transcription and translation Flashcards
(35 cards)
genome
complete set of genes in a cell
proteome
set of proteins that a gene codes for.
What occurs during transcription?
The DNA code of a gene is converted to a string of code on an mRNA molecule in the nucleus.
What occurs during translation?
Once the strand of mRNA travels to the cytoplasm, the code is translated into a sequence of amino acids forming a polypeptide.
what is made during transcription?
mRNA
where does transcription take place in eukaryotic cells?
the nucleus
where does translation take place?
the cytoplasm.
There are 6 steps in transcription. What is the first step?
The hydrogen bonds between the 2 DNA strands break.
what is the second step in transcription?
One of the strands of the DNA acts as a template.
What is the third step in transcription?
Free RNA nucleotides line up to the exposed bases on the template strand by complementary base pairing.
What is the fourth step in transcription?
On the RNA strand, base T is replaced by U, and so base A on the template strand is paired with base U on the single mRNA strand.
What is the fifth step in transcription?
Adjacent RNA nucleotides are joined together by RNA polymerase by phosphodiester bonds.
What is the sixth step in transcription?
Finally introns are removed/spliced from pre-mRNA to form mRNA.
introns
non-coding protein
what happens to introns?
they are spliced out of pre-mRNA to produce the final mRNA strand.
where does transcription take place in prokaryotic cells?
Transcription takes place in the cytoplasm.
does prokaryotic DNA contain intorns?
no - so splicing is not necessary.
When rRNA reaches a … it stops making … and detaches from the DNA.
When rRNA reaches a stop codon it stops making mRNA and detaches from the DNA.
Once RNA polymerase detaches from the DNA, mRNA…
… moves out of the nucleus through a nuclear pore and attaches to a ribosome in the protein.
where does translation take place?
at the ribosomes of the cytoplasm.
each tRNA molecule has an …
amino acid binding site at one end and an anti-codon at the other end.
what is an anti-codon?
3 bases at one end of a tRNA molecule.
what bonds are formed during translation?
peptide bonds form between amino acids. This makes a polypeptide chain which goes on to form a protein.
how are amino acids joined together in translation?
they are joined together using the sequence of codons carried by the mRNA.
