the central dogma of life( translation and transcription) Flashcards
name the stages of transcription in eukaryotes
Initiation
Elongation
Termination
transcription of DNA
a fundamental biological process that involves the synthesis of a complementary RNA (ribonucleic acid) strand from a DNA (deoxyribonucleic acid) template
what happens during the initiation stage of transcription
transcription factors bind to the promoter region upstream of the gene which needs to be transcribed.
function of the promoter region
its primary function is to regulate the initiation of transcription, the process by which genetic information encoded in DNA is transcribed into RNA.
transcription factors function
they trigger the binding of RNA polymerase to DNA, to initiate transcription
briefly describe the elongation stage of transcription
The elongation stage of transcription is the phase during which RNA polymerase, the enzyme responsible for transcription, moves along the DNA template strand, synthesizing an RNA molecule.
in what direction does the RNA polymerase “walk” along the DNA template strand
from the 3’ to the 5’ direction
briefly describe the termination stage of transcription
refers to the process of stopping transcription, and it happens once the polymerase transcribes a sequence of DNA known as the terminator
the polyadenylation signal
AAUAAA
polyadenylation(poly-A tail addition)
post-transcriptional modification that occurs during the processing of pre-messenger RNA (pre-mRNA) in eukaryotic cells.
what is the purpose of polyadenylation?
it signals the termination of transcription
splicing
a crucial post-transcriptional process in eukaryotic cells that involves the removal of non-coding sequences (introns) from the pre-mRNA and the joining together of coding sequences (exons) to produce a mature and functional mRNA molecule
what happens when there are errors during splicing
can lead to the production of aberrant or non-functional proteins
they are associated with various genetic disorders and diseases.
differences between genes in prokaryotes and eukaryotes
For prokaryotes;
DNA is in the cytoplasm
it has a circular chromosome
DNA not wound around histone proteins
it has no introns
For eukaryotes;
DNA in nucleus
linear chromosomes
DNA wound on histone proteins
has introns and exons
DNA translation
the process by which the information encoded in the sequence of nucleotides in DNA is used to synthesize a protein
codons
blocks of 3 nucleotides coded into the sequence of amino acids
During transcription, what name is given to the strand that RNA polymerase binds to
what about the strand that is not read
the template strand/ anti-sense strand
the coding strand
what does it mean when we say the DNA code is redundant?
it means that several codons can code for one amino acid
tRNA is aka
Transfer RNA
structure of TRNA
it has a clover leaf structure
when on tRNA can the anticodon be found
on the clover leaf end
when on tRNA do amino acids attach
on the 3’ end
the function of ribosomes during translation
Facilitate coupling of tRNA anticodon to mRNA codon
how many subunits of ribosomes are there
name them
2
large and small
how many sites do ribosomes have for binding to tRNA
name these sites
3
the peptidyl or donor site (P)
the aminoacyl or acceptor site (A)
the exit site (E)
function of the A site of ribosomes
holds tRNA carrying the next amino acid to be added to the chain
function of the P site of ribosomes
holds tRNA carrying growing polypeptide chain
function of the E site of ribosomes
empty tRNA leaves ribosome from exit site
the TATA box
a recognition site for transcription factors, typically upstream the gene to be transcribed
in what direction is mRNA synthesised in transcription
5’ end to 3’ end
Purpose of polyadenylation
Makes the rna molecule more stable and prevents its degradation
