DNA to Protein Flashcards
You and your friend both have a chromosome 12. Do you have the same genes in the same location?
Yes
What is the link between genotype and phenotype?
Proteins
What are the two stages of gene expression and what happens here?
Two stages: transcription and translation. DNA directs protein synthesis.
What is the central dogma of biology? (Illustrate)
DNA –(Transceiption)–> RNA –(Translation)–> Protein
What is the difference between transcription and translation in prokaryotic vs eukaryotic cells?
In prokaryotic cells, transcription and translation happen in the same place at the same time; whereas in eukaryotic cells, transcription happens inside the nucleus and translation happens in cytoplasm.
What are the stages of transcription?
Initiation, Elongation and Termination
What are the steps in transcription?
RNA polymerase binds to promoter on template strand; reads 3’ to 5’, unwinding DNA; and dissociates when it reaches stop codon
Where does RNA poly II bind to?
Template strand
What happens in the elongation of the RNA strand?
As RNA polymerase moves along DNA, it untwists the double helix 10-20 bases at a time.
True or False. Only one strand can be the template.
False! either strand can be the template
What is the purpose of RNA splicing?
Splicing removes introns, joins exons, and creates mRNA with continuous coding sequence.
How does splicing works?
Small RNAs recognize splice sites
Why do we have introns?
They contain sequences that may regulate gene expression
Define intron and exon.
Intron means interleaving sequence (in between sequence) and exon means expressed sequence.
Whta is true about 5’ and 3’ UTRs?
They are part of the exon, transcribed but not translated.
What shape does tRNA have and why is that?
Because of hydrogen bonds, tRNA molecules actually have 3D conformation, roughly L-shaped.
What 2 steps does an accurate translation require?
Correct match between tRNA and amino acid, catalyzed by aminoacyl-tRNa synthetase; and correct match between tRNa anticodon and mRNA anticodon
What is the function of eukaryotic ribosomes?
Facilitate coupling of tRNA anticodons with mRNA codons
Whta are the three-binding sites for tRNA?
A site, P site and E site
What happens in the initiation of translation?
Proteins called “initiation factors” bring in large subunit and this completes the translation initiation complex
What happens in the elongation of translation?
Amino acids are added to preceding AA at the C-terminus of the growing chain
What are the three steps in elongation of translation? (CPT)
Codon recognition, peptide bond formation, and translocation
When does termination of translation occur?
It occurs when stop codon in mRNA reaches the A site
What is the purpose of release factor?
It causes the addition of H2O instead of an AA
