Judy Taylor
[lwptoc]
Introduction: Plants and animals, same cells?
Plants and animals are two distinct types of organisms with unique characteristics, but both share a fundamental unit of life: the cell. Although plant and animal cells have many similarities, such as the presence of a nucleus and numerous organelles, there are also notable differences between them. One of the most significant differences in cell behavior between plants and animals is how they undergo cell division.
Cleavage furrows and cell division in animal cells
In animal cells, cell division occurs through a process called mitosis. During mitosis, the cell undergoes several phases, including prophase, metaphase, anaphase, and telophase. One of the most prominent features of mitosis in animal cells is the formation of cleavage furrows during cytokinesis. The cleavage furrow is a contractile ring of microfilaments that forms around the cell’s equator, causing the cell to pinch in the middle and eventually split into two daughter cells.
Cell division in plant cells
Plant cells also undergo cell division through a process called cytokinesis, but the process is markedly different from that of animal cells. Instead of forming a cleavage furrow, plant cells form a cell plate that grows outward from the center of the dividing cell. The cell plate eventually fuses with the cell membrane, separating the two daughter cells. The process of cytokinesis in plant cells is complex and involves numerous components, including the cell wall, cytoskeleton, and phragmoplast.
Differences in cell division between plants and animals
The differences in the way plant and animal cells divide can be attributed to several factors. One of the most significant differences is the presence of a cell wall in plant cells, which animal cells lack. The cell wall provides rigidity and support to the cell, allowing it to resist the force generated by the contracting cleavage furrow. Additionally, plant cells have a more rigid cytoskeleton than animal cells, which helps maintain the cell’s shape during cell division.
The cell wall and its role in plant cell division
The cell wall plays a crucial role in plant cell division. During cytokinesis, the cell plate is formed from vesicles that originate from the Golgi apparatus. These vesicles contain cellulose and other components that make up the cell wall. As the cell plate grows outward from the center of the dividing cell, it fuses with the existing cell wall, forming a complete cell wall that separates the two daughter cells.
The role of the cytoskeleton in plant cells
The cytoskeleton in plant cells is composed of microtubules and microfilaments, which help maintain the cell’s shape and provide structural support during cell division. Unlike animal cells, plant cells have a more rigid cytoskeleton, which allows them to resist the force generated during cytokinesis. Additionally, the cytoskeleton plays a crucial role in the formation of the phragmoplast.
The role of the phragmoplast in plant cell division
The phragmoplast is a structure that forms during cytokinesis in plant cells. It is composed of microtubules and microfilaments and is responsible for guiding the formation of the cell plate. The phragmoplast grows outward from the center of the dividing cell, pushing the cell plate toward the cell membrane.
The absence of centrioles in plant cells
Centrioles are small, cylindrical structures that are involved in organizing the microtubules during cell division in animal cells. However, plant cells do not have centrioles, but they do have microtubule organizing centers that play a similar role.
The role of plant hormones in cell division
Plant hormones, such as auxins and cytokinins, play an essential role in promoting cell division in plants. Auxins promote cell division by stimulating the production of proteins that are involved in cell division, while cytokinins promote cell division by activating cell cycle regulators.
Conclusion: Plants and animals, different strategies for cell division
In conclusion, plant and animal cells have evolved different strategies for cell division. Although the fundamental process of cytokinesis is the same, the mechanisms used to achieve it differ significantly between the two types of cells. The presence of a cell wall, a more rigid cytoskeleton, the formation of a cell plate, and the absence of centrioles are some of the key factors that contribute to the differences in cell division between plants and animals.
