2025年12月10日 · What is a cell? A cell is a mass of cytoplasm that is bound externally by a cell membrane. Usually microscopic in size, cells are the smallest structural units of living matter …

5 日前 · Meiosis, division of a germ cell involving two fissions of the nucleus and giving rise to four gametes, or sex cells, each with half the number of chromosomes of the original cell.

2025年12月5日 · A plant cell is the basic unit of all plants. Plant cells, like animal cells, are eukaryotic, meaning they have a membrane-bound nucleus and organelles. Their characteristic …

2025年12月10日 · Cell - Structure, Organelles, Metabolism: Like the cell membrane, membranes of some organelles contain transport proteins, or permeases, that allow chemical …

2025年12月29日 · Chloroplast, structure within the cells of plants and green algae that is the site of photosynthesis. Chloroplasts are a type of plastid that are distinguished by their green color, …

2025年12月16日 · Lysosome, subcellular organelle that is found in nearly all types of eukaryotic cells and that is responsible for the digestion of macromolecules, old cell parts, and …

2025年12月28日 · Mitosis is a process of cell duplication, in which one cell divides into two genetically identical daughter cells. In the various stages of mitosis, the cell’s chromosomes …

2026年1月5日 · Mitochondria are typically round to oval in shape and range in size from 0.5 to 10 μm. In addition to producing energy, mitochondria store calcium for cell signaling activities, …

2025年12月10日 · This array of proteins, sterols, and phospholipids is organized into a liquid crystal, a structure that lends itself readily to rapid cell growth. Measurements of the …

The chemical structure of the cell membrane makes it remarkably flexible, the ideal boundary for rapidly growing and dividing cells. Yet the membrane is also a formidable barrier, allowing …