Prentice Hall- Science Explorer- Cells and Heredity
Chapter 3- The Science of Heredity
Section 3- The Cell and Inheritance
Questions- Comments- Key Words- ConnectionsMeiosis |
Main Ideas; Visuals + PredictionsChromosomes and Inheritance
* Sutton found that body cells of a grasshopper have 24 chromosomes. And that the grasshopper' s sex cells have only 12 chromosomes. * In other words, a grasshopper’s sex cells have exactly half the number of chromosomes found in its body cells. Genes on Chromosomes
* According to the chromosome theory of inheritance, genes are carried from parents to their offspring on chromosomes.
Meiosis Meiosis: The process that occurs in the formation of sex cells (sperm and egg) by which the number of chromosomes is reduced by half. What happens during Meiosis? * During meiosis, the chromosome pairs separate and are distributed to two different cells. The resulting sex cells have only half as many chromosomes as the other cells in the organism. |
Meiosis and Punnett Square
* A Punnett square is a way to show the events that occur at meiosis. In the figure below you can see how the Punnett square portrays the separation of alleles during meiosis. A Lineup of Genes
*The body cells of humans contain 23 chromosome pairs, or 46 chromosomes. Chromosomes are made up of many genes joined together like beads on a string. |