More of the same protein is not a new protein
- The idea
- Predict
- See it
- Why
- Check
The idea
“Making more or less of a protein changes the protein. A lower band on a gel means less of it.”
Both kinds of change make two samples look different, so they blur together. A lower band on a gel can look like a weaker result.
The short version
The mistake: Making more or less of a protein changes the protein. A lower band on a gel means less of it.
What's actually true: Transcription rate and gene copies change how much is made. Splicing or a coding mutation changes which product it is.
- Faster transcription makes more copies of the same mRNA, so ribosomes build more of the same polypeptide.
- A different product needs a different message. Alternative splicing joins a different set of exons, and a mutation can change the coding sequence.
On the exam: Did the molecule change, or just how many copies? On a gel, distance is size and brightness is amount.