What is the inducer molecule for the lac operon?
What does the inducer molecule do in an inducible operon?
If an inducer molecule is present, it binds to the repressor and changes its conformation so that it is unable to bind to the operator. This allows for expression of the operon. The lac operon is a negatively controlled inducible operon, where the inducer molecule is allolactose.
What is an inducer in genetics?
: one that induces especially : a substance that is capable of activating the transcription of a gene by combining with and inactivating a genetic repressor.
What is an inducer quizlet?
Inducer. Chemical which interacts with an active repressor protein and prevents repression, allowing RNA pol to transcribe gene. Activation. binding of a chemical which enhances likelihood of transcription.
What chemical reaction can the bacterial cells carry out as a result of lac operon expression?
The lac operon is then transcribed and translated into proteins including permease, which embeds itself into the cell membrane facilitating lactose transport into the cell, and β-galactosidase, which eats up lactose to make glucose molecules. β-galactosidase also makes allolactose.
Which of the following is required as inducer for the expression of lac operon?
In the presence of lactose, allolactose; an isomer of lactose, binds to the repressor and causes an allosteric shift. The altered repressor cannot bind to the operator, allowing RNA polymerase to transcribe the lac genes. Thus lactose is required for expression of the lac operon. The correct answer is C.
What is the structure of lac operon?
The lac operon consists of three structural genes: lacZ, which codes for β-galactosidase, which acts to cleave lactose into galactose and glucose; lacY, which codes for lac permease, which is a transmembrane protein necessary for lactose uptake; and lacA, which codes for a transacetylase that transfers an acetyl group …
Who proposed lac operon?
Why Lactose is considered an inducer in lac operon?
Lactose acts as an inducer in Lac operon by binding to the repressor protein, the repressor protein is produced by the inhibitory gene (LacI) present upstream to the operon gene. So a negligible amount of other proteins from the Z,Y and A genes are produced.
What kind of molecule is the lac repressor?
Is Lactose a repressor?
Abstract. The lactose repressor protein (LacI), the prototype for genetic regulatory proteins, controls expression of lactose metabolic genes by binding to its cognate operator sequences in E. coli DNA.
Is lactose an inducer?
These few lactose molecules are converted into an active form which acts as an inducer and binds with the repressor, a product of the regulator gene. The three structural genes are expressed as three enzymes to metabolise lactose to galactose and glucose. Lactose, thus, acts as the inducer for its own breakdown.
What does the lac repressor do quizlet?
the lac repressor protein is active and binds to the lac operator site. Allowing RNA polymerase to bind to promoter and transcribes a polycistronic mRNA containing the Lacz, Lacy, and Laca genes.
What does the inducer bind to in the lac operon quizlet?
In the case of the lac operon, lactose is the inducer. If lactose is present, it binds to and inactivates the repressor by causing it to fall off the operator. If lactose operator is free of repressor, then RNA Polymerase is able to bind. The operon is induced when lactose molecules bind to the repressor protein.
Which type of mutation leads to a frameshift mutation quizlet?
A frameshift mutation (also called a framing error or a reading frame shift) is a genetic mutation caused by indels (insertions or deletions) of a number of nucleotides in a DNA sequence that is not divisible by three.
Which kind of mutation has the least impact on an organism?
What is the difference between a point mutation and a frameshift mutation?
Chromosomal alterations are mutations that change chromosome structure. Point mutations change a single nucleotide. Frameshift mutations are additions or deletions of nucleotides that cause a shift in the reading frame.