During prophase I, each of the homologous pairs of chromosomes can be seen as bivalent or as a grouping of two chromosomes said to be sister chromatids. The site at which the crossing over occurs on the sister chromatids is known as the chiasma. Prophase I is the longest phase during the meiosis process and takes up to 90 percent of the total time of cell division.
Castor beans are pressed to extract castor oil which is used for medicinal purposes. Ricin (a toxic substance present in the plant) does not partition into the oil because it is water-soluble, therefore, castor oil does not contain ricin, provided that no cross-contamination occurred during its production.icin (a toxic substance present in the plant) does not partition into the oil because it is water-soluble, therefore, castor oil does not contain ricin, provided that no cross-contamination occurred during its production.
Toxic principle. The principle toxin of castor bean is ricin which is a lectin, also termed a toxalbumin. Ricin may comprise up to 3% of the seed weight. Toxalbumins are very toxic plant-derived compounds that combine carbohydrate and protein moieties or components.Ricin is water soluble and is not present in castor oil. Taken orally, ricin is readily absorbed from the stomach and intestine.onditions of poisoning. All parts of the plants are toxic, but most dangerous are the seeds. The most susceptible animal species include cattle, horses, sheep, pigs, fowl, rabbits and other small animals.