does the cell theory state that cell come from cells that already exist?
Yes, according to the cell theory, cells arise from pre-existing cells. This principle is a fundamental concept in biology and was first proposed by Matthias Schleiden and Theodor Schwann in the 19th century. The cell theory comprises three main principles:
1. All living organisms are composed of one or more cells.
2. The cell is the basic unit of structure, function, and organization in all living organisms.
3. Cells arise from pre-existing cells through the process of cell division.
To understand why cells come from pre-existing cells, it is essential to consider the process of cell division. There are two main types of cell division: mitosis and meiosis. In mitosis, one cell divides into two identical daughter cells, while in meiosis, specialized cells called gametes are formed for sexual reproduction.
During both mitosis and meiosis, the original cell undergoes a precise series of events, such as DNA replication, chromosome segregation, and cytokinesis, resulting in the formation of new cells. These new cells inherit genetic material and cellular components from their parent cells, ensuring continuity and preservation of genetic information.
Experimental observations and advancements in microscopy have played a crucial role in supporting the cell theory. Scientists have observed cells dividing under a microscope, providing visual evidence that cells arise from pre-existing cells.
In summary, the cell theory states that cells come from cells that already exist, and this concept is supported by extensive experimental evidence and observation of cell division processes.