210 likes | 385 Views
Mitosis, Meiosis and Reproduction. The Cell Cycle. Interphase Mitosis Prophase Metaphase Anaphase Telophase Cytokinesis. The Cell Cycle.
E N D
Mitosis, Meiosis and Reproduction
The Cell Cycle • Interphase • Mitosis • Prophase • Metaphase • Anaphase • Telophase • Cytokinesis
The Cell Cycle • Interphase – The “holding” stage between two successive cell divisions. Approximately 90% of a cell’s life is spent here. Before mitosis begins, organelles and chromosomes duplicate. • Mitosis • Prophase • Metaphase • Anaphase • Telophase • Cytokinesis
The Cell Cycle • Interphase • Mitosis – a series of steps in which the nucleus divides to form two nuclei identical to each other and identical to the original nucleus. • Prophase • Metaphase • Anaphase • Telophase • Cytokinesis
The Cell Cycle • Interphase • Mitosis • Prophase - chromatin condenses into distinct chromosomes, centrioles migrate to opposite ends of the cell and nuclear membrane breaks down • Metaphase • Anaphase • Telophase • Cytokinesis
The Cell Cycle • Interphase • Mitosis • Prophase • Metaphase – chromosomes line up on the metaphase plate • Anaphase • Telophase • Cytokinesis
The Cell Cycle • Interphase • Mitosis • Prophase • Metaphase • Anaphase – sister chromatid separate and move to opposite poles of the cell • Telophase • Cytokinesis
The Cell Cycle • Interphase • Mitosis • Prophase • Metaphase • Anaphase • Telophase – chromosomes arrive at the poles and a new nuclear envelope forms around each set • Cytokinesis
The Cell Cycle • Interphase • Mitosis • Prophase • Metaphase • Anaphase • Telophase • Cytokinesis – division of the cytoplasm
23 46 23
Vocabulary Chromosome – a linear thread of DNA and its associated proteins
Vocabulary • Haploid – cell with half the number of chromosomes as body cells • Diploid – cell that has two copies of each chromosome • Zygote – the diploid cell formed when a sperm fertilizes an egg; will divide by mitosis and develop into a new organism.
Vocabulary • Meiosis – a special type of cell division that produces four haploid cells from one diploid cell to ensure offspring will have the same number of chromosomes as the parent organism. It is divided into two steps: Meiosis I and Meiosis II http://highered.mcgraw-hill.com/olcweb/cgi/pluginpop.cgi?it=swf::535::535::/sites/dl/free/0072437316/120074/bio19.swf
Meiosis • Interphase: genetic material is duplicated • Meiosis I • Prophase 1: nuclear membrane disappears, each chromosome consists of two, closely associated sister chromatids and crossing-over can occur during this stage. • Metaphase 1: Homologous chromosomes align in the center of the cell • Anaphase 1: Homologous pairs separate with sister chromatids remaining together. • Telophase 1: Two daughter cells are formed with each daughter containing only one chromosome of the homologous pair. Nuclear membrane reforms.
Meiosis • Meiosis II • Second division of meiosis: Gamete formation • Prophase 2: DNA does not replicate. • Metaphase 2: Chromosomes align at the equatorial plate. • Anaphase 2: Centromeres divide and sister chromatids migrate separately to each pole. • Telophase 2: Nuclear division is complete. Four haploid nuclei are obtained. • Cytokinesis - Four haploid daughter cells are obtained.