TLS Online TPP Program

#Question id: 12968


Most terrestrial ecosystems have a pyramidal structure of where biomass of producers > primary consumers > secondary consumers > tertiary consumers. However, some aquatic ecosystems have an inverted pyramidal structure where the standing biomass of producers < primary consumers. An explanation for this is:

#Unit 10. Ecological Principles
  1. Greater efficiency of primary consumers in aquatic ecosystems 
  2. High turnover rates of aquatic producers relative to consumers 
  3. Low nutrient concentrations in aquatic ecosystems
  4. Very high light limitation in aquatic ecosystems
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TLS Online TPP Program

#Question id: 4510

#Unit 3. Fundamental Processes

Which statements are true about group I and group II introns,

A. Group I (and II) introns are not enzymes because they have a turnover number of only 1.

B. A third transesterification reaction can occur to cyclize the intron.

C. They cannot be readily converted into ribozymes.

D. It is similar to the way that the self-cleaving Hammerhead could be converted to a ribozyme by separating the active site from the substrate

TLS Online TPP Program

#Question id: 4511

#Unit 3. Fundamental Processes

The proteins are not needed for the splicing reaction itself, because

TLS Online TPP Program

#Question id: 4512

#Unit 3. Fundamental Processes

Some pre-mRNAs can be spliced in more than one way. Thus, mRNAs containing different selections of exons can be generated from a given pre-mRNA, called

TLS Online TPP Program

#Question id: 4513

#Unit 3. Fundamental Processes

Different snRNPs recognize the same (or overlapping) sequences in the pre-mRNA at different stages of the splicing reaction, which two snRNPs recognizing the 5’ splice site

TLS Online TPP Program

#Question id: 4514

#Unit 3. Fundamental Processes

What is true about coactivators,

A. The coactivators act directly by binding to the DNA

B. The coactivators act indirectly—not by binding to the DNA

C. Are required for essential communication between the activators and the complex composed of Pol II.

D. Are required for essential communication between the and the basal (or general) transcription factors.

TLS Online TPP Program

#Question id: 4515

#Unit 3. Fundamental Processes

Transcription Activators are,

A. Known to facilitate transcription at hundreds of promoters,

B. Specific for a few promoters,

C. Sensitive to the binding of signal molecules,

D. Providing the capacity to activate or deactivate transcription in response to a changing cellular environment.