Cytology is the study life at the cellular level, another name for this discipline is cell biology. Plant cells share many features with animal cells. Both forms of life are composed of eukaryotic cells, which have a distinct nucleus surrounded by a nuclear envelope which separates it from the cytoplasm. (By contrast, bacteria have nucleus-free cells, called prokaryotic cells.) Inside the nucleus is chromatin, which becomes organized into chromosomes as a cell divides. Chromosomes are composed of functional units called genes, which serve as the control center of the cell. Genes are composed of nucleoprotein. The nucleus also contains a nucleolus. The cytoplasm is differentiated into nu particular activity. Among those which plant cells share with animal cells are mitochondria (which conduct cellular respiration), ribosome’s (which conduct protein synthesis), endoplasmic reticulum, Golgi apparatus , and a plasma membrane (which functions as the cell's outer boundary). Not found in animal cells are chloroplasts (which conduct photosynthesis). Surrounding each plant cell are several layers of compounds (especially cellulose) that form the cell wall.
See also: Ecology, Molecular Biology, Genetics, Physiology
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