Video Transcript
What is the function of the nucleoplasm? (A) It supports the chromatin and the nucleolus and helps maintain the shape of the
nucleus. (B) It holds two chromatids together by proteins at a region of the chromosome. (C) It regulates the transport of molecules across the cell wall. (D) It separates the nucleus from the cytoplasm.
One of the defining characteristics of eukaryotic cells is the presence of the
nucleus to contain DNA. Let’s take a closer look at the nucleus and describe some of its parts so we can
answer our question.
The nucleus is surrounded by an inner and outer membrane that together make up the
nuclear envelope. The nuclear envelope separates the contents of the nucleus from the rest of the
cell. This protects DNA from any reactions that are occurring in the cytoplasm. The outer membrane is continuous with the endoplasmic reticulum which you can see
here. Only a portion of it is shown for simplicity, but the endoplasmic reticulum surrounds
the whole nucleus. Surrounding the nuclear envelope are numerous openings called nuclear pores. These allow small substances, like mRNA, to exit the nucleus while keeping larger
substances, like DNA, inside the nucleus.
Inside the nucleus is the DNA and its chromosomes that are compacted in a state
called chromatin. Chromatin is a mixture of DNA and histone proteins. The nucleolus is a region of the nucleus where ribosome subunits are produced. Here, there’s a lot of proteins, RNA, and DNA that are responsible for assembling
ribosomes. Because of the high amount of material in the nucleolus, it’s usually easily seen
using a microscope. And finally, the gel-like fluid that contains the chromatin and the nucleolus is
called the nucleoplasm. This fluid supports these structures and helps maintain the shape of the nucleus. It also contains all the enzymes and nucleotides needed for DNA transcription.
Getting back to our question, the function of the nucleoplasm is given by answer
choice (A). It supports the chromatin and the nucleolus and helps maintain the shape of the
nucleus.
