Practice Questions

TLS Online TPP Program

#Question id: 3982

The diagram below represents a hypothetical operon in the bacterium E. coli. The operon consists of two structural genes (A and B) that code for the enzymes A-ase and B-ase, respectively, and also includes P (promoter) and O (operator) regions as shown.

When a certain compound (X) is added to the growth medium of E. coli, the separate enzymes A-ase and B-ase are both synthesized at a 50-fold higher rate than in the absence of X (which has a molecular weight of about 200). Which one of the following statements is true of such an operon?

#Unit 3. Fundamental Processes

Adding X to the growth medium causes a repressor protein to be released from the O region.
Adding X to the growth medium causes a repressor protein to bind tightly to the O region.
Synthesis of the mRNA from this operon is not changed by the addition of compound X.
The mRNA copied from this operon will be covalently linked to a short piece of DNA at the 5' end.

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TLS Online TPP Program

#Question id: 24571

#Unit 10. Ecological Principles

In which case the population eventually decline to extinction?

TLS Online TPP Program

#Question id: 24572

#Unit 10. Ecological Principles

Find out the characteristics of geometric growth?

a. It can grow for both periodic and continuous breeders

b. depends on the activity of net reproductive growth rate

c. unlimited Population Growth Leads to J-shaped

d. unlimited Population Growth Leads to S-shaped

e. resources are not limited

TLS Online TPP Program

#Question id: 24573

#Unit 10. Ecological Principles

Calculate the finite rate of increase, if ecologists count the number of birds in the population, N0= 100, the next year ecologists count 110 birds in the same population,

TLS Online TPP Program

#Question id: 24574

#Unit 10. Ecological Principles

If number of birds in the population N0= 100 next year ecologists count 110 birds in the same population, consider a population of birds growing at a rate of 5% per year. After 5 years how many birds would there be?

TLS Online TPP Program

#Question id: 24575

#Unit 10. Ecological Principles

If the initial population size 1000 then given population birth rate is 0.55, and death rate is 0.45, then calculate the change in population per unit time?

TLS Online TPP Program

#Question id: 24576

#Unit 10. Ecological Principles

The birth of 100 cockroaches to a population of 1,000 would represent a birth rate. Similarly, the death of 50 cockroaches in a population of 1,000 would be a death rate, d, per individual per week. Calculate the rate of change in a population per unit time ?