Chapter 3 — The Cell — Protein Synthesis Flashcards
one gene codes for one specific _______
protein
function of DNA in protein synthesis
codes for specific types of proteins
the goal of protein synthesis
to produce a specific polypeptide protein
2 main processes of protein synthesis (in sequential order)
transcription & translation
definition of transcription
to produce an mRNA copy of a gene that codes for a specific polypeptide protein
definition of translation
formation of a polypeptide protein from the mRNA template
2 main parts of transcription
exposure of the gene
copying of the gene
Where does transcription take place?
in the nucleus
before a gene can be transcribed, it must be ______
exposed
the two strands of DNA in a double helix are bound by
hydrogen bonds
enzyme that breaks the hydrogen bonds between DNA strands, exposing a gene for transcription
helicase
4 nitrogenous bases in DNA
adenine, thymine, cytosine, guanine
DNA nitrogenous base pairing
A+T, G+C
during transcription, Thymine is replaced by _______
Uracil
RNA nitrogenous base pairing
A+U, G+C
RNA is ______-stranded
single
What is a promoter site?
marker at the beginning of a gene that ‘tells’ the polymerase where to begin transcribing
What is RNApolymerase?
molecule that attaches to the gene and transcribes its bases into mRNA
What are trancription factors?
molecules that allow the polymerase to attach to the promoter site of a gene
What does the DNA do when the mRNA strand is complete?
resumes its normal (non-exposed) chromosome form
function of the mRNA strand
it is a template for the formation of a specific polypeptide protein
What is a codon?
a series of 3 base pairs on an mRNA strand which codes for a specific amino acid
the codons on an mRNA strand must be read in proper ______
sequence
definition of a polypeptide protein
a sequence of amino acids bound together in a specific order