Nicholas Olofsson and Elissa Harris Period 3

Meiosis Process that converts diploid nuclei into haploid nuclei Occurs in the sex organs-testes and ovaries Produces gametes- sperm and eggs Divided into Meiosis 1 and Meiosis 2

Cell division that reduces the chromosome number by half Meiosis 1

Meiosis 2 No interphase 2 and similar to mitosis

Questions: What is one advantage and disadvantage of asexual reproduction? What is one advantage and disadvantage of sexual reproduction? How does meiosis ensure genetic diversity? When does independent assortment and crossing over occur during meiosis? List three ways mitosis and meiosis are similar. List three ways mitosis and meiosis are different.

Genetics The study of heredity or how traits are passed for parents to offspring Traits are distinguishing qualities pr characteristics

Mendel’s Laws Law of Segregation Two members of a gene pair separate from each other in the formation of gametes Half the gametes carry one allele and the others carry the other Law of Dominance The trait that shows in a heterozygous individual is dominant and the hidden trait is recessive Law of Independent Assortment A particular allele for one trait can be paired with either allele of another trait

Exceptions Incomplete Dominance Heterozygous alleles have a phenotype that is in between two homozygotes Codominance When both alleles are fully expressed usually in a pattern

Punnet Squares Diagram used to predict outcome of genetic cross Phenotype: observable trait Genotype: combination of alleles

Pedigrees and Karyotypes Pedigree: recorded ancestry of a person or family Karyotype: organized profile of a person’s chromosomes

Questions: The outward appearance (gene expression) of a trait in an organism is referred to as: A. genotype B. phenotype C. an allele D. independent assortment What is the ratio for a dihybrid cross between parents that are heterozygous for both traits? The mating of two curly-haired brown guinea pigs results in some offspring with brown curly hair, some with brown straight hair, some with white curly hair, and even some with white straight hair. This mating illustrates which of Mendel's Laws? A. Dominance B. Segregation C. Independent Assortment D. Sex-Linkage