Q:

What is the function of a nucleolus?

A:

Quick Answer

The function of the nucleolus is to transcribe DNA into ribosomal RNA and assemble rRNA into ribosomal subunits. The creation of rRNA is important because rRNA makes up ribosomes which are responsible for protein synthesis in the cell.

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What is the function of a nucleolus?
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Full Answer

In order for transcription to occur, a protein called RNA polymerase binds to DNA at its promoter region. Transcription factors and proteins pull apart DNA's double helix so that polymerase can then transcribe one strand of the DNA to create single-stranded RNA. Transcription ends when polymerase reaches a terminator sequence on the DNA.

When DNA is transcribed into rRNA in the nucleolus, three or four (depending on the organism) distinct rRNAs are produced. These rRNAs are combined with proteins in order to assemble a large ribosomal subunit and a small ribosomal subunit. The subunits are then exported from the nucleolus and nucleus to the endoplasmic reticulum and the cell's cytosol in order to carry out the process of translation, or protein synthesis.

Nucleoli are made of proteins, DNA and RNA and are contained within the cell's nucleus. They don't have membranes, so they can disassemble when the cell divides during mitosis. While humans only have one nucleolus per cell, other organisms exist that can have cells containing multiple nucleoli.

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Related Questions

  • Q:

    What is a good analogy for the functioning of the nucleolus?

    A:

    The best analogy for the nucleolus in eukaryotic cells is a factory that makes tools that are used to build other resources. The primary function of the nucleolus is to combine and construct ribosomes. The primary function of ribosomes is to build proteins necessary for the cell.

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  • Q:

    Where are ribosomes made?

    A:

    According to Florida State University, ribosomes are primarily constructed in the nucleolus of all living cells. Inside the nucleolus, four strands ribosomal RNA (rRNA) bind together with ribosomal proteins. This results in two structures, called the small ribosome subunit and the large ribosome subunit. Both of these subunits travel through pores in the nucleus and enter the free space of the cell.

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  • Q:

    What is a nucleolus?

    A:

    A nucleolus is a substructure composed of nucleic acids and proteins that is found within the nucleus of a cell. Known as the ribosome production factory, malfunction of the nucleolus has been found to cause disease in humans.

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  • Q:

    What is the physical description of the nucleolus?

    A:

    The nucleolus is found in the nucleus of a cell and appears as a dark spherical region when seen through a microscope. The nucleolus is one of the largest physical structures within the nucleus and can occupy up to a quarter of its total volume.

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