Nucleus - Structure & Function

The nucleus is an important organelle responsible for controlling nearly all forms of cellular activities. Almost every kind of cell in existence is classified based on the presence or absence of the nucleus within its cell (classified either as a eukaryotic or prokaryotic cell.)

What is a Nucleus?

The most integral component of the cell is the nucleus (plural: nuclei). It is derived from a Latin word which means “kernel of a nut”.

Nucleus Definition: A nucleus is defined as a double-membraned eukaryotic organelle that contains the genetic material.

Nucleus

A nucleus diagram highlighting the various components. Moreover, only eukaryotes have the nucleus, prokaryotes have the nucleoid

As stated above, the nucleus is found only in eukaryotes and is the defining characteristic feature of eukaryotic cells. However, some cells such as RBCs do not possess a nucleus though they originate from a eukaryotic organism.

More to Explore: Difference Between Nucleus and Nucleoid

Nucleus Structure

  • It is generally the most prominent organelle in the cell.
  • The nucleus is completely bound by membranes.
  • It is surrounded by a structure called the nuclear envelope.
  • This membrane separates the contents of the nucleus from the cytoplasm.
  • The cell’s chromosomes are also enclosed within it.
  • DNA is present in the Chromosomes and they provide the genetic information required for the creation of other cell components and also for reproduction of life.

Nucleus Function

  • It contains the cell’s hereditary information and controls the cell’s growth and reproduction.
  • The nucleus has been clearly explained as a membrane-bound structure that comprises the genetic material of a cell.
  • It is not just a storage compartment for DNA but also happens to be the home of some essential cellular processes.
  • First and foremost, it is possible to duplicate one’s DNA in the nucleus. This process has been named DNA Replication and creates an identical copy of the DNA.
  • Creating two identical copies of the host or body is the first step in cell division, where each new cell will get its own set of instructions.
  • Secondly, the nucleus is the spot of transcription. Transcription is the process of creating different types of RNA from DNA. Transcription would be a lot like making copies of individual pages of the human body’s instructions that can then be passed out and read by the rest of the cell.
  • The central rule of biology states that DNA is copied into RNA, which is then turned into protein.

Further Reading:

Important Questions on the Nucleus

1. What is the nucleus?

The nucleus is a double-membraned organelle that contains the genetic material and other instructions required for cellular processes. It is exclusively found in eukaryotic cells and is also one of the largest organelles.

2. Outline the structure of the Nucleus.

  • A structure called the nuclear envelope/ nuclear membrane surrounds the nucleus. It is a double-membraned organelle.
  • Within the nucleus lies the nucleolus, which takes up 25% per cent of the volume.
  • Also found within the nucleus are dense, thread-like structures called chromatins that contain DNA and proteins.
  • The mechanical strength for the nucleus is provided by the nuclear matrix, a network of fibres and filaments which performs functions similar to the cytoskeleton.

3. Highlight the functions of the nucleus.

The nucleus has 2 primary functions:

  • It is responsible for storing the cell’s hereditary material or the DNA.
  • It is responsible for coordinating many of the important cellular activities such as protein synthesis, cell division, growth and a host of other important functions.

Discover more about the Nucleus or any other related topics by registering at BYJU’S biology.

Practise This Question

Which of the following pairs of cell organelles work together to package macromolecules?

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