AP Biology

DNA Structure & Replication

Nucleic Acid Structure

Complimentary Base Pairing

S Phase of Cell Cycle

ThetaReplication

in Prokaryotes

Origin ofreplication

Replication fork

Termination of replication

Linear Replication in Eukaryotes

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The parent molecule has two complementary strands of DNA. Each base is paired by hydrogen bonding with its specific partner, A with T and G with C.

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The parent molecule has two complementary strands of DNA. Each base is paired by hydrogen bonding with its specific partner, A with T and G with C.

The first step in replication is separation of the two DNA strands.

Semi Conservative process of DNA Replication

The parent molecule has two complementary strands of DNA. Each base is paired by hydrogen bonding with its specific partner, A with T and G with C.

The first step in replication is separation of the two DNA strands.

Each parental strand now serves as a template that determines the order of nucleotides along a new, complementary strand.

Origins and Replication bubbles

DNA Replication

DNA Replication by adding Nucleosides on the 3’ end

New strand

5 end

Phosphate Base

Sugar

Template strand

3 end 5 end 3 end

5 end

3 end

5 end

3 end

Nucleosidetriphosphate

DNA polymerase

Pyrophosphate

5 Carbon Sugar Important Parts(It could be DNA or RNA)

Helicase is the GREEN “blob”

RNA Primer(Remember, RNA is temporary)

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New strand

5 end

Phosphate Base

Sugar

Template strand

3 end 5 end 3 end

5 end

3 end

5 end

3 end

Nucleosidetriphosphate

DNA polymerase

Pyrophosphate

Nucleotide Excision Repair

Telomere Removal at the

Chromosome Ends

End of parentalDNA strands

5

3

Lagging strand 5

3

Last fragment

RNA primer

Leading strandLagging strand

Previous fragment

Primer removed butcannot be replacedwith DNA becauseno 3 end available

for DNA polymerase5

3

Removal of primers andreplacement with DNAwhere a 3 end is available

Second roundof replication

5

3

5

3Further roundsof replication

New leading strand

New leading strand

Shorter and shorterdaughter molecules

Apoptosis in the hand