Difference Between Cytoplasm and Cytoskeleton

Main Difference – Cytoplasm vs Cytoskeleton

Cytoplasm and cytoskeleton are two structural components of the cell. The cell is considered as the smallest structural and functional unit of life. It is composed of a fluid that is surrounded by a selective membrane and suspends various organelles as well as molecules. All structural components, as well as molecules, are related to the functioning of the cell. The main difference between cytoplasm and cytoskeleton is that cytoplasm is the thick, jelly-like fluid in which the cellular components are embedded in whereas cytoskeleton is a network of protein filaments and tubules in the cytoplasm. Cytoplasm is present in both prokaryotes and eukaryotes whereas cytoskeleton is only present in eukaryotes.

Key Areas Covered

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

Key Terms: Crowding, Cytoplasm, Cytoplasmic Streaming, Cytoskeleton, Cytosol, Inclusions, Intermediate Filaments, Microfilaments, Microtubules, Organelles

What is Cytoplasm

Cytoplasm refers to the cell substance between the cell membrane and the nucleus, containing cytosol, organelles, cytoskeleton, and various particles. Both prokaryotes and eukaryotes contain a cytoplasm. The inner area of the cytoplasm is called the endoplasm whereas the outer area of the cytoplasm is called the cell cortex or the ectoplasm. Endoplasm is more concentrated than ectoplasm. The cellular components embedded in the cytoplasm are shown in figure 1.

Figure 1: Cytoplasm and Cellular Components

Cytoplasm is usually a colorless fluid, and 80% of it is composed of water. It is enclosed by the cell membrane. Cytosol is the gel-like component of the cytoplasm in which all cellular components are embedded in. Organelles are the membrane-bound functional structures of the cell, which are only present in eukaryotic cells. Organelles in the cytoplasm include the nucleus, mitochondria, Golgi apparatus, endoplasmic reticulum, lysosomes. Most of the biochemical reactions take place in the cytoplasm in prokaryotes as they lack organelles. Some biochemical reactions take place in the cytoplasm of eukaryotes as well.

The main function of cytoplasm is to suspend organelles. It provides a preferred chemical environment for the occurrence of biochemical reactions by storing different types of macromolecules in it. These macromolecules and other functional molecules in the cytoplasm are called the inclusions. The concentration of macromolecules may differ in different areas of the cytoplasm. This is called crowding. The cytoplasmic movements of the plant cells are called cytoplasmic streaming.

What is Cytoskeleton

Cytoskeleton refers to a microscopic network of protein filaments and microtubules in the cytoplasm of a living cell. Microtubules, intermediate filaments, and microfilaments are the components of the cytoskeleton. Microfilaments are the thinnest fibers, and the microtubules are the thickest fibers in the cytoskeleton. The three components of the cytoplasm are shown in figure 2.

Figure 2: Components of Cytoskeleton
(a)Microtubules, (b) Microfilaments, (c) Intermediate Filaments

Microtubules facilitate the movements of organelles and vesicles inside the cytoplasm. They also form the mitotic spindle during the cell division. Both microfilaments and intermediate filaments maintain the shape of the cell. The cytoskeleton is also composed of motor proteins, which actively move fibers in the cytoskeleton. The motor proteins are powered by ATP. The three types of motor proteins in the cytoskeleton are kinesins, dyneins, and myosins.

The main function of the cytoskeleton is to maintain the shape of the cell. Various organelles in the cell are held by the cytoskeleton in their relevant positions inside the cytoplasm. The cytoskeleton facilitates the formation of vacuoles. It is a dynamic structure which enables the internal and external movements of the cell. The transportation of cell signals inside the cell is also facilitated by the cytoskeleton. The cytoskeleton forms cellular protrusions such as cilia and flagella.

Similarities Between Cytoplasm and Cytoskeleton

• Both cytoplasm and cytoskeleton are two components of the cell.
• Both cytoplasm and cytoskeleton occur in eukaryotes.

Difference Between Cytoplasm and Cytoskeleton

Definition

Cytoplasm: Cytoplasm refers to the cell substances between the cell membrane and the nucleus, containing the cytosol, organelles, cytoskeleton, and various particles.

Cytoskeleton: Cytoskeleton refers to a microscopic network of protein filaments and microtubules in the cytoplasm of a living cell.

Significance

Cytoplasm: Cytoplasm is a fluid in which all the other cellular components are embedded in.

Cytoskeleton: Cytoskeleton is made up of protein filaments and microtubules.

Components

Cytoplasm: Cytoplasm is composed of cytosol, organelles, and inclusions.

Cytoskeleton: Cytoskeleton is composed of microtubules, microfilaments, and intermediate filaments.

Occurrence

Cytoplasm: Cytoplasm is present in both prokaryotes and eukaryotes.

Cytoskeleton: Cytoskeleton is present only in eukaryotes.

Function

Cytoplasm: Cytoplasm suspends organelles, provides sites for biochemical reactions and helps to maintain the shape of the cell.

Cytoskeleton: Cytoskeleton helps the movement of organelles and vesicles and helps to maintain the shape of the cell.

Conclusion

Cytoplasm and cytoskeleton are two components of the cell. Cytoplasm is a fluid composed of cytosol, organelles, cytoskeleton, and inclusions. Cytoskeleton is composed of microtubules, microfilaments, and intermediate filaments. Cytoplasm provides a defined medium for the occurrence of biochemical reactions of the cell. Cytoskeleton maintains the movements inside the cell while maintaining the cell shape. The main difference between cytoplasm and cytoskeleton is the structure and the function of each component inside the cell.

Reference:

1. “Cytoplasm.” [email protected], Available here.
2. “The cytoskeleton.” Khan Academy, Available here.

Image Courtesy:

1. “0312 Animal Cell and Components” By OpenStax –  (CC BY 4.0) via Commons Wikimedia
2. “0317 Cytoskeletal Components” By OpenStax – (CC BY 4.0) via Commons Wikimedia

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