Answer:
The miRNAs act as post-transcriptional silencers, as they are similar to specific mRNAs and regulate their stability and translation. They are small endogenous non-coding ribonucleic acid (RNA) molecules, with about 22 nucleotides, which act as regulators of gene expression in plants and animals, at the post-transcriptional level through the cleavage of a target messenger RNA (mRNA) or repression of translation.
In general, most miRNA genes are transcribed by RNA polymerase II in the nucleus in primary miRNAs (pri-miRNAs). Individually, a pri-miRNA can produce a single miRNA or contain groups of two or more miRNAs that are processed from a common primary transcript. These long pri-miRNA are cleaved by a complex comprising the double-stranded RNAse III enzyme (DROSHA) and its essential cofactor, the binding protein DGCR8 (DiGeorge Syndrome Critical Region 8 protein) in mammals. DROSHA contains two domains of RNAse III, each of which cleaves a strand of the RNA resulting in the precursor microRNA (pre-miRNA) with about 70 base pairs, which contains a double-stranded stretch and a single-stranded loop, forming a structure in clamp. The pre-miRNA is exported to the cytoplasm by the protein exportin-5 (XPO-5), where it is cleaved by DICER1, an RNAse III that assesses the 3 'and 5' ends of the pre-miRNA, generating a mature miRNA with about 22 nucleotides. The processing of pre-miRNA by Dicer promotes the unfolding of the RNA duplex in the form of a clamp. The position in the formation of the clamp can also influence the choice of tape.
Explanation:
Amoebas are single-celled organisms, which means that they are composed of just one cell. Each amoeba is a cell capable of performing all living functions by itself. They can reproduce asexually. They are protozoans with no fixed shape. Most have no hard parts and look like blobs of jelly.
Answer:
Option D
Explanation:
The cornea is one of the most sensitive tissues of the body, as it is densely innervated with sensory nerve fibres via the ophthalmic division of the trigeminal nerve by way of 70–80 long ciliary nerves. Hence the answer would be option D.
Answer:
The gray matter in the spinal cord is located in the <u><em>grey column</em></u> , and its shape resembles a letter H, or a butterfly. The cell bodies of somatic motor neurons are primarily housed in the <u><em>ventral or anterior</em></u> horns, which innervate skeletal muscle.
Explanation:
The grey matter is a component of the central nervous system that contains neuronal and glial cells and it can be found in the brain, brainstem and <em>spinal cord, in this last one, is found in the grey column, a mass of grey matter shaped in H form.</em>
In this column the grey matter is divided into four columns (as you can see in the image I added):
- The dorsal or posterior horn: contains somatosensorial neurons
- <em> The ventral or anterior horn: contains somatic efferent motor neurons (they exit the spinal cord to innervate skeletal muscle) </em>
- The intermediate column: contains neurons to innervate visceral organs
- The lateral horn: same as the intermediate column
I hope you find this information useful and interesting! Good luck!
Less of the sugars produced in the leaves is used making cellulose, the structural molecule that supports stems in herbaceous plants. As a result, more is free to be stored in grain in the form of starch. Hope this helps! :D<span>
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