miRNAs are encoded in the genome as segments of longer transcripts. Their characteristic structure helps identify them and predict the target genes they might regulate. Which of the following are the characteristic features of these small RNA molecules?

I. The functional form of an miRNA is typically 21 or 22 nucleotides (it can vary from 19 to 25 nucleotides).

II. The first cleavage liberates the stem-loop, called the pre-miRNA; the second generates the mature miRNA from the pre-miRNA.

III. The pre-miRNAs can be encoded by any part of a transcript: that is, they might fall within coding regions, within leader regions, or within Introns.

IV. The base pairing between miRNA and target RNA is initiated by interactions of so-called seed residues—the sequence between bases 2 and 9 of the 22-nucleotide miRNA.

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#Question id: 17265

#Unit 11. Evolution and Behavior

Match the geological time period with the diversification events associated with them:

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#Question id: 17266

#Unit 11. Evolution and Behavior

First human social life in vertebrates and decline of woody plants appeared in ____

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#Question id: 17267

#Unit 8. Inheritance Biology

In humans, albinism (unpigmented skin, hair, and eyes) is due to an enzymatic deficiency, and it is an autosomal recessive trait. Suppose that in a small country of one million people (“Generation 1”), there are 500 aa albinos and 9000 Aa heterozygous carriers. Estimate q, the frequency of allele a, in Generation 1. Show your calculations. 

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#Question id: 17268

#Unit 8. Inheritance Biology

In humans, albinism (unpigmented skin, hair, and eyes) is due to an enzymatic deficiency, and it is an autosomal recessive trait. Suppose that in a small country of one million people (“Generation 1”), there are 500 aa albinos and 9000 Aa heterozygous carriers. Estimate p, the frequency of allele A, in Generation 1?

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#Question id: 17269

#Unit 8. Inheritance Biology

In humans, albinism (unpigmented skin, hair, and eyes) is due to an enzymatic deficiency, and it is an autosomal recessive trait. Suppose that in a small country of one million people (“Generation 1”), there are 500 aa albinos and 9000 Aa heterozygous carriers. In the next generation of 1 million individuals (Generation 2), what are the expected numbers of aa albinos and Aa carriers? (Assume random mating and all other HardyWeinberg conditions.)

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#Question id: 17270

#Unit 13. Methods in Biology

which of the following are the three important components of Electrophoresis