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: 5291

#Unit 8. Inheritance Biology

A number of nutritional mutant strains were isolated from wild-type Neurospora that responded to the addition of certain supplements in the culture medium by growth ( + ) or lack of growth ( -). Given the following responses for single gene mutations, diagram a metabolic pathway that could exist in the wild-type strain that is most consistent with the data. Indicate where the pathway is blocked in each mutant strain.

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#Question id: 2455

#Unit 2. Cellular Organization

Cofilin:

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#Question id: 3268

#Unit 11. Evolution and Behavior

A population of insects is in Hardy-Weinberg equilibrium for a gene with alleles A = orange and a = yellow eyes. There are 91% orange and 9% yellow individuals in the population. If the fitness of the yellow phenotype suddenly drops to zero, what will be the allele frequency in the next generation?

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#Question id: 26432

#Unit 3. Fundamental Processes

If the mismatch is near 3’ then which of the following will degrade strands of DNA in the 5’ → 3’ direction only

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#Question id: 28467

#Unit 5. Developmental Biology

Mammals exhibits which type of cleavage?