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Describe how the lac operon works when lactose is both present and absent.

When lactose is absent the lac operon is switched off. This is becasue a repressor protein is produced which binds to the operator region. This prevetns RNA polymerase from binding to the operon and there...

SE
Answered by Suzannah E. Biology tutor
27523 Views

Find the indefinite integral of sin(2x)(cos^2(x)) with respect to x.

We know from trigonmetric identities that cos(2x) = 2cos^2(x) -1, therefore cos^2(x) = 0.5(1+cos(2x)).

Subbing this in gives the following integrand: 0.5(1+cos(2x))sin(2x).

We can now split ...

PP
Answered by Patrick P. Maths tutor
5677 Views

An alcohol, X has an Mr of 74 and percentage composition of 64.9% Carbon, 13.5% Hydrogen and 21.6% Oxygen. It does not turn potassium dichromate (VI) green. Determine the structural formula of X, and state its name.

64.9/12 = 5.40833

21.6/16 = 1.35

5.40833/1.35 = 4 so 4 Carbons

13.5/1.35 = 10 so 10 Hydrogens

1.35/1.35 = 1 so 1 Oxygen

4x12+10+16 = 74 so emperical formula = Molecular ...

MB
Answered by Megan B. Chemistry tutor
9338 Views

A hollow sphere of radius r is being filled with water. The surface area of a hemisphere is 3pi*r^2. Question: When the water is at height r, and filling at a rate of 4cm^3s^-1, what is dS/dT?

By the chain rule ds/dt = ds/dr * dr/dv * dv/t. At a height of r, the water fills a hemisphere. So ds/dr = 6pir. dr/dv = 1/(dv/dr), so we need to find dv/dr. Students should have the formula for the v...

HB
Answered by Henry B. Maths tutor
5915 Views

Describe in Italian what you like to do in your spare time

Nel tempo libero mi piace andare a correre, fare delle lunghe passeggiate in montagna e leggere. Di solito vado a correre due volte alla settimana, mi aiuta a rilassarmi e a mantenermi in forma. Nel fine ...

PC
Answered by Paolo C. Italian tutor
2100 Views

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