DNA Replication, Transcription and Translation Flashcards
Define genome
the total gentic code
the total set of nitrogenous bases in all of the chromosomes
What is the 1st step of DNA Replication?
the double helix unwinds
this is driven by the enxyme topoisomerase
What is the 2nd step of DNA Replication?
the enzyme helicase where to start unzipping double helix
now there are exposed bases
What is the 3rd step of DNA Replication?
the enzyme primase directs the enzyme DNA Polymerase where to begin matching nucleotides to their complementary base pairs in the DNA and is the builder
* Now there are 2 strands of DNA each with one side of original DNA and 1 side of brand new DNA
the free nucleotides were floating around the cell.
What is the 4th step of DNA Replication?
the enzyme ligase sticks the free nucleotides to their matching base pairs (acts as glue) and attaches the newly linked strand together.
What processes help polypeptide synthesis occur?
Through transcription and translation
Where does transcription occur?
Inside the nucleus
Why does transcription occur?
the DNA is too large to leave the nucleus and reach the ribosome for polypeptide synthesis
What occurs in transcription?
a copy of one gene is made (called mRNA) and is able to leave nucleus to go to ribosome
mRNA = single-stranded and shorter than DNA, so it can leave the nucleus
What differs RNA to DNA?
RNA:
* single-stranded
* shorter
* uses Uracil instead of Thymine (U replaces T)
* 3 types: mRNA, tRNA, rRNA
DNA:
* double-stranded
* longer
Where does translation occur?
inside the ribosome
Why does transcription occur?
to create a polypeptide chain, and synthesis proteins/polypeptides
What occurs in translation?
the mRNA has a sequence of triplet codons, and the tRNA attachs the specific anticodon that they carry. The amino acids attached to the tRNA connect to the mRNA and the tRNA dettaches, leaving a polypeptide chain behind
tRNA: triplet codon; connected to tRNA; translates them into amino acid
amino acids connect together to make polypeptide chains
