DNA Replication Flashcards
What is the role of DNA polymerase?
DNA polymerase catalyses the formation of a new polynucleotide chain
What is the role of DNA ligase?
DNA ligase joins together the short sections of the lagging strand
What is the role of Helicase in DNA replication?
Helicase separates the two DNA strands
What is the role of the single-stranded binding protein in DNA replication?
The single-stranded binding protein keeps the separated DNA strands apart during replication
How does DNA replicate?
DNA replicates semi-conservatively
True or false? The strands in a DNA molecule are parallel to one another.
False: the strands run Anti-parallel to each other
What is the name of the point where the two strands of DNA are separated?
The replication fork
What direction does the leading strand run?
5’ to 3’
The leading strand is replicated continuously
What direction does the lagging strand run?
3’ to 5’
The lagging strand is replicated discontinuously from 5’ to 3’
What is a phosphodiester bond?
It is the covalent bond that forms between the pentose sugar and the phosphate of different nucleotides
What is the role of DNA?
It codes for the sequence of amino acids in the primary structure of a protein
What type of protein is DNA?
It is a fibrous protein and has a stable structure due to its sugar phosphate backbone
What is advantageous about DNA consisting of complementary base pairing?
It allows identical copies to be made easily
What are the three types of RNA?
rRNA = ribosomal RNA
tRNA = transfer RNA
mRNA = messenger RNA
What is mRNA?
It is a copy of a gene from DNA
It is able to leave the nucleus carrying the genetic code of a gene to a ribosome.
What is the role of tRNA?
It brings a specific amino acid to the ribosome. As the amino acid binds to the top of it.
Why is DNA replication described as semi-conservative?
It is described as semi-conservative as one strand is conserved and one strand is created
How may a mutation occur?
When a copying error in DNA replication occurs randomly
What are the two stages of protein synthesis?
Transcription - where the DNA sequence for one gene is copied into mRNA
Translation - where the mRNA joins with a ribosome and a corresponding tRNA molecule brings the specific amino acid the codon codes for
What are stop and start codons?
At the start of every gene there is a start codon which enables the ribosome to attach. At the end of every gene there are 3 bases which don’t code for an amino acid causing the ribosome to detach and end translation.
