The Nucleus
Does the nucleus contain the instructional manual for the cell?
The nucleus
acts as a control center of the cell. It contains chromatin, which is a complex of proteins (histones) and deoxyribonucleic acid which is abbreviated as DNA. The DNA contains all the information needed to make proteins. In fact, the nucleus of every human cell contains 23 pairs of chromosomes or 46 chromosomes. In general, a person inherits a copy of 23 chromosomes from the father and a copy of 23 chromosomes from the mother. Each chromosome contains a single molecule of DNA along with histones. DNA provides instructions on how to make specific types of proteins that are essential for the growth and maintenance of the human body. Therefore, DNA can be compared to the instructional manual for the cell.
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Click on the nucleus of the cell to see the parts of a nucleus in detail. |
However, if you look into the nucleus, you cannot see the double-stranded DNA. It is packaged as chromatin.
The chromatin is made of DNA, RNA, and nuclear proteins. Also, there is liquid inside the nucleus, the nucleoplasm, which contains chromatin and ribosomes.
Inside the nucleus, a structure called nucleolus is present. The nucleolus is not surrounded by a membrane. It is the center for the assembly of structures called ribosomes.
Ribosomes are made of two protein subunits and ribosomal RNA (rRNA).
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