resulted in constitutive lactase production, wouldn't it be independent of both lactose and glucose presence?
You are using an out of date browser. It may not display this or other websites correctly.
You should upgrade or use an alternative browser.
You should upgrade or use an alternative browser.
Ok, so if a lac operon mutation...
- Thread starter SwedishFish
- Start date
Do you mean, "would the lactase activity be dependant on both glucose and lactose?"
I don't see why that would be the case. Lactase breaks down lactose into galactose and glucose, so why would glucose be necessary for activity?
I don't really understand the question though, so if you could clear it up, maybe I could help you out better.
I don't see why that would be the case. Lactase breaks down lactose into galactose and glucose, so why would glucose be necessary for activity?
I don't really understand the question though, so if you could clear it up, maybe I could help you out better.
Originally posted by SwedishFish
resulted in constitutive lactase production, wouldn't it be independent of both lactose and glucose presence?
if it is constitutive it is independent per definition adn not dependent on any factor
noOriginally posted by Idle Mind
Do you mean, "would the lactase activity be dependant on both glucose and lactose?"
if it is constitutive it is independent per definition adn not dependent on any factor
that's what i thought
river-wind
Valued Senior Member
is lactase adversly effected by the presence of gloucose? I seem to remember that glucose inhibits lactase function, so that lactose conversion is regulated by the amount of gloucose already present.
ie
1)no glucose present=lactase works at full volume, glucose is produced.
2)as gluscose if produced, so of it binds to a secondary receptor on lactase, preventing it from doing it's job.=lactose->glucose conversion slows, as there is less functional lactase available
3)glucose (as long as it is not removed by cells for use) satuarates the area, inhibiting all the lactase, preventing any further lactose->glucose conversion
4)a cell uses some of the free glucose, equalibrium drives some of the glucose bound to lactase to become free, allowing the lactase to do more lactose->glucose conversion.
5)glucose saturates the area, inhibiting all the lactase...
hoever, as the question is not regulation of the lactose->glucose conversion rate, but that of the *creation* of lactase, then unless glucose or lactose is somehow able to act as an enzyme in the transcription process (which I'm pretty sure it's not), excess lactase creation due to mutation should not be effected by lactose or glucose presence.
But I studied this around 5 years ago, so I may be confused w/ a different system.
ie
1)no glucose present=lactase works at full volume, glucose is produced.
2)as gluscose if produced, so of it binds to a secondary receptor on lactase, preventing it from doing it's job.=lactose->glucose conversion slows, as there is less functional lactase available
3)glucose (as long as it is not removed by cells for use) satuarates the area, inhibiting all the lactase, preventing any further lactose->glucose conversion
4)a cell uses some of the free glucose, equalibrium drives some of the glucose bound to lactase to become free, allowing the lactase to do more lactose->glucose conversion.
5)glucose saturates the area, inhibiting all the lactase...
hoever, as the question is not regulation of the lactose->glucose conversion rate, but that of the *creation* of lactase, then unless glucose or lactose is somehow able to act as an enzyme in the transcription process (which I'm pretty sure it's not), excess lactase creation due to mutation should not be effected by lactose or glucose presence.
But I studied this around 5 years ago, so I may be confused w/ a different system.
Well anyway, there is a negative and positive control.
Positive control:
when Glucose is present the levels of cAMP go down (as a result of ATP production). cAMP interacts directly with the DNA at the site where RNA polymerase attatches and bends the DNA to a shape that the polymerase can attatch to.
So even if the operon is mutated and the negative control is faulty, the positive control will keep the production down in the presense of Glucose.
Negative control:
A repressor protein is translated and is de-activated in the presence of lactose. In a mutation the repressor protien doesn't "repress" production so the lac genes keep getting made.
Is that what you wanted?
Positive control:
when Glucose is present the levels of cAMP go down (as a result of ATP production). cAMP interacts directly with the DNA at the site where RNA polymerase attatches and bends the DNA to a shape that the polymerase can attatch to.
So even if the operon is mutated and the negative control is faulty, the positive control will keep the production down in the presense of Glucose.
Negative control:
A repressor protein is translated and is de-activated in the presence of lactose. In a mutation the repressor protien doesn't "repress" production so the lac genes keep getting made.
Is that what you wanted?
www.dictionary.com
con·sti·tu·tive P Pronunciation Key (knst-ttv, -ty-)
adj.
Making a thing what it is; essential.
Having power to institute, establish, or enact.
Of or relating to the synthesis of a protein or an enzyme at a constant rate regardless of physiological demand or the concentration of a substrate.
con·sti·tu·tive P Pronunciation Key (knst-ttv, -ty-)
adj.
Making a thing what it is; essential.
Having power to institute, establish, or enact.
Of or relating to the synthesis of a protein or an enzyme at a constant rate regardless of physiological demand or the concentration of a substrate.
old school!
i love how people answered questions i didn't ask. this, folks, is why you don't ask for homework help here. unless the monkey is answering of course.
i love how people answered questions i didn't ask. this, folks, is why you don't ask for homework help here. unless the monkey is answering of course.