3.9 DNA Replication and the Genetic Code Flashcards
What is DNA replication?
the process of making a copy of the genetic information in DNA
why is DNA replication important?
cell division and the transfer of genetic information from one generation to the next
when does DNA replication occur?
interphase
where does DNA replication occur?
the nucleus
what enzymes are involved in DNA replication?
DNA helicase and DNA polymerase
what does DNA helicase do?
unzips the double helix by disrupting the hydrogen bonds between the anti-parallel strands
what does DNA polymerase do?
creates complementary strands of DNA during replication, it adds nucleotides to form a polynucleotide
what is semi-conservative replication
the new DNA has one new strand and one orignal strand. the original strand acts as a template for the new strand. both DNA molecules formed are identical
what are the steps of DNA replication
- DNA helicase unzips the DNA by breaking hydrogen bonds, forming 2 single strands
- free nucleotides are attched to their complementary bases and the hydrogen bonds reform between them
- once the new nucleotides have lined up, DNA polymerase attaches them and new phosphodiester bonds form between them
- all nucleotides along the whole length are joined forming two complete identical chains, each retaining half the original DNA
what is a mutation?
sequences of bases arent always matched exactly and an incorrect sequence may occur in the newly-copied strand. these error occur randomly and spontaneously and can lead to a change in the sequence of bases
what is a codon?
sequences of 3 bases that code for an amino acid
what is a gene
the complete sequence of bases to code for an entire protein
what is a degenerate code
multiple codons encode a single amino acid
