6.2 DNA Replication

Watson and Crick’s model predicts that when a double helix replicates, each of the two daughter molecules will have one old strand, from the parental molecule, and one newly made strand.
Watson and Crick’s model predicts that when a double helix replicates, each of the two daughter molecules will have one old strand, from the parental molecule, and one newly made strand.
The elegant double-helical structure of deoxyribonucleic acid (DNA) shook the scientific world when it was proposed in April 1953 by James Watson and Francis Crick. The DNA you inherited from your parents contains all your genes—your genetic information.
优秀海报作业展示:Chemistry of Life, Cell Structure and Function, Cellular Energetics.
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Chromosomal inheritance can result in mutations that increase genetic diversity but can also cause genetic disorders. Sexual reproduction can increase genetic diversity by creating offspring with extra or missing chromosomes.
Another departure from simple Mendelian genetics arises when the phenotype for a character depends on environment as well as genotype.
In the 1900s, geneticists extended Mendelian principles not only to diverse organisms, but also to patterns of inheritance more complex than those described by Mendel.
Modern genetics began during the mid-1800s with a monk named Gregor Mendel, who discovered the basic principles of heredity by breeding garden peas in carefully planned experiments.
Gamete formation involves a type of cell division called meiosis. This type of cell division reduces the number of sets of chromosomes from two in the parent cell to one in each gamete, counterbalancing the doubling that occurs at fertilization.
Levels of proteins called cyclins increase and decrease during the cell cycle. Cyclins were discovered in studies of mitosis in sea urchin gametes.