Answer:214
Explanation:
James Watson and Francis Crick, along with the help of Rosalind Franklin's X-ray crystallography data, are credited with first identifying the structure of DNA as a double helix.
The identification of the structure of DNA as a double helix is one of the most significant discoveries in the history of biology. In 1953, James Watson and Francis Crick, both scientists at the University of Cambridge, proposed the double helix model for DNA based on their understanding of its molecular properties and the X-ray crystallography data provided by Rosalind Franklin and her colleague Maurice Wilkins.
Rosalind Franklin, a talented biophysicist, used X-ray crystallography to study the molecular structure of DNA fibers. Her X-ray diffraction images, including Photo 51, provided crucial insights into the helical nature of DNA and its dimensions. Although she did not directly contribute to the final model proposed by Watson and Crick, her work was instrumental in guiding their understanding of DNA's structure.
In April 1953, Watson and Crick published their landmark paper in the journal Nature, titled "Molecular Structure of Nucleic Acids: A Structure for Deoxyribose Nucleic Acid." In this paper, they described the double helix model of DNA, with the two strands forming a twisted ladder-like structure, and the base pairs holding the strands together like rungs on the ladder.
The identification of DNA's structure as a double helix provided a crucial foundation for understanding how genetic information is stored and transmitted in living organisms. This discovery paved the way for advancements in genetics, molecular biology, biotechnology, and other fields, transforming our understanding of life at the molecular level and earning Watson, Crick, and Wilkins the Nobel Prize in Physiology or Medicine in 1962.
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Answer:
Friedrich Miecher was the Swiss chemist who first identified DNA in 1860. It was first identified in the nuclein which is found inside nuclei of the human white blood cells. The nuclein was later on named as nucleic acid. The type of nucleic acid was identified as deoxyribonucelic acid.
b. fertilization.
c. gastrulation.
d. cleavage.
e. growth.
The answer is (b.) fertilization
The fertilization is the stage where the egg cell or the so-called ovum fused with the sperm cell which eventually leads the development of the embryo or the zygote. The Embryogenesis starts when the zygote undergoes mitotic divisions or also known cleavage process.
b.Na+ and K+ leaks
c.Na+ cotransporter
d.Na+-K+ ATPase
The Na+-K+ ATPase, a membrane protein pump, prevents the sodium (Na+) and potassium (K+) gradients from dissipating by actively transporting these ions against their concentration gradients.
The mechanism that prevents the Na+ and K+ gradients from dissipating is the Na+-K+ ATPase. This is an integral membrane protein pump found in almost all animal cell membranes. This pump carries out the function of moving 3 sodium ions out of the cell and 2 potassium ions into the cell during each cycle of pumping. This is done at the expense of one ATP (adenosine triphosphate) molecule, hence the name ATPase. This active transport work against the concentration gradients of these ions, hence maintaining their respective gradients across the cell membrane.
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The Current Would Increase In Speed
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The Cycle And Movements Of Water Link Below
b. parasitism because the insect lives off the nectar from the flower.
c. commensalism because the insect does not harm the flower and the flower does not benefit from the relationship.
d. predation because the insect feeds on the flower.
Answer: A) Mutualism
Explanation:
The insect pollinates the flower, and the insect obtains food from it at the same time.