Semi-conservative Replication Flashcards
What is the FIRST stage of semi-conservative replication in DNA?
- DNA helicase (an enzyme) breaks the hydrogen bonds between the two polynucleotide strands and untwists the DNA. It forms two single strands.
What is the SECOND stage of semi-conservative replication in DNA?
- Each original single strand acts as a template for a new strand. Free phosphorylated nucleotides join to the exposed bases on each original template strand by complementary base pairing.
What is the THIRD stage of semi-conservative replication in DNA?
- An enzyme called DNA polymerase links the sugar phosphate backbone by phosphodiester bonds. Hydrogen bonds form between the bases on the original and new strand. The strands twist to form a double helix.
What is the FOURTH stage of semi-conservative replication in DNA?
- Each new DNA molecule contains one strand from the original DNA molecule and one new strand.
Why is this called semi-conservative replication?
Because half of the strands in each new DNA molecule are from the original piece of DNA (that is the new molecule contains one old strand and one new strand).
Is DNA replication accurate?
It’s accurate - it must be to make sure genetic information is conserved (stays the same) each time the DNA in a cell is replicated.
What is a mutation and how can it impact DNA?
A mutation is any change to the DNA base sequence. Mutations don’t always have an effect, but they can alter the sequence of amino acids in a protein. This can cause an abnormal protein to be produced. The abnormal protein might function better than the normal protein - or it might not work at all.
