Content Standard 9 Identify the process of chromosome reduction in the production of sperm and egg cells during meiosis

Eligible Content Describe and identify the process of chromosome reduction in the production of sperm and egg cells during meiosis Define haploid Define diploid

MEIOSIS Meiosis – reduction division Meiosis – reduces the chromosome number by ½ of the parents cell’s chromosome number. Meiosis – produces gametes (sex cells) Meiosis – male = sperm eggs / female=egg cells Meiosis – guarantees genetic diversity (variations) Meiosis- Gametes or sex cells are called haploid Haploid = ½ the original chromosome number Humans (haploid number = 23) Egg cell (each have 23 chromosomes) Sperm cells (each have 23 chromosomes )

Meiosis START One diploid cell ENDFour haploid cells (1/2 of the parent cell’s chromosome number) Humans Diploid = 46 Interphase ( chromosome # doubles b/c of replication) 46 * 2 = 92 Prophase 1 Metaphase 1 Anaphase 1 ( 92 separate two sets of 46) Telophase 1

Meiosis contiunes Telophase 1 One cell divides = two cells each w/46 Prophase II No replication Metaphase II Anaphase II two cells each w/46 chromosomes / 46 chromosomes separate Telophase II two cells complete division = four cells each cell has 23 chromsomes

MEIOSIS (1 diploid = 4 Haploid) 46 Diploid 23 Haploid 23 Haploid 23 Haploid 23 Haploid Egg or sperm

Meiosis ( Egg/Sperm) A. Species has 4 chromosomes What would the egg or sperm cell look like? B. Species has 2 chromosomes What would the egg or sperm cell look like? C.Egg or sperm has 8 chromosomes How many chromosomes would the organism or body cells have?

Diploid = 4 chromosomes Chromosome Which diagram represents the egg or sperm? Cell (A) Cell (B) Cell (C) Cell (D)

Diploid = 4 chromosomes Chromosome Cell B Diploid = 4 chromosomes Haploid / egg or sperm = ½ = 2 chromosomes

Species has TWO chromosomes What would the egg or sperm cell look like? Cell C Cell D Cell B Cell A

B. Species has 2 chromosomes What would the egg or sperm cell look like? CELL A Cell A Diploid = 2 chromosomes Haploid /egg or sperm = ½ = 1 chromosome

HAPLOID CELLS HAPLOID Egg Cells Sperm Cells ONLY SEX cells Gametes

DIPLOID CELLS = BODYor somatic Cells BODY Cells Plant Leaf cells Stem cells Root cells NOT sex cells NOT egg or sperm or gametes

Egg or sperm has 2 chromosomes. How many chromosomes in the organism? Cell A Cell B Cell D Cell C

Egg or sperm has 2 chromosomes. How many chromosomes in the organism? Cell D Egg or sperm = 2 Organism or body cells = diploid # 2 (2) = 4