotides to be added onto the lagging strand a RNA primer is added by DNA primase to create a 3 prime end. DNA polymerase III can then add nucleotides to the complementary strand.

3’

5’ Lagging Strand

G

A

A

A

T

T

G

G

C

Protein Stabilizer

DNA Primase

A

G

C

T

Nucleotide

Sugar

Phosphate

Adenine

Guanine

Cytosine

Thymine

Key

DNA Replication

In order for new nucleotides to be added onto the lagging strand a RNA primer is added by DNA primase to create a 3 prime end. DNA polymerase III can then add nucleotides to the complementary strand.

3’

5’ Lagging Strand

G

A

A

A

T

T

G

G

C

Protein Stabilizer

DNA Primase

RNA Primer

A

G

C

T

Nucleotide

Sugar

Phosphate

Adenine

Guanine

Cytosine

Thymine

Key

DNA Replication

In order for new nucleotides to be added onto the lagging strand a RNA primer is added by DNA primase to create a 3 prime end. DNA polymerase III can then add nucleotides to the complementary strand.

3’

5’ Lagging Strand

Protein Stabilizer

G

A

A

A

T

T

G

G

C

RNA Primer

3’

A

G

C

T

Nucleotide

Sugar

Phosphate

Adenine

Guanine

Cytosine

Thymine

Key

DNA Replication

In order for new nucleotides to be added onto the lagging strand a RNA primer is added by DNA primase to create a 3 prime end. DNA polymerase III can then add nucleotides to the complementary strand.

3’

5’ Lagging Strand

Protein Stabilizer

G

A

A

A

T

T

G

G

C

RNA Primer

DNA Po

lymer

ase

III3’

3’

A

G

C

T

Nucleotide

Sugar

Phosphate

Adenine

Guanine

Cytosine

Thymine

Key

DNA Replication

In order for new nucleotides to be added onto the lagging strand a RNA primer is added by DNA primase to create a 3 prime end. DNA polymerase III can then add nucleotides to the complementary strand.

3’

5’ Lagging Strand

Protein Stabilizer

G

A

A

A

T

T

G

G

C

RNA Primer

DNA Po

lymer

ase

III

3’

A

G

C

T

Nucleotide

Sugar

Phosphate

Adenine

Guanine

Cytosine

Thymine

Key

DNA Replication

In order for new nucleotides to be added onto the lagging strand a RNA primer is added by DNA primase to create a 3 prime end. DNA polymerase III can then add nucleotides to the complementary strand.

3’

5’ Lagging Strand

Protein Stabilizer

G

A

A

A

T

T

G

G

C

DNA Po

lymer

ase

III

A

3’

A

G

C

T

Nucleotide

Sugar

Phosphate

Adenine

Guanine

Cytosine

Thymine

Key

DNA Replication

In order for new nucleotides to be added onto the lagging strand a RNA primer is added by DNA primase to create a 3 prime end. DNA polymerase III can then add nucleotides to the complementary strand.

3’

5’ Lagging Strand

Protein Stabilizer

G

A

A

A

T

T

G

G

C

DNA Po

lymer

ase

III

A

3’

A

G

C

T

Nucleotide

Sugar

Phosphate

Adenine

Guanine

Cytosine

Thymine

Key

DNA Replication

In order for new nucleotides to be added onto the lagging strand a RNA primer is added by DNA primase to create a 3 prime end. DNA polymerase III can then add nucleotides to the complementary strand.

3’

5’ Lagging Strand

Protein Stabilizer

G

A

A

A

T

T

G

G

C

CDNA

Polym

eras

e III

T

A

3’

A

G

C

T

Nucleotide

Sugar

Phosphate

Adenine

Guanine

Cytosine

Thymine

Key

DNA Replication

In order for new nucleotides to be added onto the lagging strand a RNA primer is added by DNA primase to create a 3 prime end. DNA polymerase III can then add nucleotides to the complementary strand.

3’

5’ Lagging Strand

Protein Stabilizer

G

A

A

A

T

T

G

G

C

CDNA

Polym

eras

e III

T

A

3’

A

G

C

T

Nucleotide

Sugar

Phosphate

Adenine

Guanine

Cytosine

Thymine

Key

DNA Replication

In order for new nucleotides to be added onto the lagging strand a RNA primer is added by DNA primase to create a 3 prime end. DNA polymerase III can then add nucleotides to the complementary strand.

3’

5’ Lagging Strand

Protein Stabilizer

G

A

A

A

T

T

G

G

C

C

T

T

A

3’

A

G

C

T

Nucleotide

Sugar

Phosphate

Adenine

Guanine

Cytosine

Thymine

Key

DNA Replication

As DNA helicase keeps splitting the strands, more and more RNA primers are added by DNA primase. DNA polymerase III jumps to the next RNA primer and adds nucleotides going back to the previous RNA primer.

3’

5’ Lagging Strand

Protein Stabilizer

G

A

A

A

T

T

G

G

C

C

T

T

A

3’

A

G

C

T

Nucleotide

Sugar

Phosphate

Adenine

Guanine

Cytosine

Thymine

Key

DNA Replication

As DNA helicase keeps splitting the strands, more and more RNA primers are added by DNA primase. DNA polymerase III jumps to the next RNA primer and adds nucleotides going back to the previous RNA primer.

3’

5’ Lagging Strand

Protein Stabilizer

G

A

A

A

T

T

G

G

C

C

T

Previous RNA Primer

Next RNA Primer

5’

3’

T

A

3’

A

G

C

T

Nucleotide

Sugar

Phosphate

Adenine

Guanine

Cytosine

Thymine

Key

DNA Replication

As DNA helicase keeps splitting the strands, more and more RNA primers are added by DNA primase. DNA polymerase III jumps to the next RNA primer and adds nucleotides going back to the previous RNA primer.

3’

5’ Lagging Strand

Protein Stabilizer

G

A

A

A

T

T

G

G

C

C

T

Previous RNA Primer

Next RNA Primer

5’

3’DNA

Polymerase

III

T

A

3’

A

G

C

T

Nucleotide

Sugar

Phosphate

Adenine

Guanine

Cytosine

Thymine

Key

DNA Replication

As DNA helicase keeps splitting the strands, more and more RNA primers are added by DNA primase. DNA polymerase III jumps to the next RNA primer and adds nucleotides going back to the previous RNA primer.

3’

5’ Lagging Strand

Protein Stabilizer

G

A

A

A

T

T

G

G

C

C

T

Previous RNA Primer

Next RNA Primer

5’

3’DNA

Polymerase

III

T

A

3’

A

G

C

T

Nucleotide

Sugar

Phosphate

Adenine

Guanine

Cytosine

Thymine

Key

DNA Replication

As DNA helicase keeps splitting the strands, more and more RNA primers are added by DNA primase. DNA polymerase III jumps to the next RNA primer and adds nucleotides going back to the previous RNA primer.

3’

5’ Lagging Strand

Protein Stabilizer

G

A

A

A

T

T

G

G

C

C

T

Previous RNA Primer

Next RNA Primer

5’

3’DNA

Polymerase

III

T

A

3’

A

G

C

T

Nucleotide

Sugar

Phosphate

Adenine

Guanine

Cytosine

Thymine

Key

DNA Replication

As DNA helicase keeps splitting the strands, more and more RNA primers are added by DNA primase. DNA polymerase III jumps to the next RNA primer and adds nucleotides going back to the previous RNA primer.

3’

5’ Lagging Strand

Protein Stabilizer

G

A

A

A

T

T

G

G

C

C

T

Previous RNA Primer

Next RNA Primer

5’

3’DNA

Polymerase

III

T

A

3’

A

G

C

T

Nucleotide

Sugar

Phosphate

Adenine

Guanine

Cytosine

Thymine

Key

DNA Replication

As DNA helicase keeps splitting the strands, more and more RNA primers are added by DNA primase. DNA polymerase III jumps to the next RNA primer and adds nucleotides going back to the previous RNA primer.

3’

5’ Lagging Strand

Protein Stabilizer

G

A

A

A

T

T

G

G

C

C

T

Previous RNA Primer

Next RNA Primer

5’

3’

DNA

Polym

eras

e III

T

A

3’

A

G

C

T

Nucleotide

Sugar

Phosphate

Adenine

Guanine

Cytosine

Thymine

Key

DNA Replication

As DNA helicase keeps splitting the strands, more and more RNA primers are added by DNA primase. DNA polymerase III jumps to the next RNA primer and adds nucleotides going back to the previous RNA primer.

3’

5’ Lagging Strand

Protein Stabilizer

G

A

A

A

T

T

G

G

C

C

T

Previous RNA Primer

Next RNA Primer

5’

3’C

DNA

Polym

eras

e III

T

A

3’

A

G

C

T

Nucleotide

Sugar

Phosphate

Adenine

Guanine

Cytosine

Thymine

Key

DNA Replication

As DNA helicase keeps splitting the strands, more and more RNA primers are added by DNA primase. DNA polymerase III jumps to the next RNA primer and adds nucleotides going back to the previous RNA primer.

3’

5’ Lagging Strand

Protein Stabilizer

G

A

A

A

T

T

G

G

C

C

T

Previous RNA Primer

Next RNA Primer

5’

3’C

DNA

Polym

eras

e III

A

T

A

3’

A

G

C

T

Nucleotide

Sugar

Phosphate

Adenine

Guanine

Cytosine

Thymine

Key

DNA Replication

As DNA helicase keeps splitting the strands, more and more RNA primers are added by DNA primase. DNA polymerase III jumps to the next RNA primer and adds nucleotides going back to the previous RNA primer.

3’

5’ Lagging Strand

Protein Stabilizer

G

A

A

A

T

T

G

G

C

C

T

Previous RNA Primer

Next RNA Primer

5’

3’C

ADNA

Polymerase

III

T

A

3’

A

G

C

T

Nucleotide

Sugar

Phosphate

Adenine

Guanine

Cytosine

Thymine

Key

DNA Replication

As DNA helicase keeps splitting the strands, more and more RNA primers are added by DNA primase. DNA polymerase III jumps to the next RNA primer and adds nucleotides going back to the previous RNA primer.

3’

5’ Lagging Strand

Protein Stabilizer

G

A

A

A

T

T

G

G

C

C

T

Previous RNA Primer

Next RNA Primer

5’

3’C

ADNA

Polymerase

III

T

A

3’

A

G

C

T

Nucleotide

Sugar

Phosphate

Adenine

Guanine

Cytosine

Thymine

Key

DNA Replication

These new fragments are called Okazaki fragments after the scientist that founded them.

3’

5’ Lagging Strand

Protein Stabilizer

G

A

A

A

T

T

G

G

C

C

T

5’

3’C

A

Okazaki Fragments

T

A

A

G

C

T

Nucleotide

Sugar

Phosphate

Adenine

Guanine

Cytosine

Thymine

Key

DNA Replication

DNA polymerase I comes into the replication process by changing the RNA into DNA.

3’

5’ Lagging Strand

Protein Stabilizer

G

A

A

A

T

T

G

G

C

C

T

C

A

T

A

A

G

C

T

Nucleotide

Sugar

Phosphate

Adenine

Guanine

Cytosine

Thymine

Key

DNA Replication

DNA polymerase I comes into the replication process by changing the RNA into DNA.

3’

5’ Lagging Strand

Protein Stabilizer

G

A

A

A

T

T

G

G

C

C

T

C

A

DNA Polymerase

I

T

A

A

G

C

T

Nucleotide

Sugar

Phosphate

Adenine

Guanine

Cytosine

Thymine

Key

DNA Replication

DNA polymerase I comes into the replication process by changing the RNA into DNA.

3’

5’ Lagging Strand

Protein Stabilizer

G

A

A

A

T

T

G

G

C

C

T

C

A

DNA Polymerase

I

T

A

A

G

C

T

Nucleotide

Sugar

Phosphate

Adenine

Guanine

Cytosine

Thymine

Key

DNA Replication

DNA polymerase I comes into the replication process by changing the RNA into DNA.

3’

5’ Lagging Strand

Protein Stabilizer

G

A

A

A

T

T

G

G

C

C

T

C

A

DNA Polymerase

I

T

A

A

G

C

T

Nucleotide

Sugar

Phosphate

Adenine

Guanine

Cytosine

Thymine

Key

DNA Replication

DNA polymerase I comes into the replication process by changing the RNA into DNA.

3’

5’ Lagging Strand

Protein Stabilizer

G

A

A

A

T

T

G

G

C

C

T

C

A

DNA Polymerase

I

G

T

A

A

G

C

T

Nucleotide

Sugar

Phosphate

Adenine

Guanine

Cytosine

Thymine

Key

DNA Replication

DNA polymerase I comes into the replication process by changing the RNA into DNA.

3’

5’ Lagging Strand

Protein Stabilizer

G

A

A

A

T

T

G

G

C

C

T

C

A DNA Polymerase

I

G

C

T

A

A

G

C

T

Nucleotide

Sugar

Phosphate

Adenine

Guanine

Cytosine

Thymine

Key

DNA Replication

DNA polymerase I comes into the replication process by changing the RNA into DNA.

3’

5’ Lagging Strand

Protein Stabilizer

G

A

A

A

T

T

G

G

C

C

T

C

A

DNA Polymerase

I

G

C

T

A

A

G

C

T

Nucleotide

Sugar

Phosphate

Adenine

Guanine

Cytosine

Thymine

Key

DNA Replication

DNA polymerase I comes into the replication process by changing the RNA into DNA.

3’

5’ Lagging Strand

Protein Stabilizer

G

A

A

A

T

T

G

G

C

C

T

C

A

G

C

T

T

A

A

G

C

T

Nucleotide

Sugar

Phosphate

Adenine

Guanine

Cytosine

Thymine

Key

DNA Replication

DNA ligase then forms phosphodiester bonds between the Okazaki fragments and DNA added by polymerase I.

3’

5’ Lagging Strand

Protein Stabilizer

G

A

A

A

T

T

G

G

C

C

T

C

A

G

C

T

T

A

A

G

C

T

Nucleotide

Sugar

Phosphate

Adenine

Guanine

Cytosine

Thymine

Key

DNA Replication

DNA ligase then forms phosphodiester bonds between the Okazaki fragments and DNA added by polymerase I.

3’

5’ Lagging Strand

Protein Stabilizer

G

A

A

A

T

T

G

G

C

C

T

C

A

G

C

T

Ligase

Okazaki Fragments

New DNA

T

A

A

G

C

T

Nucleotide

Sugar

Phosphate

Adenine

Guanine

Cytosine

Thymine

Key

DNA Replication

DNA ligase then forms phosphodiester bonds between the Okazaki fragments and DNA added by polymerase I.

3’

5’ Lagging Strand

Protein Stabilizer

G

A

A

A

T

T

G

G

C

C

T

C

A

G

C

T

Ligase

Okazaki Fragments

New DNA

T

A

A

G

C

T

Nucleotide

Sugar

Phosphate

Adenine

Guanine

Cytosine

Thymine

Key

DNA Replication

DNA ligase then forms phosphodiester bonds between the Okazaki fragments and DNA added by polymerase I.

3’

5’ Lagging Strand

Protein Stabilizer

G

A

A

A

T

T

G

G

C

C

T

C

A

G

C

T

Ligase

Okazaki Fragments

New DNA

T

A

A

G

C

T

Nucleotide

Sugar

Phosphate

Adenine

Guanine

Cytosine

Thymine

Key

DNA Replication

DNA ligase then forms phosphodiester bonds between the Okazaki fragments and DNA added by polymerase I.

3’

5’ Lagging Strand

Protein Stabilizer

G

A

A

A

T

T

G

G

C

C

T

C

A

G

C

T

Ligase

Okazaki Fragments

New DNA

T

A

A

G

C

T

Nucleotide

Sugar

Phosphate

Adenine

Guanine

Cytosine

Thymine

Key

DNA Replication

DNA ligase then forms phosphodiester bonds between the Okazaki fragments and DNA added by polymerase I.

3’

5’ Lagging Strand

Protein Stabilizer

G

A

A

A

T

T

G

G

C

C

T

C

A

G

C

T

Ligase

Okazaki Fragments

New DNA

T

A

A

G

C

T

Nucleotide

Sugar

Phosphate

Adenine

Guanine

Cytosine

Thymine

Key

DNA Replication

The single stranded proteins are no longer needed to stabilize this part of the DNA strand so they detach and move on to the next part of the strand that needs stabilized.

3’

5’ Lagging Strand

Protein Stabilizer

G

A

A

A

T

T

G

G

C

C

T

C

A

G

C

T

T

A

A

G

C

T

Nucleotide

Sugar

Phosphate

Adenine

Guanine

Cytosine

Thymine

Key

DNA Replication

The single stranded proteins are no longer needed to stabilize this part of the DNA strand so they detach and move on to the next part of the strand that needs stabilized.

3’

5’ Lagging Strand

G

A

A

A

T

T

G

G

C

C

T

C

A

G

C

T

A

G

C

T

Nucleotide

Sugar

Phosphate

Adenine

Guanine

Cytosine

Thymine

Key

DNA Replication

There are now two identical strands of DNA and each will twist into a double helix.

Lagging Strand

T

A

G

A

A

A

T

T

G

G

C

C

T

C

A

G

C

T

G

C

T

G

A T

T

T

A

A

G

C

C

C

A

T

G

A

Leading Strand

• DNA replication needs to happen for new cells to divide. The cells need a copy of the DNA or instructions to function and know what to do.

• Mutations can occur when there is an error in the DNA sequence (adenine, thymine, guanine, and cytosine). Errors in the sequence are things such as a missing sequence piece, the bases are paired up wrong, or duplication (a piece of DNA is copied one or more times).

• Mutations can lead to diseases, cancer, color blindness, sickle cell, and many more. Some mutations are inherited from the parent organisms, some mutations happen due to environmental factors, and of course some happen due to cell division.

• Not all mutations are bad. Mutations can happen to make an organisms healthier over time by creating genetic diversity.

More Information

More Information

• Telomeres: when talking about chromosomes the telomeres are the long parts of the chromosome pinched in the middle by what is called the centromere. Telomeres keep other chromosomes in the cell from becoming attached to one another.

• Okazaki Fragments: a section of the lagging complementary strand that synthesizes off of the RNA primer and is later bonded together by DNA ligase

• DNA Ligase: “stiches” the Okazaki fragments together by forming phospodiester bonds

• Telomerase: an enzyme that makes DNA from a RNA template. Telomerase is generally found in stem cells and unicellular eukaryotes

• Cancer: cancer cells can grow indefinitely and contain telomerase. Cancer is a type of bad mutated cell that harms organisms.

More Information

• Transplanted Cells: removing cells from an organism, changing the cells with the gene that the organisms was unable to make, and returning the improved cell back to the organism

• Cloning: creating the same organism from the nucleus of a cell from an adult organism

• Aging: progressive loss of mental functions that increase the chance of death. Aging of course starts in the cells. When cells are not produced as efficiently or do not work as smoothly it is generally due to aging but, it could also be cause of mutations, disease, and environmental factors.

THE END!