What are Some Differences Between Plant and Animal Cells?

Plant cells are the basic unit of the structure and function of plant life activities. They consist of protoplasts and cell walls. Protoplasts are the general term for all substances in the cell wall. They are mainly composed of cytoplasm and nucleus. There are several different organelles in the cytoplasm or nucleus, in addition to the cytosol and post inclusions.

Robert Hooke, Royal Academy of Sciences

The cytoplasm of typical plant cells can be divided into membranes (

The growth and reproduction of plant individuals are the result of an increase in the number of cells, an increase in the volume of each cell, and functional differentiation. The increase in the number of cells is achieved through cell division, which is one of the characteristics of life. There are three main types of cell division: mitosis, amitosis, and meiosis.

Plant cell mitosis

Mitosis is one of the most common forms of division, which occurs mainly in cells at the root tip, stem tip, and young parts of fast-growing plants. In the past, more attention was paid to studying the morphological changes of the mitotic stage during mitosis, and there was little discussion of the interval. In fact, the interphase is very important, and both nucleic acid and protein synthesis occur during this period. Therefore, mitosis must be elucidated from the entire cell cycle. From one cell division

The process from the onset of fission to the next division is called the cell cycle (Figure 1-30), that is, the cell cycle includes an interphase and a mitosis. Plant cell cycle elapsed time generally ranges from a dozen to tens of hours. The DNA content and growth conditions in the cell can affect the length of time. The cell cycle is the longest in the S phase and the shortest in the M phase.

G1 and G: The period length varies greatly (Table 1-1). ^[4]

Plant cell mitosis

Mitosis is also called direct division (direct dlision). The division process is relatively simple. During division, there are no complicated changes such as chromosomes in the nucleus. There are many forms of mitosis, the most common of which is the transverse seam, that is, the nucleus is first extended, then shrinks and thins in the middle, and finally breaks into two daughter nuclei. In addition, there are many forms of longitudinal seam, budding, chipping and so on. Moreover, different forms of division can occur within the same organization. In the past, mitosis was thought to be more common in lower plants, and only senescent and diseased cells were found in higher plants. However, it is now found that mitosis is also more common in higher plants. For example, the development of endosperm and the formation of callus and adventitious roots often occur frequently; even in some normal tissues, such as thin-walled tissue, epidermis, apical meristem, anther tapetum cells, etc. , Also happened. Compared with mitosis, mitosis has a simpler process, so it consumes less energy and is faster, but the material in the nucleus is not evenly distributed to the daughter nuclei, which involves genetic stability. The biological significance of mitosis needs to be further studied.

Plant cell meiosis

Meiosis is a division related to the formation of germ cells or sex cells. Higher plants must undergo meiosis when large and small spores form. The entire process of meiosis includes two consecutive divisions, namely the first meiotic division (referred to as division I) and the second meiotic division (referred to as division ). As a result, four daughter cells are formed, and the number of chromosomes in the nucleus of each daughter cell is formed. It is half the number of chromosomes in the mother cell, so it is called meiosis. ^[5]