What is the Difference Between Cytoplasm and Nucleus

The main difference between cytoplasm and nucleus is that cytoplasm is the contents inside the cell excluding the nucleus whereas nucleus is the largest organelle of the cell containing genetic material. Furthermore, the cytoplasm is surrounded by the plasma membrane whereas the nucleus is surrounded by the nuclear membrane.

Cytoplasm and nucleus are two structural components of the cell. They perform vital functions inside the cell.

Key Areas Covered

1. What is the Cytoplasm
      – Definition, Structure, Function
2. What is the Nucleus
      – Definition, Structure, Function
3. What are the Similarities Between Cytoplasm and Nucleus
      – Outline of Common Features
4. What is the Difference Between Cytoplasm and Nucleus
      – Comparison of Key Differences

Key Terms

Cytoplasm, Eukaryotes, Genetic Material, Nucleus, Organelles

What is the Cytoplasm

The cytoplasm is the materials between the plasma membrane and the nuclear membrane. It includes the cytosol, cell organelles, and cytoplasmic inclusions. Here, the cytosol is a gel-like substance in which many of the metabolic reactions of the cell take place. Whereas, cell organelles are internal sub-structures which perform unique functions. On the other hand, cytoplasmic inclusions are materials that do not involve in metabolic activities. Usually, the cytoplasm is colorless and is composed of 90% of water.

Figure 1: Cytoplasm of an Animal Cell

Furthermore, the concentrated inner area of the cytoplasm is known as the endoplasm while the outer layer is known as the ectoplasm or cell cortex. More importantly, most of the cellular activities occur inside the cytoplasm. For example, in prokaryotes, all the metabolic reactions including glycolysis, fermentation, etc. occur inside the cytoplasm. However, in eukaryotes, some biochemical reactions including glycolysis occur in the cytoplasm. Besides, the cytoplasm undergoes cellular processes such as cell division.

What is the Nucleus

The nucleus is the most prominent organelle of the eukaryotic cell, containing genetic material. Euchromatin and heterochromatin are the two main types of chromatin found inside the nucleus. The nucleus is surrounded by the nuclear membrane, which is a double-membrane system. Perinuclear space refers to the space between the outer and inner nuclear membrane. It is 20-40 nm wide. Also, the outer nuclear membrane is continuous with the endoplasmic reticulum. Furthermore, intermediate filaments form a lamina internally to the inner nuclear membrane and externally to the outer nuclear membrane, providing structural support to the nucleus. Additionally, nuclear pores are the aqueous pores that occur in the nuclear membrane, allowing the passage of molecules in and out of the nucleus.

Figure 2: Nucleus

Describing further, the nuclear matrix refers to the isolated matrix of the nucleus. The dark-staining mass of the nucleus visible under the light microscope is the nucleolus. It is responsible for manufacturing ribosomal RNA. Besides, the main function of the nucleus is to facilitate gene expression. Therefore, DNA replication, transcription, and ribosome biogenesis occur inside the nucleus. Moreover, the nucleus is responsible for maintaining the integrity of genes. However, the genetic material of prokaryotes occurs in the nucleoid, which is an area of the cytoplasm.

Similarities Between Cytoplasm and Nucleus

• Cytoplasm and nucleus are two structural components of a eukaryotic cell.
• The cell membrane surrounds both structures.
• Therefore, they maintain a unique environment, facilitating their function.
• Also, a number of vital cellular processes occur inside these structures.

Difference Between Cytoplasm and Nucleus

Definition

Cytoplasm refers to the material or protoplasm within a living cell, excluding the nucleus, while nucleus refers to a dense organelle present in most eukaryotic cells, typically a single rounded structure bounded by a double membrane, containing the genetic material. Thus, this is the main difference between cytoplasm and nucleus.

Occurrence

While cytoplasm occurs in all living organisms, many eukaryotic cells have a nucleus.

Significance

Also, another difference between cytoplasm and nucleus is that cytoplasm is a fluid-filled compartment while nucleus is the control center of the cell.

Composition

Moreover, the cytoplasm includes the cytosol, organelles excluding the nucleus, vesicles, and the cytoskeleton while the nucleus contains DNA, RNA, and proteins. Hence, this is also a difference between cytoplasm and nucleus.

Cell Membranes

Furthermore, cell membranes are another difference between cytoplasm and nucleus. Cytoplasm occurs between the plasma membrane and nuclear membrane while the nucleus is surrounded by the nuclear membrane.

Significance of the Membrane System

Besides, the cytoplasm is surrounded by a single membrane system while the nucleus is surrounded by a double membrane system.

Structural support

Additionally, the cytoskeleton provides the structural support to the cytoplasm while nuclear lamina provides the structural support to the nucleus.

Function

Functionally, the difference between cytoplasm and nucleusis that the cytoplasm facilitates the occurrence of a number of cellular activities including cell division and metabolic pathways while the nucleus contains the genome and facilitates gene expression.

Conclusion

The cytoplasm is the fluid-filled content of the cell surrounded by the plasma membrane. However, it does not include the nucleus, which is the most prominent organelle of a eukaryotic cell. Therefore, the cytosol, cell organelles, and cell inclusions are the components of the cytoplasm. Also, the main function of the cytoplasm is to facilitate cellular activities. On the other hand, the nucleus bears the genome and it is surrounded by the nuclear membrane. In addition, the nucleus allows the expression of genes. Hence, the main difference between cytoplasm and nucleus is their structure and function.

References:

1. “The Nucleus and Cytoplasm.” Lumen|Anatomy and Physiology, Available Here.

Image Courtesy:

1. “0312 Animal Cell and Components” By OpenStax (CC BY 4.0) via Commons Wikimedia   
2. “Diagram human cell nucleus” By Mariana Ruiz LadyofHats (Public Domain) via Commons Wikimedia