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Genetics. What’s it all about?. Questions: what we will answer . What is genetics? How do chromosomes work? What is the history of genetics? Genetics and probability: What are Punnett Squares? How does the study of genetics affect our lives? What is the future of genetics?.
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Questions: what we willanswer. • What is genetics? • How do chromosomes work? • What is the history of genetics? • Genetics and probability: What are Punnett Squares? • How does the study of genetics affect our lives? • What is the future of genetics?
Genetics is the science of heredity. • Heredity - the passing of traits from parents to offspring. • Traits - characteristics or features of an individual, not always apparent or obvious
Chromosomes: the mechanisms that make it all possible • Chromosomes are in pairs, found in the nuclei of cells. • A single chromosome is composed of many genes, which determine hereditary traits. • Chromosomes are made of a molecule called deoxyribonucleic acid (DNA). • Human cells contain 46 (23 pairs) of chromosomes totally about 35,000 genes on them. • There are 2 to the 23rd power (or 8,388,608) possible gene combinations. • Gametes (sex cells : sperm and eggs) contain only half the number of chromosomes.
Chromosomes are made of DNA. Segments of chromosomes are called genes.
Deoxyribonucleic Acid (DNA) • The double helix shape resembles a spiral staircase. • The shape was first correctly identified in 1953 by James Watson and Francis Crick, who then won the Nobel prize in 1962. • The unique shape allows the molecule to “unfold” or “unzip” along a portion of the molecule. • When a strand of DNA “unzips”, an exact copy of the “unzipped” portion can be replicated (copied) • DNA replication is how cells make proteins, which build new cells, repair cells, and many other functions that keep the cells functioning.
DNA replication (making copies) • The unique shape of DNA allows the molecule to “unzip” along a portion of the strand. • When a strand of DNA “unzips”, an exact replica of the “unzipped” portion can be replicated (copied) • DNA replication is how cells make proteins, which build new cells, repair cells, and countless other functions that keep cells functioning. • DNA replication is happening constantly in cells.