Cell Division Notes Biology

Vocabulary Mitosis: process of normal cell division, results in 2 identical cells Meiosis: cell division involving gametes where number of chromosomes are cut in half Homologous: chromosome from each parent match (the same) Diploid: (double) two complete sets of inherited chromosomes

Vocabulary Haploid: single set of chromosomes (half) Zygote: fertilized egg Gamete: specialized cells involved in sexual reproduction cells (sex cells, sperm and ova) DNA: deoxyribonucleic acid = genetic information

Why do cells divide? Cells need to divide in order to: Create more cells for the organisms to grow Replace old cells Create reproductive cells

Types of Cell Division Cell Cycle Meiosis Includes Mitosis Used for creating more cells for organism growth and repair or replacement Makes two identical copies Meiosis Used for creating reproductive cells Makes four cells with half the genetic information in each

What is a chromosome? Chromosome: a structure made of coiled DNA, formed during cell division Made up of two sister chromatids held by a centromere

Cell Cycle Drawing, draw and label the phases

End Result of Cell Cycle Cell Cycle ends in two identical cells called daughter cells

Meiosis Why meiosis? Chromosome number must be split in two Cells are diploid (two sets of chromosomes) Reproductive cells (sperm and eggs) are haploid (only one set of chromosomes) How is it different from the cell cycle (mitosis)? Requires two cell divisions Each cell contain ½ of the chromosomes (genetic material)

Homologous Chromosomes What is a homologous chromosome? The pair of chromosomes from each parent Ex: Homologous chromosome 1: 1 from Mom and 1 from Dad

Meiosis Parts of Meiosis Meiosis 1: homologous chromosomes separate Meiosis 2: sister chromatids separate, four haploid cells are formed

Meiosis

Compare and Contrast Mitosis and Meiosis On your own paper, answer the following: 1. How are the two processes different? 2. How are the two processes the same? 3. How are the end results the same? 4. How are the end results different? 5. What types of cells do each process?