Mitosis Y Meiosis

Páginas: 5 (1027 palabras) Publicado: 13 de abril de 2011

MITOSIS, This process occurs in the nucleus of eukaryotic cells and perform cell division by the equitable distribution of DNA. Makes the process of chromosome segregation and eukaryotic cells, leading to copy the genetic material that makes each new cell gets the same genetic information of the mother cell.
MEIOSIS, is the form of cell reproduction, is produced by the sexglands to rpoducir gametes in this process a diploid cell has successive dicvisiones, by this mechanism will produce eggs and sperm, making two nuclear and cytoplasmic divisions, called meiosis I and meiosis II.

Composed of pentose - deoxyribose, nitrogenous base is a double-stranded chain. In procatiota cell, DNA appears naked and arranged in the cytoplasm.
Function,contains the genetic information of an individual, he moves this information from DNA to RNA, transmitting information between individuals, reports DNA bases, on the order of amino acids and binds this protein form.
Pentose - ribose, nucleobase has its prokaryotic cell is synthesized in the cytoplasm of eukaryotic cells, is synthesized in the cytoplasm to perform itsfunsion.
RNA, is responsible for getting the information from the nucleus of the cytoplasm, making the translation of base sequences in the ribosome.
The RNA, together with proteins forms the ribosomes, the amino acid transports and places them in the order listed to form proteins.

Gregor Johann MENDEL was an Austrian monk and biologist whose work on heredity became the basis of themodern theory of genetics. Mendel was born on July 22, 1822 in Heizendorf, Austria, (now known as Hyncice in Czechoslovakia). He was born Johann Mendel into a poor farming family. At that time it was difficult for poor families to obtain a good education and the young Mendel saw the only way to escape a life of poverty was to enter the monastery at Brunn in Moravis, (now Brno in Czechoslovakia).Here he was given the name Gregor. This monastery was the Augustinian Order of St Thomas, a teaching order with a reputation as a centre of learning and scientific enquiry.
By the 1890's, the invention of better microscopes allowed biologists to discover the basic facts of cell division and sexual reproduction. The focus of genetics research then shifted to understanding what really happens inthe transmission of hereditary traits from parents to children. A number of hypotheses were suggested to explain heredity, but Gregor Mendel , a little known Central European monk, was the only one who got it more or less right. His ideas had been published in 1866 but largely went unrecognized until 1900, which was long after his death. His early adult life was spent in relative obscuritydoing basic genetics research and teaching high school mathematics, physics, and Greek in Brno (now in the Czech Republic). In his later years, he became the abbot of his monastery and put aside his scientific work.
Through the selective cross-breeding of common pea plants (Pisum sativum) over many generations, Mendel discovered that certain traits show up in offspring without any blending ofparent characteristics. For instance, the pea flowers are either purple or white--intermediate colors do not appear in the offspring of cross-pollinated pea plants. Mendel observed seven traits that are easily recognized and apparently only occur in one of two forms:

1. flower color is purple or white 5. seed color is yellow or green
2. flower position is axil or terminal 6. podshape is inflated or constricted
3. stem length is long or short 7. pod color is yellow or green
4. seed shape is round or wrinkled
This observation that these traits do not show up in offspring plants with intermediate forms was critically important because the leading theory in biology at the time was that inherited traits blend from generation to generation. Most of the leading...
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