PCR and protien synthesis Flashcards
what does PCR stand for
Polymerase Chain Reaction
what enzyme is used in PCR and what is special about it
Taq DNA polymerase, heat tolerant
what temperature is the DNA heated to in PCR and why
94 to denature it
what happens in the second stage of PCR
cooled to 55 to allow primers to anneal
what temperature is the DNA heated to the second time
72
what are the uses of PCR
catching criminals, diagnosing genetic disorders and paternity suits
how is RNA different to DNA
single stranded, uracil base instead of thymine, ribose sugar instead of deoxyribose
what does mRNA do
caries genetic information from the nucleus to the cytoplasm for protein synthesis
what does tRNA do
carries amino acids on the anti-codon to the codon to form a polypeptide
what happens in transcription
RNA polymerase unwinds and breaks DNA, it then adds free RNA nucleotides to the DNA bases, when the transcription is complete, the RNA polymerase is released and a primary transcript is produced. this happens in the nucleus
why is the Primary transcript shorter than the original DNA strand
it only codes for one protein
what happens during splicing
the non coding introns are removed leaving the mature transcript made up of exons, this happens in the nucleus and this mRNA then leaves the nucleus via a nuclear pore and enters the cytoplasm
what happens in translation
as the mRNA passes through the ribosome, it binds to it so that the start codon is in position. the appropriate, complementary tRNA anti-codon then brings an amino acid to the ribosome and moves it along the mRNA. adjacent amino acids then join together and the tRNA is released. this process continues until a stop codon is reached and a polypeptide chain is released
what is alternative RNA splicing
exons can be targeted for removal or kept which creates an array of different mRNAs from the primary transcript. this means one gene can create many proteins
what is post translation modification
the polypeptide chain folds and is held together by hydrogen bonds creating a 3D protein. a proteins shape determines its function
