Heredity

Heredity – the passing of traits from parent to offspring. Dominant traits – one trait that appears and other disappears. Recessive traits – trait that is masked by the dominant gene.

Genes Genes – each parent donate a set of characteristic instructions to offspring. Alleles – 2 forms of a gene – 1 from each parent Genotype – inherited combo of alleles. Phenotype – an organisms appearance Probability – mathematical chance that an event will occur.

Gregor Mendel He lived in Austria in He was a monk that studied pea plants to learn about heredity. When Gregor breeds pea plants he noticed that one trait always appeared and the other disappeared. He concluded that each parent must donate one set of chromosomes to the offspring = genes Two forms of a gene = alleles Gene – eye color / allele – brown & blue

Punnett Square The punnett square is used to show possibilities of offspring. Genotype = inherited combo of alleles Capital letters are dominant Lowercase letters are recessive Dominant letter always appears first The chance that an event will occur = probability. Each box in the Punnett Square equals 25%.

Mitosis vs. Meiosis Mitosis is the process where body cells are reproduced. Mitosis is part of the cell cycle. (4 out of 6 steps) Mitosis produces 2 cells that are identical to the original body cell. Mitosis copies chromosomes once and divides once. Meiosis is the process where sex cells are reproduced. Meiosis has 8 steps. Meiosis produces 4 cells that have half of the genetic information in each cell. Meiosis copies the chromosomes once and divides the cells twice.