Search results
Results From The WOW.Com Content Network
The cytoplasm contains the cytoskeleton, a network of protein filaments found in all cells, while the nucleoplasm is believed to contain the nuclear matrix, a hypothetically analogous network of filaments that organizes the organelles and genetic information within the nucleus. While the structure and function of the cytoskeleton have been well ...
A typical anther contains four microsporangia. The microsporangia form sacs or pockets (locules) in the anther (anther sacs or pollen sacs). The two separate locules on each side of an anther may fuse into a single locule. Each microsporangium is lined with a nutritive tissue layer called the tapetum and initially contains diploid pollen mother ...
An anucleated cell contains no nucleus and is, therefore, incapable of dividing to produce daughter cells. The best-known anucleated cell is the mammalian red blood cell, or erythrocyte , which also lacks other organelles such as mitochondria, and serves primarily as a transport vessel to ferry oxygen from the lungs to the body's tissues.
An anther and its filament together form a typical (or filantherous) stamen, part of the male floral organ. The typical anther is bilocular, i.e. it consists of two thecae. Each theca contains two microsporangia, also known as pollen sacs. The microsporangia produce the microspores, which for seed plants are known as pollen grains.
Cell nucleus: A cell's information center, the cell nucleus is the most conspicuous organelle found in a eukaryotic cell. It houses the cell's chromosomes , and is the place where almost all DNA replication and RNA synthesis ( transcription ) occur.
Its nucleus is generally haploid, that is, it has half the chromosomes of the plant that gave rise to it. The oosphere fuses with one of the generative nuclei of the pollen grain during double fertilization to give rise to the embryo. The other generative nucleus will fuse with the polar nuclei of the middle cell and give rise to the endosperm.
Cellular compartments in cell biology comprise all of the closed parts within the cytosol of a eukaryotic cell, usually surrounded by a single or double lipid layer membrane. These compartments are often, but not always, defined as membrane-bound organelles. The formation of cellular compartments is called compartmentalization.
The nuclear envelope has many nuclear pores that allow materials to move between the cytosol and the nucleus. [4] Intermediate filament proteins called lamins form a structure called the nuclear lamina on the inner aspect of the inner nuclear membrane and give structural support to the nucleus. [4]