Transcription Flashcards
(13 cards)
Does DNA become RNA?
No, DNA is copied to produce a mRNA.
Where does transcription take place?
Nucleus
What is needed for transcription to take place?
DNA (gene), RNA polymerase enzyme, and RNA nucleotides (A, U, G, C).
What is a transcription bubble?
A small region of unwound DNA that forms when RNAP separates the two DNA strands, forming an ‘opened helix’.
What is the sequence of the mRNA product?
The sequence of the mRNA product is an exact match of the sequence in the coding strand.
What are the two strands in DNA?
The coding strand (sense) and the template strand (anti-sense).
What is the difference between pre-mRNA and mature mRNA?
Pre-mRNA contains both coding (exons) and non-coding (introns) sequences (raw version), while mature mRNA is the processed version where introns have been removed through splicing.
What is splicing?
Splicing is the process in which exons are recognised and are brought together to cut out introns.
What happens to the mature mRNA?
The mature mRNA then binds to ribosomes on the rough ER (in cytoplasm) for translation into proteins.
What is the key difference between DNA replication and transcription?
DNA replication creates an exact copy of an entire DNA molecule, while transcription produces a single RNA strand from a specific region of DNA.
Describe the process that converts pre-mRNA to RNA.
A spliceosome binds to several short nucleotide sequences along an intron. The intron is then released and rapidly degraded, and the spliceosome joins together the two exons on either side of the intron.
What is transcription?
Transcription is the synthesis of an RNA molecule from a DNA molecule.
Identify and describe the 3 steps in transcription.
- Initiation: RNA polymerase binds to the promoter, unwinds the DNA strands and initiates transcription.
- Elongation: RNA polymerase moves, unwinds the DNA and elongates the mRNA molecule.
- Termination: RNA polymerase detaches from the DNA and the mRNA transcript is released.
