Mitosis vs Meiosis Differences
Larry H. Bernstein, MD, FCAP, Curator
LPBI
Differences Between Mitosis and Meiosis
http://www.microbiologyinfo.com/differences-between-mitosis-and-meiosis/
Mitosis is a process of asexual reproduction in which the cell divides in two producing a replica, with an equal number of chromosomes in each resulting diploid cell.
Meiosis is a type of cellular reproduction in which the number of chromosomes are reduced by half through the separation of homologous chromosomes, producing two haploid cells.
Following are the differences between Mitosis and Meiosis:
S.N. |
Differences |
Mitosis |
Meiosis |
1 | Type of Reproduction | Asexual | Sexual |
2 | Genetically | Similar | Different |
3 | Crossing Over | No, crossing over cannot occur. | Yes, mixing of chromosomes can occur. |
4 | Number of Divisions | One | Two |
5 | Pairing of Homologs | No | Yes |
6 | Mother Cells | Can be either haploid or diploid | Always diploid |
7 | Number of Daughter Cells produced | 2 diploid cells | 4 haploid cells |
8 | Chromosome Number | Remains the same. | Reduced by half. |
9 | Chromosomes Pairing | Does Not Occur | Takes place during zygotene of prophase I and continue upto metaphase I. |
10 | Creates | Makes everything other than sex cells. | Sex cells only: female egg cells or male sperm cells. |
11 | Takes Place in | Somatic Cells | Germ Cells |
12 | Chiasmata | Absent | Observed during prophase I and metaphase I. |
13 | Spindle Fibres | Disappear completely in telophase. | Do not disappear completely in telophase I. |
14 | Nucleoli | Reappear at telophase | Do not reappear at telophase I. |
15 | Steps | Prophase, Metaphase, Anaphase, Telophase. | (Meiosis 1) Prophase I, Metaphase I, Anaphase I, Telophase I; (Meiosis 2) Prophase II, Metaphase II, Anaphase II and Telophase II. |
16 | Karyokinesis | Occurs in Interphase. | Occurs in Interphase I. |
17 | Cytokinesis | Occurs in Telophase. | Occurs in Telophase I and in Telophase II. |
18 | Centromeres Split | The centromeres split during anaphase. | The centromeres do not separate during anaphase I, but during anaphase II. |
19 | Prophase | Simple | Complicated |
20 | Prophase | Duration of prophase is short, usually of few hours. | Prophase is comparatively longer and may take days. |
21 | Synapsis | No Synapsis | Synapsis of Homologous chromosomes takes place during prophase. |
22 | Exchange of Segments | Two chromatids of a chromosome do not exchange segments during prophase. | Chromatids of two homologous chromosome exchange segments during crossing over. |
23 | Discovered by | Walther Flemming | Oscar Hertwig |
24 | Function | Cellular reproduction and general growth and repair of the body. | Genetic diversity through sexual reproduction. |
25 | Function | Takes part in healing and repair. | Takes part in the formation of gametes and maintenance of chromosome number. |
Differences Between Mitosis and Meiosis
This is very insightful. There is no doubt that there is the bias you refer to. 42 years ago, when I was postdocing in biochemistry/enzymology before completing my residency in pathology, I knew that there were very influential mambers of the faculty, who also had large programs, and attracted exceptional students. My mentor, it was said (although he was a great writer), could draft a project on toilet paper and call the NIH. It can’t be true, but it was a time in our history preceding a great explosion. It is bizarre for me to read now about eNOS and iNOS, and about CaMKII-á, â, ã, ä – isoenzymes. They were overlooked during the search for the genome, so intermediary metabolism took a back seat. But the work on protein conformation, and on the mechanism of action of enzymes and ligand and coenzyme was just out there, and became more important with the research on signaling pathways. The work on the mechanism of pyridine nucleotide isoenzymes preceded the work by Burton Sobel on the MB isoenzyme in heart. The Vietnam War cut into the funding, and it has actually declined linearly since.
A few years later, I was an Associate Professor at a new Medical School and I submitted a proposal that was reviewed by the Chairman of Pharmacology, who was a former Director of NSF. He thought it was good enough. I was a pathologist and it went to a Biochemistry Review Committee. It was approved, but not funded. The verdict was that I would not be able to carry out the studies needed, and they would have approached it differently. A thousand young investigators are out there now with similar letters. I was told that the Department Chairmen have to build up their faculty. It’s harder now than then. So I filed for and received 3 patents based on my work at the suggestion of my brother-in-law. When I took it to Boehringer-Mannheim, they were actually clueless.