8.3 dna replication

Dna replication

Process by which dna is copied during cell cycle

Where does dna replication take place in eukaryotic cell

Nuelcues

Why does dna replication need to occur

It ensures that every cell has a complete set of identical genetic information

What is a template

When the base sequence of one strand of the dna double helix is known

Used to make the new strands

What roles do proteins play in dna replicaiton

Hold strands apart while the strands serve as templates

What must be broken for the dna strand to separate

Hydrogen bonds

Why is dna replication called semiconservative

One original strand is conserved, and one complementary new strand is made

First step of replication and draw

Enzymes unzip the double helix at origins of replication

Hydrogen bonds connecting base pairs are broken, original molecule separates, and bases on each strand are exposed

Proceeds in two directions at a time

Second step of replication and draw

Free-floating nucleotides pari up with the exposed bases on each template strand as they are exposed

Dna polymerases bond the nucleotides together to form new strands complementary to each template strand

Final step of replication and draw

Two identical double stranded dna molecules result from replicaiton

Each new molecule has one strand from the original molecule and one new strand, therefore being semiconservative

End result of dna replication

Two identical molecules of dna result

Two major functions that dna polymerase performs

Bond the nucleotides together to form new strands complementary to the original strands

Proof reads and detects incorrectly paired nucleotides, replacing them with the correct nucleotides

What do human chromosomes have

Hundreds of origins of replication where dna is unzipped so replication can begin

What do dna polymerases have

Proofreading function that enables it to detect errors and correct them

Diagram of dna during replication