Questions and Answers
Which scientist first proposed that certain chromosomes determine sex?
What term was introduced by Bateson in 1906?
What did Archibald Garrod discover in 1902 regarding diseases?
Which year did Mendel's work experience a significant rediscovery by three scientists?
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Which scientist was associated with the observation of chromosomes specifically in grasshopper cells?
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Which term did Wilhelm Johannsen use to describe the outward appearance of an organism?
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Who is credited with mapping the genes on the fruit fly’s sex chromosome?
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What significant method did Kary Mullis contribute to the field of genetics in 1983?
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Which two scientists proposed the double-stranded helix structure of DNA?
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What important discovery did Frederick Griffith make in 1928 related to bacteria?
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What did Erwin Chargaff find about the composition of DNA in 1949?
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Which of the following best describes the concept of transformation discovered by Frederick Griffith?
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In 1987, which researchers analyzed mitochondrial DNA to conclude that humans share a common ancestor?
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Who first sequenced the human gene in 1989?
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Who proposed the continuity theory of germ plasm, which emphasizes the transference of hereditary factors?
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What discovery did H. Fol and O. Hertwig contribute to in relation to fertilization?
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Which scientist postulated that chromatin within the nucleus has a linear organization that must be crucial for heredity?
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What was one of the significant limitations faced by Gregor Mendel in analyzing heredity?
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How did the contributions of Van Beneden and Boveri relate to the field of cytogenetics?
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According to the principles of Mendelian genetics, what term describes the separation of alleles during gamete formation?
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What is the primary focus of the germ theory as proposed by Weismann?
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What was the significant conclusion from the discoveries regarding fertilization in both animals and plants?
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Study Notes
Key Discoveries in Genetics
- Gregor Mendel published findings on inheritance in pea plants, establishing foundational genetics laws in 1865.
- Theodor Boveri posited that chromosomes play a crucial role in inheritance in 1890.
- Walter Sutton observed chromosomes in grasshopper cells, supporting Boveri's ideas around 1900.
- Mendel's work was rediscovered in 1900-1901 by Hugo De Vries, Erich von Tschermack, and Carl Correns.
- Archibald Garrod identified that some diseases must be inherited in 1902.
- In 1903, Sutton and Boveri noted that each egg or sperm cell contains one chromosome from each pair.
- Edmund Beecher Wilson and Nettie Stevens independently described sex-determining chromosomes in 1905, establishing that a single Y chromosome determines maleness.
- Bateson introduced the term "genetics" in 1906, laying groundwork for the field.
- Wilhelm Johannsen, in 1909, coined terms like "gene," “genotype,” and “phenotype” to describe hereditary mechanics.
Advancements in Genetic Research
- Thomas Hunt Morgan demonstrated that genes reside on chromosomes by 1910, merging cell study with heredity.
- Alfred Henry Sturtevant created the first gene map on the fruit fly's sex chromosome between 1911-1913.
- Sir William Henry Bragg and his son showed X-rays can reveal molecular structures, including crystals like salt, in 1912.
- Morgan authored the ‘Theory of the Gene’ in 1926, advancing genetic principles.
- Frederick Griffith discovered bacterial 'transformation' in 1928, marking a significant step in understanding genetics.
- In 1944, Oswald Avery, Colin MacLeod, and Maclyn McCarty confirmed DNA as hereditary material using bacteria.
- Erwin Chargaff discovered complementary base pairing laws between adenine-thymine and guanine-cytosine ratios in DNA in 1949.
- James Watson and Francis Crick proposed the double-stranded helix model of DNA in 1953.
Molecular Biology and DNA Research Breakthroughs
- Between 1963-1966, Marshall Nirenberg and Heinrich Matthaei deciphered the genetic code.
- In 1977, the first viral DNA was sequenced by Frederick Sanger, Walter Gilbert, and Allan Maxam independently.
- Kary Mullis invented the Polymerase Chain Reaction (PCR) in 1983, revolutionizing DNA amplification techniques.
- Rebecca Cann, Mark Stoneking, and Allan Wilson analyzed mitochondrial DNA in 1987, asserting that all humans share a common ancestor from 200,000 years ago.
- Francis Collins and Lap-chee Tsui sequenced the first human gene in 1989, marking significant progress in genetic mapping.
Contributions to Genetic Theory and Cell Biology
- Notable figures like Van Beneden, Flemming, and Strasburger observed germ cells, supporting Weismann's germ plasm theory from 1883.
- Weismann proposed the continuity of hereditary factors through germ plasm, located in sex cells, rather than somatic cells.
- O. Hertwig predicted fertilization in animals, later observed directly by H. Fol in 1879.
- Strasburger directly observed fertilization in plants, linking cell nuclei to heredity.
- Roux suggested a linear organization of chromatin within chromosomes.
- Weismann emphasized the orderly arrangement of hereditary units along chromosomes, integrating genetic inheritance with cell biology.
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Description
Explore the groundbreaking discoveries in genetics from the early 20th century. This quiz covers significant contributions such as Sturtevant's mapping of fruit fly genes and the introduction of X-ray techniques by the Braggs. Test your knowledge on key figures and concepts that shaped the field of genetics.
