Gene Expression Flashcards
What processes are involved in this reaction and where in the cell do they take place? DNA > mRNA > protein
Transcription - copying the code (nucleus)
Translation- changing the language (cytoplasm)
What is required for transcription and translation?
- Enzyme
- Activated Substrate
- Template
What 3 substances are required for transcription?
- RNA polymerase
- NTPs
- DNA
What 3 substances are required for translation?
- Ribosome
- Amino acids
- mRNA
What are the 3 stages of transcription?
- Initiation
- Elongation
- Termination
What term describes different lengths of RNA?
Transcription units
What is promoter recognition in transcription initiation ?
- Specific base sequence is recognised
- Transcription Initiation factor binds
- RNA polymerase surrounds transcription factor
What is meant by upstream and downstream transcription?
Upstream - transcription against the direction of the gene
Downstream - transcription with the direction of the gene
What influences gene expression in transcription?
Promoter sequences
What 2 DNA strands are involved in transcription elongation?
- Template strand
- Coding strand
What are the 3 types of RNA processing?
- Capping
- Polyadenylation
- Splicing
What do capping and polyadenylation protect against?
Degradation
What is polyadenylation and which end of the strand does it occur?
- Occurs at 3’ end
- polyA polymerase adds a string of A bases
What is splicing and how does it change mRNA?
- Removes introns between exons
- Turns pre-mRNA to mature mRNA
What are the 3 main types of RNA?
Ribosomal RNA (rRNA) Messenger RNA (mRNA) Transfer RNA (tRNA)
What is needed for translation to occur?
An adaptor molecule (tRNA)
What is the start and end point of translation?
4-letter DNA language to 20-letter protein language
What does translation produce?
An N to C polypeptide chain extension
How is an amino acid activated in translation?
- Amino acid binds to tRNA
- tRNA anticodon recognises mRNA codon
What recognises the amino acid and ATP in amino acid activation?
Enzyme
What is used in the termination step of translation?
Sequence specific stop codons
Which codon is recognised in the Initiation stage of translation?
AUG
Which organelle uses ATP to find the AUG codon?
Ribosome
What is formed in translation elongation?
Amino acids joined by peptide bonds
