Genetics and Punnett Squares Bellwork What is the

Genetics and Punnett Squares Bellwork: What is the difference between a dominant gene and a recessive gene?

Cells and Cell Division �Cells �Basic are the basis of genetic activity structure of all living things �All plant and animal life begins as a single cell �The nucleus contains pairs of chromosomes on which genes rests at specific locations

Mitosis �Animal growth and reproduction takes place via cell division �Mitosis: �DNA Simple cell division for growth replicates and then is passed on to each divided cell

Meiosis �Meiosis: Cell division that results in the formation of gametes or sex cells �Chromosomes divide and one is passed on to each new cell �A chromosome from each parent combines with the chromosome from the other parent and genetic recombination occurs

Genes �Genes- units of genetic material �Genes occur at specific locations on chromosomes �In pairs of genes the genes may be alike or different

Homozygous Vs. Heterozygous �Homozygous- pairs of genes that are alike �Heterozygous- pairs of genes that are different �When two genes in a pair are different, one usually expresses itself while the other does not …. . dominant vs. recessive

Genotype Vs. Phenotype �Genotype- the actual configuration of genes �Phenotype- animal Physical appearance of the

Dominant and Recessive Traits in Humans �Eye Color- Brown Dominant; Color Recessive �Tongue rolling- Can roll Dominant; Cannot Roll; Recessive �Thumbs- Straight Thumb Dominant; Curved Thumb Recessive

Punnet Square Example � 2 Individuals one can roll their tongue and the other cannot �Male can roll his tongue and has a heterozygous genotype Rr �Female cannot roll her tongue and has a homozygous genotype rr