TOPIC 4 - protein synthesis Flashcards
what is the genome?
the complete set of genetic information contained in the cells of an organism.
what is the proteome?
the complete set of proteins that can be produced by a cell
describe the structure of mRNA?
A long single strand.
Base sequence is complementary to the DNA it was transcribed from
suggest the advantages of using mRNA than DNA for translation?
shorter + contains uracil = breaks down quickly so no excess polypeptides form
single stranded + linear = ribosome moves along strand and tRNA binds to exposed bases.
contains no introns.
describe the structure of tRNA?
-A single strand around 80 nucleotides.
- Folded into a clover leaf shape
-on one end is anti-codon
- on opposite end is amino acid binding site
what is produced by transcription?
mRNA
where does transcription takes place?
in the nucleus
outline the process of transcription?
- hydrogen bonds between DNA bases break
- DNA uncoils into 2 strands with exposed bases
- One strand is used as a template
- Free nucleotides line up next to complementary bases
- RNA polymerase catalyses the phosphodiester bonds between the asdjacent RNA nucleotides.
- complementary mRNA strand is formed
what happens to the pre-mRNA after transcription?
in eukaryotic cells, pre-mRNA must be spliced to remove introns, leaving only the coding regions.Then it moves out of the nucleus and attaches to a ribosome in the cytoplasm.
what is produced by translation?
proteins
where does translation take place?
In the cytoplasm (or ribosomes)
outline the process of translation?
- mRNA attaches to the ribosome
- tRNA collects amino acids from the cytoplasm
- the anti-codon of tRNA attaches to the complementary bases on the mRNA. two tRNA molecules attach to mRNA at a time
-amino acids bonded to the tRNA form peptide bonds, continuing to form a polypeptide chain until a stop codon is reached.
-this process requires ATP
