Opened double. Who discovered the double helix of DNA? See what “Double fertilization” is in other dictionaries
Ending. See No. 20, 21, 22/2002
Biology lessons in 10th (11th) grade
Appendix 1. Codogram for lesson 6
Topic: “Theme “Ontogenesis” (§ 21)Ontogenesis: embryogenesis + postembryonic development. Stages of embryogenesis 1. Fertilization After penetration into the egg, the tail and neck of the sperm are destroyed, the DNA is doubled, the pronuclei merge, 1n2c + 1n2c = 2n4c. 2.Crushing, blastulation. All drawings are at home! Zygote --> blastomeres --> morula --> blastula
The primary cavity is the blastocoel ( 2 ), blastoderm ( 1 ).
Echinoderms and chordates are deuterostomes.
4.Neurulation(the neural plate closes into the neural tube): 1 – ectoderm; 2 – endoderm; 3 – mesoderm; 4 – neural plate; 5 – chord. (Induction - Spemann's experiments.) 5.Organogenesis
Endoderm: digestive and respiratory systems. Mesoderm: skeleton, muscles, circulatory, excretory and reproductive systems. Postembryonic development Direct - no larval stage: spiders, cartilaginous fish, reptiles, birds, mammals. |
3.Gastrulation. In the gastrula there are: 1
– ectoderm; 2
– endoderm; 3
– blastopore (primary mouth); 4
- gastrocele.
Ectoderm: NS, sensory organs, skin epidermis and its derivatives.Appendix 2. Card for working at the board
Appendix 3. Computer testing
"Double fertilization of flowering plants"
Test 1. How many ovules can there be in a pistil?
1. Always alone.
2. Usually equal to the number of seeds.
3. Usually equal to the number of fruits.
4. Equal to the number of pistils.
Test 2. A flower is an organ of asexual and sexual reproduction. What is asexual reproduction?
1. In the formation of seeds.
2. In the formation of fruits.
3. There is a dispute in education.
4. In the formation of gametes.
Test 3. What parts of the flower form the perianth?
1. A calyx made of sepals.
2. Corolla of petals.
3. Calyx and corolla.
4. Calyx, corolla, androecium and gynoecium.
Test 4. What is the male gametophyte of flowering plants?
1. A set of stamens.
2. Pollen sac.
3. Microspore.
4. Pollen grain.
Test 5. What is the female gametophyte of flowering plants?
1. Pestle.
2. Ovary of the pistil.
3. Ovule.
4. Embryonic sac.
Test 6. What is formed from a fertilized egg?
1. Seed.
2. Fruit.
3. Seed embryo.
4. Endosperm.
Test 7. What is formed from the fertilized central cell?
1. Fruit.
2. Seed.
3. Seed embryo.
4. Endosperm.
Test 8. What is formed from integuments?
1. Pericarp.
2. Seed coat.
3. Endosperm.
4. Cotyledons.
Test 9. What is the pericarp formed from?
1. From integuments.
2. From the walls of the ovary.
3. From a pestle.
4. From the receptacle.
Test 10. Who discovered double fertilization?
1. S.G. Navashin.
2. I.V. Michurin.
3. N.I. Vavilov.
4. G. Mendel.
Lesson 7. Test for the section “Reproduction and Development”
Tasks: summarize factual material from a general biological and evolutionary perspective, check the assimilation of specific factual material, deepen and expand students’ knowledge.
Demo material: films, student reports, newspapers, newsletters.
DURING THE CLASSES
Repetition. Written test (30 min).
Tests and test questions are posted a week in advance. Topics for essays and newspapers are offered.
The test will include the same tests and questions, but in a different order. The teacher distributes sheets of questions to each table, the class is divided into two options, each option is offered 10 tests (1–10, 11–20, 21–30, 31–40) and one theoretical question. The next class will have other tests and other theory questions.
Questions for testing
Option 1
1. What is the name of the set of chromosomes characteristic of a species?
2. What is the set of chromosomes in somatic and germ cells?
3. How many chromosomes and DNA are there in different periods of interphase?
4. What are the paired, identical chromosomes of a somatic cell called?
5. What are the names of the primary constriction and the ends of the chromosome?
6. How many chromosomes and DNA are there in a cell before mitosis and at the end of mitosis?
7. How many chromosomes and DNA are there in prophase, metaphase and anaphase of mitosis?
8. What is the meaning of meiosis?
9. What are the names of the first and second divisions of meiosis?
10. What processes occur in the cell during prophase I of meiosis?
11. How many chromosomes and DNA are there before meiosis, after the first and second divisions?
12. What is the set of chromosomes and DNA in metaphase I and anaphase I of meiosis?
15. When does recombination of genetic material occur in meiosis?
16. List the phases of meiosis during which the chromosomes are bichromatid.
18. What is the name of the division in which multiple divisions of the nucleus occur and several individuals are formed (in trypanosomes, malarial plasmodium)?
19. What is characteristic of the genotypes of daughter individuals compared to the mother during asexual reproduction?
20. What set of chromosomes do spores have?
21. What are the membranes of the mammalian egg called?
22. When does oogenesis begin in humans?
23. What is the name of reproduction, in which the development of a new organism occurs from an unfertilized egg?
24. What is the set of chromosomes of gametogonies, 1st order gametocytes, 2nd order gametocytes?
25. What is formed after spermatogenesis from one spermatocyte?
26. What is formed after oogenesis from one oocyte?
27. Which organisms have external fertilization?
28. What are the male and female gametophytes of flowering plants?
29. What is formed from the integuments and the central cell of the embryo sac?
30. What is the pericarp formed from?
31. Who discovered double fertilization?
32. What periods does the ontogeny of animals consist of?
33. What periods does animal embryogenesis consist of?
34. What is formed as a result of fragmentation of the zygote?
35. What is the name of the two-layer lancelet embryo?
36. What is formed from the ectoderm, endoderm and mesoderm of the neurula?
37. From which germ layers do the spine, epidermis and lungs form?
38. What animals are deuterostomes?
39. Name three animals with direct postembryonic development.
40. Name three animals with indirect postembryonic development.
Theoretical issues
1. Mitotic cell cycle.
2. Draw and explain the behavior of a pair of homologous chromosomes during prophase, metaphase, anaphase and telophase of the first meiotic division.
Option 2
1. What is formed after spermatogenesis from one spermatocyte?
2. What animals are deuterostomes?
3. What is formed from the integuments and the central cell of the embryo sac?
4. What is the name of the set of chromosomes characteristic of a species?
5. How many chromosomes and DNA are there in different periods of interphase?
6. How many chromosomes and DNA are there in prophase, metaphase and anaphase of mitosis?
7. What is the name of the two-layer lancelet embryo?
8. What is the meaning of meiosis?
9. What processes occur in the cell during prophase I of meiosis?
10. How many chromosomes and DNA are there before meiosis, after the first and second division?
11. What is the set of chromosomes and DNA in metaphase I and anaphase I of meiosis?
12. What is the pericarp formed from?
13. What is characteristic of the interphase between the first and second divisions of meiosis?
14. What is the set of chromosomes and DNA in metaphase II and anaphase II of meiosis?
15. What is formed after oogenesis from one oocyte?
16. What are the paired, identical chromosomes of a somatic cell called?
17. What is characteristic of asexual reproduction?
18. What periods does animal embryogenesis consist of?
19. How many chromosomes and DNA are there in a cell before mitosis and at the end of mitosis?
20. What is the name of the division in which multiple divisions of the nucleus occur and several individuals are formed (in trypanosomes, malarial plasmodium)?
21. What is characteristic of the genotypes of daughter individuals compared to the mother during asexual reproduction?
22. From which germ layers do the spine, epidermis and lungs form?
23. What set of chromosomes do spores have?
24. What are the membranes of the mammalian egg called?
25. What are the primary constriction and ends of the chromosome called?
26. When does oogenesis begin in humans?
27. Name three animals with indirect postembryonic development.
28. What is the name of reproduction, in which the development of a new organism occurs from an unfertilized egg?
29. What is the set of chromosomes of gametogonies, 1st order gametocytes, 2nd order gametocytes?
30. What is the set of chromosomes in somatic and germ cells?
31. Which organisms have external fertilization?
32. What are the male and female gametophytes of flowering plants?
33. Who discovered double fertilization?
34. What periods does the ontogeny of animals consist of?
35. List the phases of meiosis during which the chromosomes are bichromatid.
36. What is formed as a result of fragmentation of the zygote?
37. What are the first and second divisions of meiosis called?
38. What is formed from the ectoderm, endoderm and mesoderm of the neurula?
39. When does recombination of genetic material occur in meiosis?
40. Name three animals with direct postembryonic development.
Theoretical issues
1. Mitotic cell cycle.
2. Draw and explain the behavior of a pair of homologous chromosomes during prophase, metaphase, anaphase and telophase of the first meiotic division.
3. Asexual reproduction and its forms.
4. Eggs, sperm. Gametogenesis.
5. Types of ontogenesis. Stages of embryogenesis.
6. Formation of spores and gametes in flowering plants. Double fertilization.
Watching films, listening to abstracts in order to deepen knowledge on this section (10 min).
Topics for abstracts:“Natural and artificial parthenogenesis”, “Cloning”, “Hermaphroditism”, “The role of hormones in the life of organisms”, “Aging and immortality”.
Answers to assignments
Assignment on the topic “Mitosis”. Test 1. 2. Test 2. 1. Test 3. 3. Test 4. 2. Test 5. 2. Test 6. 3. *Test 7. 1, 2. Test 8. 3. Test 9. 3. *Test 10. 2, 3, 4, 5.
Assignment on the topic “Meiosis”. Test 1. 1. Test 2. 2. Test 3. 1. *Test 4. 1, 2, 3. Test 5. 7. *Test 6. 4, 5, 6. Test 7. 8, Test 8. 8. *Test 9. 1, 3, 7. Test 10. 1.
Assignment on the topic “Asexual and sexual reproduction.” Test 1. 8. Test 2. 4. Test 3. 6. Test 4. 7. Test 5. 3. *Test 6. 1, 3. Test 7. 2. *Test 8. 2, 3, 4. *Test 9. 1, 2, 3. Test 10. 4.
Assignment on the topic “Gametogenesis. Fertilization". Test 1. 1. Test 2. 3. Test 3. 4. Test 4. 1. Test 5. 4. Test 6. 1. Test 7. 3. Test 8. 2. *Test 9. 1, 2. *Test 10. 1, 2, 3.
Assignment on the topic “Double fertilization of flowering plants.” Test 1. 2. Test 2. 3. Test 3. 3. Test 4. 1. Test 5. 4. Test 6. 3. Test 7. 4. Test 8. 2. Test 9. 2. Test 10. 1.
Discovery of the DNA double helix
Nucleic acids were first discovered in the nucleus of human cells by the Swiss researcher Friedrich Miescher in 1869. At the beginning of the 20th century, biologists and biochemists managed to elucidate the structure and basic properties of the cell. It has been discovered that one of the nucleic acids, DNA, is an extremely large molecule made up of structural units called nucleotides, each containing nitrogenous bases.
Maurice Wilkins and Rosalyn Franklin, scientists from the University of Cambridge, carried out X-ray structural analysis of DNA molecules and showed that they are a double helix, reminiscent of a spiral staircase. The data they obtained led the American biochemist James Watson to the idea of studying the chemical structure of nucleic acids. The National Society for the Study of Infantile Paralysis provided a grant. In October 1951, at the Cavendish Laboratory at the University of Cambridge, Watson began studying the spatial structure of DNA together with John C. Kendrew and Francis Crick, a physicist who was interested in biology and was writing his doctoral dissertation at the time.
DNA helix
Watson and Crick knew that there are two types of nucleic acids - deoxyribonucleic acid (DNA) and ribonucleic acid (RNA), each of which consists of a pentose monosaccharide, phosphate and four nitrogenous bases: adenine, thymine (in RNA - uracil), guanine and cytosine. Over the next eight months, Watson and Crick combined their results with those already available and, in February 1953, reported on the structure of DNA. A month later, they created a three-dimensional model of the DNA molecule, made from beads, pieces of cardboard and wire.
According to the Crick–Watson model, DNA is a double helix consisting of two chains of deoxyribose phosphate connected by base pairs similar to the rungs of a ladder. Through hydrogen bonds, adenine combines with thymine, and guanine with cytosine. Using this model, it was possible to trace the replication of the DNA molecule itself. According to Watson and Crick, two parts of a DNA molecule separate from each other at hydrogen bonding sites, much like undoing a zipper. From each half of the previous molecule, a new DNA molecule is synthesized. The sequence of bases functions as a template, or template, for the formation of new DNA molecules. The discovery of the chemical structure of DNA has been hailed throughout the world as one of the most outstanding biological discoveries of the century.
DNA plays an extremely important role in both the maintenance and reproduction of life. Firstly, it is the storage of hereditary information, which is contained in the nucleotide sequence of one of its chains. The smallest unit of genetic information after a nucleotide is three consecutive nucleotides - a triplet. Triplets located one behind the other, determining the structure of one chain, constitute a so-called gene. The second function of DNA is the transmission of hereditary information from generation to generation. DNA participates as a matrix in the process of transferring genetic information from the nucleus to the cytoplasm to the site of protein synthesis.
Watson, Crick and Wilkins received the 1962 Nobel Prize in Physiology or Medicine "for their discoveries about the molecular structure of nucleic acids and for their identification of their role in the transmission of information in living matter." In a speech at the presentation of A.V. Engström of the Karolinska Institute described DNA as “a polymer made up of several types of building blocks—monosaccharide, phosphate, and nitrogenous bases... Monosaccharide and phosphate are the repeating elements of the giant DNA molecule, and it also contains four types of nitrogenous bases. The discovery is the order in which these building blocks are spatially connected.”
What has this discovery changed in our lives over the past 50-plus years?
In 1969, scientists first synthesized an artificial enzyme, and in 1971, an artificial gene. At the end of the 20th century, it became possible to create completely artificial microorganisms. Thus, artificial bacteria were created in laboratories that produce unusual amino acids, as well as viable “synthetic” viruses. Work is underway to create more complex artificial organisms - plants and animals.
The study of the structure and biochemistry of DNA led to the creation of techniques for genome modification and cloning. In 1980, the first patent was issued for experiments with mammalian genes, and a year later a transgenic mouse with an artificially modified genome was created. In 1996, the first cloned mammal, Dolly the sheep, was born, followed by cloned mice, rats, cows and monkeys.
In 2002, the Human Genome Project was successfully completed, creating a complete genetic map of human cells. And in the same year, attempts at human cloning began, although none of them have been completed yet (at least, there is no scientific evidence of successful human cloning).
Back in 1978, insulin was created, almost completely identical to human insulin, and then its gene was introduced into the genome of bacteria, which turned into an “insulin factory.” In 1990, a gene therapy method was first tested, which saved the life of a four-year-old girl who suffered from a severe immune disorder. Currently, the study of the genetic mechanisms of the development of a variety of diseases - from cancer to arthritis - and the search for methods to correct the genetic “errors” that cause them are in full swing. In total, more than 350 drugs and vaccines are used in clinical practice, the creation of which uses genetic engineering.
DNA analysis has found wide application even in forensic science. It is used during trials to recognize paternity (by the way, this method has become a real gift for musicians, politicians and actors who were forced to prove in court their non-involvement in the birth of children attributed to them), as well as to establish the identity of the criminal. It is worth noting that James Watson himself spoke about this possibility of using DNA, proposing to create a database that would include the personal DNA structures of all the inhabitants of the planet, which would speed up the process of identifying criminals and their victims.
Using DNA, you can “catch” not only criminals, but also, for example, drugs or biological weapons. American criminologists are using a system to monitor the DNA structure of drug plants to create a database of all varieties of marijuana. This database will allow you to track the source of almost any drug sample. In the near future, DNA analysis-based methods for detecting biological attacks will begin to be used in the United States - it is planned to install special sensors in public places that will automatically “catch” dangerous microorganisms from the air and give a warning signal.
In 1982, the first successful modification of the plant genome was carried out. And five years later, the first agricultural plants with a modified genome appeared in the fields (these were tomatoes resistant to viral diseases).
Nowadays, almost all food products are grown using genetic engineering, especially crops such as soybeans and corn. Since 1996, when commercial use of genetically modified foods began, the total area under crops has increased 50-fold. The total area under transgenic crops in the world in 2005 amounted to 90 million hectares. True, the governments of many countries have banned the cultivation and import of such products, since a number of studies have shown that they can pose a danger to human health (allergies, damage to reproductive function, etc.).
The ability to study the structure of DNA has given new impetus to historical research. For example, the remains of Nicholas II and his family were identified, and some historical gossip was confirmed and refuted (in particular, it was proven that one of the founders of the United States, Thomas Jefferson, had illegitimate children from a black slave).
Using DNA analysis, it was possible to trace the origins of both people and entire nations. For example, it has been shown that the genes of the Japanese are almost identical to the genes of one of the Central American tribes. And for just $349, black Americans can find out what region of Africa and even what tribe their ancestors, brought on slave ships many years ago, came from.
What will DNA give us in the near future? Obviously, this will be the cloning of a person and his organs, which will solve the problem of the shortage of donor hearts and lungs for transplantation. New drugs will appear that will make incurable genetic diseases a thing of the past...
From the book 100 great geographical discoveries author Balandin Rudolf KonstantinovichPart 3 DUAL CONTINENT AMERICA
From the book Great Soviet Encyclopedia (DV) by the author TSB From the book Great Soviet Encyclopedia (SI) by the author TSB From the book Great Soviet Encyclopedia (SP) by the author TSB From the book 100 Great Mysteries of the 20th Century author Nepomnyashchiy Nikolai Nikolaevich From the book Jewish Business 3: Jews and Money author Lyukimson Petr Efimovich From the book Woman. Textbook for Men [Second Edition] author Novoselov Oleg Olegovich From the book 100 Great Holidays author Chekulaeva Elena OlegovnaDouble standard or principle of reciprocity? The author of any scientific, pseudoscientific or simply journalistic work telling about Jewish moneylenders, in search of an explanation for the hatred that the inhabitants of Europe experienced towards them and that he himself often experiences,
From the book Historical description of clothing and weapons of Russian troops. Volume 14 author Viskovatov Alexander Vasilievich From the book 20th century Encyclopedia of Inventions author Rylev Yuri IosifovichHappy Double A Day One of the most fun holidays in Vietnam is the Double Five Day, or Doan Ngo. It is celebrated on the first days of the 5th lunar month. The tradition of celebrating this day has its roots in ancient times and is connected, according to
From the book Woman. A manual for men. author Novoselov Oleg Olegovich From the author's book From the author's book7.3 Double standard A woman’s desire is the law, and a man’s desire is an article of the Criminal Code. Legal joke In any society and at all times there is a double standard in relation to the sexes, which is brought up from childhood in both sexes and then perceived as
Double fertilization sexual process in angiosperms in which both the egg and the central cell of the embryo sac are fertilized (See Embryo sac). Before. discovered by the Russian scientist S. G. Navashin in 1898 on 2 plant species - lily (Lilium martagon) and hazel grouse (Fritillaria orientalis). In D. o. both sperm are involved, brought into the embryo sac by the pollen tube; the nucleus of one sperm (See Sperm) fuses with the nucleus of the egg, the nucleus of the second fuses with the polar nuclei or with the secondary nucleus of the embryo sac. An embryo develops from a fertilized egg ,
from the central cell - Endosperm. In embryo sacs with a three-celled egg apparatus, the contents of the pollen tube are usually poured into one of the synergids (See Synergids) ,
which is destroyed (the remains of the synergid nucleus and the vegetative nucleus of the pollen tube are visible in it); the second synergid subsequently dies off. Next, both sperm, together with the modified cytoplasm of the pollen tube, move into the slit-like gap between the egg and the central cell. Then the sperm separate: one of them penetrates the egg and comes into contact with its nucleus, the other penetrates the central cell, where it contacts the secondary nucleus or one, and sometimes both, polar nuclei. Sperm lose their cytoplasm while still in the pollen tube or upon penetration into the embryo sac; sometimes sperm in the form of unchanged cells are observed in the embryo sac. With D. o. The nuclei of the embryo sac are in interphase (See Interphase) and are usually much larger than the nuclei of sperm cells, the shape and state of which can vary. In skerda and some other Asteraceae, the sperm nuclei have the appearance of a double twisted or crimped chromatin thread; in many plants they are elongated, sometimes crimped, more or less chromatized, and do not have nucleoli; usually sperm are round interphase nuclei with nucleoli, sometimes not different in structure from female nuclei. Based on the nature of the unification of male and female nuclei, it was proposed (E. N. Gerasimova-Navashina) to distinguish between two types of D. o.: premitotic - the sperm nucleus is immersed in the female nucleus, its chromosomes are despiralized; the union of the chromosome sets of both nuclei occurs in interphase (in the zygote); postmitotic - male and female nuclei, retaining their shells, enter prophase (See Prophase) ,
at the end of which their unification begins; interphase nuclei, containing chromosome sets of both nuclei, are formed only after the first mitotic division of the zygote. With D. o. In the egg, 2 haploid nuclei fuse, so the zygote nucleus is diploid. The number of chromosomes in the endosperm nuclei depends on the number of polar nuclei in the central cell and on their ploidy (See Ploidy) ;
Most angiosperms have 2 haploid polar nuclei and their endosperm is triploid. Consequence D. o. - Ksenia -
manifestation of dominant traits of the endosperm of the paternal plant in the endosperm of hybrid seeds. If several pollen tubes penetrate into the embryo sac, the sperm of the first one participates in pollen formation, while the sperm of the others degenerate. Cases of dispermia, i.e. fertilization of an egg by two sperm, are very rare. Lit.: Navashin S. G., Izbr. works, vol. 1, M.-L., 1951; Mageshwar and P., Embryology of Angiosperms, trans. from English, M., 1954; Poddubnaya Arnoldi V. A., General embryology of angiosperms, M., 1964; Steffen K., Fertilisation, in: Maheshwari P. (ed.). Recent advances in the embryology of angiosperms, Delhi, 1963. I. D. Romanov.
Great Soviet Encyclopedia. - M.: Soviet Encyclopedia. 1969-1978 .
See what “Double fertilization” is in other dictionaries:
Characteristic only of flowering plants. During double fertilization, one of the sperm fuses with the egg, and the second with the central cell of the embryo sac. An embryo develops from a fertilized egg, a secondary embryo develops from the central cell... ... Big Encyclopedic Dictionary
A type of sexual process characteristic only of flowering plants. Discovered in 1898 by S. G. Navashin in Liliaceae. Before. lies in the fact that when a seed is formed, not only the egg is fertilized, but also the center, the nucleus of the embryo sac. From a zygote... ...
double fertilization- A type of sexual process characteristic of flowering plants: one of the sperm fertilizes the egg, and the other (from the same pollen tube) fertilizes the central nucleus of the embryo sac; as a result of the first process, a diploid is formed... ... Technical Translator's Guide
Characteristic only of flowering plants. During double fertilization, one of the sperm fuses with the egg, and the second with the central cell of the embryo sac. An embryo develops from a fertilized egg, a secondary embryo develops from the central cell... ... encyclopedic Dictionary
Double fertilization double fertilization. A type of sexual process characteristic of flowering plants: one of the sperm fertilizes the egg, and the other (from the same pollen tube
Characteristic only of flowering zones. With D. o. one of the sperm fuses with the egg, and the second with the center. embryo sac cell. An embryo develops from a fertilized egg, from the center. cells are the secondary endosperm of the seed, containing... ... Natural science. encyclopedic Dictionary
double fertilization- the process of fertilization that occurs in angiosperms, in which both spermatozoa are formed. One of them fuses with the egg, the second - with the central diploid cell of the embryo sac. Discovered by S. G. Navashin in... ... Anatomy and morphology of plants
DOUBLE FERTILIZATION- a sexual process in angiosperms, consisting in the fusion of one male gamete of the pollen tube (sperm) with the egg of the embryo sac, and the second male gamete with the secondary nucleus of the embryo sac... Dictionary of botanical terms
double fertilization according to nawashin- PLANT EMBRYOLOGY DOUBLE FERTILIZATION ACCORDING TO NAVASHINA - the fusion of an egg and a sperm to form a zygote (2p) and the simultaneous fusion of another sperm and a double nucleus to form the primary endosperm nucleus (3p). A characteristic feature of all... General embryology: Terminological dictionary
Syngamy, the fusion of a male reproductive cell (sperm, sperm) with a female (egg, ovum), leading to the formation of a zygote, gives rise to a new organism. In animals O. is preceded by insemination. In the process of O., the egg is activated,... ... Biological encyclopedic dictionary
James Dewey Watson - American molecular biologist, geneticist and zoologist; He is best known for his participation in the discovery of the structure of DNA in 1953. Winner of the Nobel Prize in Physiology or Medicine.
After successfully graduating from the University of Chicago and Indiana University, Watson spent some time doing chemistry research with biochemist Herman Kalckar in Copenhagen. He later moved to the Cavendish Laboratory at the University of Cambridge, where he first met his future colleague and comrade Francis Crick.
Watson and Crick came up with the idea of a DNA double helix in mid-March 1953, while studying experimental data collected by Rosalind Franklin and Maurice Wilkins. The discovery was announced by Sir Lawrence Bragg, director of the Cavendish Laboratory; This happened at a Belgian scientific conference on April 8, 1953. The important statement, however, was not actually noticed by the press. On April 25, 1953, an article about the discovery was published in the scientific journal Nature. Other biological scientists and a number of Nobel laureates quickly appreciated the monumentality of the discovery; some even called it the greatest scientific discovery of the 20th century.
In 1962, Watson, Crick and Wilkins received the Nobel Prize in Physiology or Medicine for their discovery. The fourth participant in the project, Rosalind Franklin, died in 1958 and, as a result, could no longer qualify for the prize. Watson was also awarded a monument at the American Museum of Natural History in New York for his discovery; since such monuments are erected only in honor of American scientists, Crick and Wilkins were left without monuments.
Watson is still considered one of the greatest scientists in history; however, many people openly disliked him as a person. James Watson has been involved in quite high-profile scandals several times; one of them was directly related to his work - the fact is that while working on the DNA model, Watson and Crick used data obtained by Rosalind Franklin without her permission. The scientists worked quite actively with Franklin's partner, Wilkins; Rosalind herself, quite possibly, might not have known until the end of her life how important the role her experiments played in understanding the structure of DNA.
From 1956 to 1976, Watson worked at Harvard's biology department; During this period he was interested mainly in molecular biology.
In 1968, Watson received a position as director of the Cold Spring Harbor Laboratory in Long Island, New York; Through his efforts, the quality of research work in the laboratory has significantly increased, and funding has noticeably improved. Watson himself was primarily involved in cancer research during this period; Along the way, he made the laboratory under his control one of the best centers of molecular biology in the world.
In 1994, Watson became president of the research center, and in 2004 - rector; in 2007, he left his position after making rather unpopular statements about the existence of a connection between intelligence level and origin.
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