Organisms evolve over generations to become adapted to the environmental conditions to which they are exposed. The diversity of organisms that

occurs in any particular area thus may be largely determined by the abiotic factors limiting survivorship and reproduction of organisms in a region. Which of the following limit the range of Saguaro cactus in North America?

I) pollinators

II) sunlight

III) precipitation

IV) temperature

#Question id: 13019

#Unit 10. Ecological Principles

#Question id: 2902

#Unit 2. Cellular Organization

The function and positioning of the histone variants can be studied by an application of technologies used in genomics. One useful technology is chromatin immunoprecipitation, or chromatin IP (ChIP). The correct sequence of the processes that occur in this experiment will be?

1. A histone variant with an epitope tag is introduced into a particular cell type, where it is incorporated into nucleosomes.

2. The pattern of hybridization on the microarray reveals the DNA sequences bound by the nucleosomes with the histone variant.

3. Antibody is added, and the nucleosomes containing the epitope-tagged histone variant are selectively precipitated.

4. Chromatin is isolated from the cells and digested briefly with micrococcal nuclease (MNase).

5. The DNA in these nucleosomes is extracted from the precipitate, labeled, and used to probe a microarray representing all or part of the genomic sequences of that particular cell type.

#Question id: 10348

#Unit 6. System Physiology – Plant

During ammonium assimilation, requires two enzymes converting ammonium to amino acids. Each of which is Glutamine synthetase (GS), given below some statements about GS ;

a) GS transfers the amide group of glutamine to 2-oxoglutarate, yielding two molecules of glutamate

b) it requires a divalent cation such as Mg2+, Mn2+, or Co2+ as a cofactor

c) Plants contain two classes of GS, one in the cytosol and the other in root plastids or shoot chloroplasts

d) The cytosolic forms are expressed in germinating seeds or in the vascular bundles of roots and shoots and produce glutamate for intercellular nitrogen transport

e) The GS in root plastids generates amide nitrogen for local consumption; the GS in shoot chloroplasts reassimilates photorespiratory NH4+

f) Light and carbohydrate levels alter the expression of the cytosolic forms of the enzyme, but they have little effect on the plastid forms.

Which of the following statements is correct?

#Question id: 11271

#Unit 10. Ecological Principles

Autotrophs in the aquatic ecosystem, unlike their counterparts in the terrestrial ecosystem are mostly microscopic and very low in indigestible (to the herbivores) matter. Following some observation are given? 

A) Tropic level transfer efficiency is greater in aquatic ecosystem than terrestrial ecosystem  

B) Tropical forest herbivores have higher consumption efficiencies than grassland herbivores

C) Flow of energy and nutrient is rapidly in aquatic ecosystem than terrestrial

D) Production efficiency of higher tropic level is greater than lower tropic level

#Question id: 4010

#Unit 3. Fundamental Processes

In a cell that produces only one type of protein, which of the following statements about the relationship between hnRNA and mRNA is true?