Cell growth and reproduction is guided by the genetic code present in the DNA strands of the cell. These DNA strands form genes, which are packaged in chromosomesContinue Reading
Reproduction can be either sexual or asexual. In asexual reproduction, a single set of genetic information is replicated in an identical cell. The first step is the copying of a second set of chromosomes identical to the first in the cell nucleus. These two set then latch onto opposing sides of the cell. The cell membrane on these opposing sides continues to constrict until the cell is cleaved down the middle. This method of reproduction produces an offspring that is a perfect clone of the organism. It is the only means of reproduction in single-celled organisms. Some multicellular organisms, such as starfish, can also reproduce this way.
Sexual reproduction results from the joining of two specialized reproductive cells, such as sperm and ova. The advantage of this form of reproduction is that it introduces a larger pool of genetic diversity, as the offspring has two sets of DNA instead of the single set that is copied in asexual reproduction. Reproduction through sexual means involves the cells undergoing a complex replication and division process called mitosis.Learn more about Cells
Cell theory was developed in the early 19th century by three German scientists, Theodor Schwann, Matthias Jacob Schleiden and Rudolf Virchow. While all three scientists contributed to the generally accepted classical cell theory, each hypothesized different sections of it and had parts of their theory refuted and replaced.Full Answer >
Cell division is limited by a process called cellular senescence, during which cells in culture divide more slowly before stopping entirely. The cells do not necessarily die during senescence, but they no longer replicate.Full Answer >
Cell division is part of the cell cycle, and it is caused either by binary fission or as part of a multiple-phase cycle. Binary fission is the method by which prokaryotic cells divide. Eukaryotic cells use the three-phase cycle commonly referred to as mitosis.Full Answer >
Cell walls are located around the plasma membranes of certain types of cells. Cell membranes protect the cell, but cell walls have many extra functions, including providing an extra layer of protection and giving cells a more rigid structure.Full Answer >