CHAPTER 5: CELLULAR REPRODUCTION

REPRODUCTION It is the process by which an organism produces offspring either sexually or asexually. Its main purpose is for the perpetuation of speciesCELL DIVISION It is the process of cell reproduction following several stages to produce two daughter cells. It is often referred to as CELLULAR REPRODUCTION.Mitosis Promoting Factor (MPF) Protein triggering agent for cell division.TYPES OF CELL DIVISIONa. MEMBRANE GROWTHb. MITOSIS (eukaryotic cells)c. MEIOSIS (eukaryotic cells)Membrane Growth The process wherein cells partition their genetic material among prokaryotic cell.Mitosis The process of nuclear division in which duplicated chromosomes are separated from one another, producing nuclei, each with one copy of each chromosomes. Comes from the Greek word mitos, meaning thread. Mitosis is usually accompanied by cytokinesis, resulting in two daughter cells with genetic potential identical to each other and the parent cell which they arose.Meiosis This is a type of cell division that occurs only in reproductive cells or gametes. Meiosis occurs only in diploid cells and produces four daughter nuclei, each containing haploid number of chromosomes.The Cell Cycle The stages through which a cell passes from one cell division to the next. Two main stages ( *Interphase * M phase )Interphase The longest phase in the cell cycle of a typical cellM Phase Two main steps Mitosis is a series of phases in cell division during which the nucleus of cell divides into two nuclei with identical genetic material. Cytokinesis is the process during which the cytoplasm of the cell divides into two new cells, called daughter cellsStages in Mitosis Interphase The period between cell division. The genetic material is in the form of chromatin. Centrosomes, a small oval body, is found just outside the nuclear membrane. This is true in animal cell but not in plant cell. Prophase Chromatin shortens and thickens. DNA in chromatins replicated. Chromatin now becomes chromatid which is held together at a single point by a centromere Metaphase Chromosomes move toward the middle of the spindle fiber. Anaphase Chromatids separate and begin to travel away from each other towards opposite poles. Telophase In animal cells, centrosomes reappear Cytokinesis In animal cells, cytokinesis results when a fiber ring composed of a protein called actin around the center of the cell contracts pinching the cell into two daughter cells, each with one nucleusCHAPTER 5: CELLULAR REPRODUCTION

Chromosome Number In humans, each gamete contains 23 chromosomes. All body cells contain two complete sets of chromosomes, which in human is 46 chromosomes.Diploid The cell with two complete sets of chromosomeHaploid one complete set of chromosomesTumor - abnormal growths of cells. Benign Tumor cells remain together and usually cause little harm. Benign tumors can be often removed by surgery. Malignant Tumor cells do not remain together. They break free from a tumor and migrate to a new locations in the body. The malignant cells can start new tumors in new locations. Cancer The spread of malignant cells to a new location. Cancer cells can spread freely because they lack the surface proteins that bind the normal cells together.Types of Reproduction Asexual reproduce without the use of gametes or sex cells. One parent organism can reproduce by itself. Sexual requires the union of male and female gametes called fertilization.Sperm - Male gametesEgg or Ova - Female gametes

Asexual Reproduction Budding a parent organism produces offspring by growing a tiny replica of itself called a bud, on some part of its body. Fragmentation separated pieces of the parent organism can develop into new individuals Vegetative Reproduction new plants grow from the stems, roots, or leaves of an existing plant Fission splitting of organism body into 2 identical parts Sporulation spore formation as in fern plant and mushrooms. Regeneration The ability of some animals to grow entire body parts lost through accident or injury.Pollination the transfer of pollen grains from the another of one flower to the stigma of another flowerSelf Pollination - the transfer of pollen grains of one flower to the stigmata of the same flower.Cross Pollination - the transfer of pollen grains of one flower to the stigmata of another flowerAgents of Pollination Wind Water Animals man FERTILIZATION - The union of male gametes and female gametesZYGOTE - The single cell that results from fertilization. The zygote contains two complete sets of chromosomes and therefore diploidHOMOLOGOUS PAIRS - The matching pairs of chromosomes in a diploid cell.CROSSING OVER - It is the exchange of genes between pairs of homologous chromosomes.