Multiple Choice
In general, operons that encode the enzymes of a biosynthetic (anabolic) pathway (such as the trp operon) are __________, and those encoding the enzymes of a catabolic pathway (such as the lac operon) are __________.
16. Regulation of Expression
Review of the Lac Operon & Trp Operon
Struggling with General Biology?
Join thousands of students who trust us to help them ace their exams!Watch the first videoMultiple Choice
A bacterium can make the amino acid glycine or absorb it from its surroundings. A biochemist finds that glycine binds to a repressor protein and causes the repressor to bind to the bacterial chromosome, turning off an operon. If it is like other similar operons, the presence of glycine will result in the __________.
A
inhibition of bacterial cell division
B
breakdown of glycine
C
formation of sex pili
D
production of the repressor protein
E
cessation of the synthesis of glycine
Verified step by step guidance1
Understand the role of operons in bacterial gene regulation. Operons are clusters of genes under the control of a single promoter and are regulated by repressor proteins.
Recognize that the presence of glycine acts as a corepressor. When glycine binds to the repressor protein, it activates the repressor, allowing it to bind to the operator region of the operon.
Consider the effect of the repressor binding to the operon. This binding prevents RNA polymerase from transcribing the genes in the operon, effectively turning off the operon.
Identify the function of the operon in question. Since glycine binding turns off the operon, the operon is likely responsible for the synthesis of glycine.
Conclude that the presence of glycine leads to the cessation of the synthesis of glycine, as the operon responsible for its synthesis is turned off by the repressor-glycine complex.
6:24mWatch next
Master Review of the Lac Operon & Trp Operon with a bite sized video explanation from Jason
Start learningRelated Videos
Related Practice
Review of the Lac Operon & Trp Operon practice set
Problem sets built by lead tutorsExpert video explanations