Imagine that you have created a fusion between the Trp operon, which encodes the enzymes for tryptophan biosynthesis, and the Lac operon, which encodes the enzymes necessary for lactose utilization. Under which set of conditions (A–F below) will β-galactosidase be expressed in the strain that carries the fused operon?

A. Only when lactose and glucose are both absent.

B. Only when lactose and glucose are both present.

C. Only when lactose is absent and glucose is present.

D. Only when lactose is present and glucose is absent.

E. Only when tryptophan is absent.

F. Only when tryptophan is present.

#Question id: 12545

#Unit 10. Ecological Principles

#Question id: 12543

#Unit 10. Ecological Principles

Use Figure to answer the following questions. Examine this food web for a particular terrestrial ecosystem. Each letter is a species. The arrows represent energy flow.

Which species is most likely an omnivore?

#Question id: 11651

#Unit 10. Ecological Principles

Succession on a newly exposed site that was not previously occupied by soil and vegetation refers to

#Question id: 11652

#Unit 10. Ecological Principles

The sequence of changes initiated by disturbance is called succession, and the ultimate association of species achieved is called

#Question id: 11653

#Unit 10. Ecological Principles

Given some characteristics of the climax community

i) Tolerate its own reactions

ii) Tends to become mesic

iii) Less stable

iv) Complex stratification

v) Simple food web

vi) Less mutualism

vii) Gross production is equals to community respiration

viii) Net community production is zero

Which of the following combination shows the characteristics of climax community?

#Question id: 11654

#Unit 10. Ecological Principles

Succession start from the water body and continuos in community dyanamics, changes species composition as well as changes in structure also. Which one is the correct composition of hydrosere process?