Meiosis vs Mitosis Mitosis is asexual reproduction of

Meiosis vs. Mitosis • Mitosis is asexual reproduction of cells, where one cell divides to create more cells. The copies made are identical to the parent and to each other. Most cells in your body and single celled organisms reproduce this way.

Sexual Reproduction • In sexual reproduction, two parent cells join together to create offspring that are different from both parents. • These parent cells are called sex cells, and they are different from normal cells in the body. • Most cells in the body have 46 chromosomes (23 matching pairs). These are called homologous chromosomes because they have the same gene sequence and structure. • Human sex cells are different, they only have half of the usually number. They have 23 chromosomes… or HALF of the information.

Meiosis • Sex cells are made during meiosis. This is the copying process that produces cells with half the usual number of chromosomes. • For example, a human egg cell has 23 chromosomes and a sperm cell has 23 chromosomes. They both have half of the information. • The new cell that forms when these two cells meet will have 46 chromosomes. • https: //www. youtube. com/watch? v=to. WK 0 f. Iy. Fl. Y

The steps • During mitosis, chromosomes are copied once, and then the nucleus divides once. • During meiosis, chromosomes are copied once, and then the nucleus divides twice.

Sex Chromosomes • Sex chromosomes are one of the pair of chromosomes that determine the sex of an individual. • Male is XY and female is XX.

Sex-Linked Disorders • Sex-linked genetic diseases caused by a single-gene defect are recessive and affect males almost exclusively. • Why? Females possess two X chromosomes; males possess an X and a Y. For a sex-linked disorder to manifest itself in a female, both of her X chromosomes would have to carry the defective gene, meaning the girl's father would have been affected by the disorder. Colorblindness is an example of this.

Genetic Counseling and Selective Breeding • Since genetic diseases can be traced through a family tree, sometimes a pedigree is made to trace the chances of passing along the disease. • A pedigree is a diagram that shows the occurrence of a genetic trait in several generations of a family. • Selective breeding in plants and animals has been practiced for thousands of years. This is where you choose organisms with desirable traits and breed them together to get offspring with these traits.

Can you make a pedigree of your families eye color? • Show me here!