Unknown Operon 4. The mmm operon, which has sequences A, B,...

Unknown Operon 4. The mmm operon, which has sequences A, B, C, and D (which might be structural genes or regulatory sequences), encodes enzymes 1 and 2. Mutations in sequences A, B, C, and D have the following effects, where a plus sign (+) indicates that the enzyme is synthesized and a minus sign (-) indicates that the enzyme is not synthesized. Mutation in sequence | Mmm absent | Mmm present | Enzyme 1 | Enzyme 2 | Enzyme 1 | Enzyme 2 No mutation | + | + | - | - A | - | + | - | - B | + | + | + | + C | + | - | - | - D | - | - | - | - a) Is the mmm operon inducible or repressible? b) Indicate which sequence (A, B, C, or D) represents the operon components: • Regulator gene ______ • Promoter ______ • Enzyme 1 gene ______ • Enzyme 2 gene ______

Transcript

00:01 Hello students.

00:02 Today's question is about we have m m m -operon and it has a, b, c, d sequence.

00:08 But we do not know where are the structural genes, where are the regulatory genes.

00:13 And they encode the enzyme, enzyme one and two.

00:17 They encode enzyme one and two.

00:19 And mutations have the following effect.

00:22 So this is m -m -m -apsent and this is m -m -m -p present.

00:26 So the question is about, the question is about here we have no mutations.

00:30 Here we have a, b, c, d.

00:33 So this is a sequence and this is the enzyme one function, enzyme two function, enzyme one function, enzyme one function and enzyme two function.

00:39 So we have to tell whether it is inducible or whether it is repressible.

00:44 So we have to find the correct answer.

00:46 So as we can see that when we have no mutation, so this is the normal scenario.

00:54 This is the normal scenario.

00:56 So in this case, we can see that when enzyme 1 and enzyme 2, are present when there is no mutation mmm is absent but in this scenario when these both two enzymes are absent when they are absent means not working but operon is present operon is present we can see that this is repressible this is repressible operon is a repressible it cannot be undusible when there is no mutations when no mutations when enzyme one and two are not produced.

01:36 When enzyme one and two are not synthesized or not produced, we can see that.

01:44 We can see that it is in the presence of the mmm.

01:48 It is in the presence of mmm.

01:51 But they are produced.

01:54 But enzyme one and enzyme two are produced.

02:00 In the absence of mmm in the absence of mmm operon.

02:05 In the absence of mmm operon.

02:07 So it cannot be the inducible.

02:10 So there is no chance that this one is the inducible.

02:14 So it cannot be the inducible.

02:15 So next we have to find where is regulatory gene.

02:19 Where is a regulatory gene? so regulatory gene is at the b.

02:24 How is at the b? so we know that the regulatory gene in a repressible operon.

02:29 In the repressible operand which work to repress it.

02:36 So in the b case, we can see that.

02:39 In the b case we can see that enzyme 1 and 2 are being produced.

02:44 But mmm is absent...

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