To better understand how our bodies function, we need to better understand how a cell and its nucleus work. Here’s a crash course on this.
Now, you might already know that the center of the cell, the nucleus, it’s like a command center that controls cell growth, division, or death. But there’s more about it.
To find out about the nucleus and its functions, we first need to dive into the basic unit of any living creature — a cell.
What Is The Cell?
The cell is the basic building block of any living organism. Cells are responsible for providing structure for the body, receiving nutrients, converting them into energy, and performing specialized functions.
There are organisms consisting of one cell only and those consisting of many more.
There are also two types of cells — eukaryotic and prokaryotic. Eukaryotic cells are the basis of protists, plants, fungi, and animals, while prokaryotic cells make up the organisms of bacteria and archaea.
Within each cell are structures called organelles — mitochondria, endoplasmic reticulum, and the nucleus. The nucleus is the largest organelle in a cell, and it marks the difference between eukaryotic and prokaryotic cells.
Prokaryotic cells do not have a nucleus. They have a nucleoid region that has no membrane dividing it from the rest of the cell.
However, eukaryotic cells contain the nucleus, as well as the cell membrane and the cytoplasm. Other membrane-bound organelles in eukaryotes include mitochondria, chloroplasts, ribosomes, endoplasmic reticulum, and the Golgi apparatus.
What Is The Nucleus?
The nucleus is the largest organelle in a cell, spherical or round. Its size varies from 5 to 10 microns in diameter. Despite its small size, it contains about 6 feet of DNA.
Usually, there is only one nucleus per cell. But certain organisms, such as slime molds or certain groups of algae, have thousands of nuclei. Prokaryotes such as bacteria, however, have none.
All human cells contain the nucleus except the red blood cells and cornified skin cells.
The Main Functions Of The Nucleus
Now, what is the function of the nucleus? There are several functions associated with the nucleus, but the most important ones are:
The Nucleus Is Where The Largest Percentage Of Deoxyribonucleic Acid (DNA) Is Stored
DNA is our organism’s genetic material passed down from the previous generation. It controls the growth and multiplication of the cells.
DNA has the shape of a double helix with a twisted ladder shape created by strands of nucleotides, and it forms chromatin structurally supported by the nucleoplasm within the nucleus.
A nuclear envelope separates the nucleus from the cytoplasm.
The Nucleus Is The Brain Of The Cell
The nucleus controls all the functions the cell performs, such as growth, metabolism, cell division, and protein synthesis.
As a cell might need to produce a specific protein, the nucleus controls which DNA piece is copied into a ribonucleic acid molecule which then leaves the nucleus and joins the ribosomes (small round organelles) where the proteins are produced.
The nucleus also controls cell metabolism through enzyme synthesis.
The Structure Of The Nucleus
The nucleus consists of four main parts:
1. The Nuclear Envelope
The nuclear envelope separates the nucleus from the rest of the cell contents. It consists of a double membrane separated by perinuclear space. This double membrane consists of phospholipid bilayers, and its pores allow substances to move through it.
They also regulate the passage of RNA (ribonucleic acid) and proteins between the nucleus and the cytoplasm.
2. The Chromatin
The chromatin is formed from the DNA in the nucleus. It contains proteins, mainly histones. Histones prevent the tangling of the DNA and protect it.
The chromatin further forms DNA molecules containing the genetic material of an organism called chromosomes. Humans, for example, have 46 chromosomes grouped into 23 pairs.
3. The Nucleoplasm
The nucleoplasm, also known as the karyoplasm and the nuclear sap, is a substance that contains many proteins, nucleotides that build DNA and RNA, protein-coding genes, and minerals.
The nucleoplasm is found in the cell around the nucleus and it helps to maintain the structure of the nucleus. It is the place of enzyme synthesis.
4. The Nucleolus
The nucleolus is the largest structure within a nucleus and consists of proteins, DNA and RNA. It is where ribosome synthesis takes place.
In addition to that, in recent years, scientific research has shown the significance of nucleoli in the regulation of p53 activation – a nucleus-based protein capable of tumor suppression.
The nucleus is a membrane-encapsulated organelle and an essential part of every eukaryotic cell. It contains the organism’s hereditary material.
It consists of four parts — the nuclear envelope, the chromatin, the nucleoplasm, and the nucleolus.
The main functions of the nucleus are DNA storage, cell growth, metabolism, cell division, and protein synthesis.
Without the nucleus, DNA could not be translated into RNA, and protein synthesis could not happen.