Gene Expression Flashcards
What is Gene expression? and how are all genes expressed?
Gene expression involves the transcription and translation of DNA sequences.
Only a fraction of the genes in a cell are expressed.
List the three types of RNA involved in transcription and translation?
- mRNA: which carries a copy of the DNA code from the nucleus to the ribosome
- tRNA: which are molecules found in the cytoplasm that become attached to specific amino acids, bringing them to the ribosomes where they are joined together
- rRNA: which forms a complex with protein molecules to make the ribosome.
Describe mRNA in relation to transcription and translation?
mRNA is transcribed from DNA in the nucleus and translated into proteins by ribosomes in the cytoplasm
What is a codon?
Each triplet of bases on the mRNA molecule is called a codon and codes for a specific amino acid.
Describe tRNA in relation to transcription and translation?
tRNA folds due to complementary base pairing. Each tRNA molecule carries its specific amino acid to the ribosome.
What is an anti-codon?
tRNA molecule has an anticodon (an exposed triplet of bases) at one end and an attachment site for a specific amino acid at the other end.
What does RNA polymerase do?
RNA polymerase moves along DNA unwinding the double helix and breaking the hydrogen bonds between the bases and
synthesises a primary transcript of mRNA from RNA nucleotides by complementary base pairing.
What is the process that removes introns from the primary transcript?
RNA spilcing
Who forms a mature mRNA transcript?
RNA splicing forms a mature mRNA transcript.
What is removed during RNA splicing?
The introns of the primary transcript are non-coding regions and are removed.
What joins together to form mature transcript?
The exons are coding regions and are joined together to form the mature transcript.
The order of the exons is unchanged during splicing.
