Mutations
This type of point mutation changes one amino acid to a different amino acid.
Missense mutation
This molecule serves as the RNA polymerase binding site in bacterial operons.
Promoter
These are the coding sequences of a gene that are kept in the final mRNA after splicing
Exons
Mutations that occur in germ cells can affect the next generation; mutations in these cells cannot.
Somatic cells
This part of an operon is where the repressor protein physically binds to block transcription.
Operator
A frameshift mutation caused by losing one or more nucleotides is called this.
Deletion
In the trp operon, this molecule acts as a corepressor that activates the repressor protein.
Tryptophan
These non-coding sequences are removed from pre-mRNA before it leaves the nucleus.
introns
In eukaryotes, this distant DNA control sequence binds activator proteins to boost transcription far above baseline.
Enhancer
A repressible operon is typically found in this type of metabolic pathway — one that builds molecules.
Anabolic (biosynthetic) pathway
This type of point mutation has no effect on the amino acid sequence due to redundancy in the genetic code.
Silent mutation
The lac operon is an example of this type of operon because a nutrient turns gene expression ON.
Inducible operon
A single gene can produce multiple different proteins by including or excluding different exons during this process.
Alternative RNA splicing
Both the trp repressible operon and DNA methylation in eukaryotes share this outcome.
They both turn off / repress gene transcription
In the lac operon, this specific molecule binds to the lac repressor and causes it to release the operator.
Allolactose (a derivative of lactose)
This chromosomal mutation type involves a segment being flipped 180° and reinserted.
Inversion
Francois Jacob and Jacques Monod coined this term for a cluster of related bacterial genes under one promoter.
Operon
Ubiquitin-tagged proteins are degraded in this cellular structure.
Proteasome
Name all 3 categories of base-pair substitution mutations and define each in one phrase.
Silent (no amino acid change), missense (different amino acid), nonsense (creates a premature stop codon)
The trp operon is normally ON (transcribing) when tryptophan levels are low. Name the protein that is produced but remains inactive until tryptophan binds it.
The trp repressor protein
A frameshift insertion of exactly 3 nucleotides causes this specific consequence instead of a frameshift.
Addition of one extra amino acid with no reading frame shift
In both the trp and lac operons, the small molecule regulator works by causing this molecular event in the repressor protein.
A conformational (allosteric) change in the repressor protein
Histone acetylation activates transcription by doing this to chromatin structure.
Loosens/unwinds DNA from histones, making genes accessible to transcription factors
A eukaryotic cell uses alternative RNA splicing of the same pre-mRNA transcript to accomplish this.
Produce a family of different proteins from a single gene
Explain why an inducible operon is more energy-efficient than constitutive expression for a catabolic enzyme like β-galactosidase.
The cell only produces the enzyme when its substrate (lactose) is present, avoiding wasting energy and resources making a protein that has nothing to break down