Operons and Prokaryotic Gene Regulation
What is an operon?
A group of genes controlled together
What process copies DNA into RNA?
Transcription
Where does translation occur?
Ribosome
What is a mutation?
A change in DNA sequence
What proteins help package DNA in eukaryotic cells?
Histones
Which operon is activated when lactose is present?
lac operon
What enzyme performs transcription?
RNA polymerase
What molecule carries amino acids to the ribosome?
tRNA
What type of mutation changes one nucleotide?
Point mutation
What is the main purpose of gene regualtion?
To control gene expression
What molecule binds to the operator to block transcription
Repressor protein
Where does transcription occur in eukaryotic cells?
Nucleus
What is the role of mRNA translation?
It carries genetic instructions from DNA to the ribosome
What mutation introduces a premature stop codon?
Nonsense mutation
Why do different cell types express different genes?
Why is the lac operon considered an inducible operon?
It is normally off and turns on when lactose is present
How could a mutation in the promoter region affect protein production?
RNA polymerase may not bind correctly, reducing transcription and protein production
How does the ribosome know which amino acid to add next during translation?
tRNA anticodons pair with mRNA codons
Why are silent mutations often harmless?
They do not change the amino acid sequence
How does DNA methylation usually affect transcription?
It decreases or silences transciption
How would a mutation preventing the repressor from binding to the operator affect the lac operon?
The operon would stay on continuously
What is the role of the promoter during transcription?
It is the binding site for RNA polymerase
How could a frameshift mutation drastically change a protein's structure?
It shifts the reading frame, changing many amino acids after the mutation
How can mutations in regulatory genes affect multiple genes at once?
Regulatory genes control the expression of many other genes
Why is precise gene regulation essential during embryonic development?
Different genes must turn on/off at specific times for proper cell specialization and development