Cell Reproduction Chromosomes Mitosis Meiosis Chromosomes Mitosis Meiosis

Chromosomes

Cell Division Cell Division is the process by which cells reproduce. information in the cell is contained in genes → genes code for proteins → proteins carry out cellular functions Each body cell that results from cell division must have an exact copy of the DNA in the original cell. Cell Division is the process by which cells reproduce. information in the cell is contained in genes → genes code for proteins → proteins carry out cellular functions Each body cell that results from cell division must have an exact copy of the DNA in the original cell.

Chromosome Structure

Chromosome Number

Karyotype

Diploid vs. Haploid Diploid (2n): a cell that contains both chromosomes of a homologous pair Humans = 46 (somatic cells: body cells) Haploid (n): a cell that has only one chromosome of each homologous pair Humans = 23 (gametes: egg and sperm) Diploid (2n): a cell that contains both chromosomes of a homologous pair Humans = 46 (somatic cells: body cells) Haploid (n): a cell that has only one chromosome of each homologous pair Humans = 23 (gametes: egg and sperm)

Mitosis

Mitosis: the division of the cell nucleus in which the chromosomes in the parent cell divide into two identical sets In somatic cells (body cells), the number of cells is increased without changing the information contained in the DNA or the amount of DNA in those cells. Mitosis: the division of the cell nucleus in which the chromosomes in the parent cell divide into two identical sets In somatic cells (body cells), the number of cells is increased without changing the information contained in the DNA or the amount of DNA in those cells.

Binary Fission Binary Fission: cellular division of unicellular organisms that produces identical offspring

Cell Cycle

Overview

Important Structures Asters Centrioles Polar Fibers Kinetechore Fibers Equator Kinetechore

Mitosis in Animals

G 1 Normal growing cell DNA = chromatin Organelles are doubling (not shown) G 1 Normal growing cell DNA = chromatin Organelles are doubling (not shown) S DNA Replication G 2 Final Preparation for Mitosis S DNA Replication G 2 Final Preparation for Mitosis Prophase Chromosome formation Nucleus and nucleolus disappear Centrioles begin forming spindle fibers Prophase Chromosome formation Nucleus and nucleolus disappear Centrioles begin forming spindle fibers Cell Membrane Nucleus Nucleolus

Telophase Nucleus and nucleolus reappear Chromatids uncoil back to chromatin Beginning of cell division Telophase Nucleus and nucleolus reappear Chromatids uncoil back to chromatin Beginning of cell division Anaphase Chromosomes split into chromatids Chromatids move to opposite poles Anaphase Chromosomes split into chromatids Chromatids move to opposite poles Metaphase Chromosomes line up along the equator Metaphase Chromosomes line up along the equator Cytokinesis Complete cell division results in daughter cells that are exactly the same as the original Cytokinesis Complete cell division results in daughter cells that are exactly the same as the original

Mitosis in Plants

Cleavage Furrow & Cell Plate

Control of Cell Size Cell Size (SA/V) Regulatory Checkpoints - Enzymes Cell Size (SA/V) Regulatory Checkpoints - Enzymes

Meiosis

Overview

Meiosis

Genetic Recombination Genetic Recombination: the process that results in chromosomes being arranged in many different ways crossing-over between homologues or chromatids homologous pairs separate independently in meiosis I sister chromatids separate independently in meiosis II Genetic Recombination: the process that results in chromosomes being arranged in many different ways crossing-over between homologues or chromatids homologous pairs separate independently in meiosis I sister chromatids separate independently in meiosis II

CROSSING VERVER

VERVER

Independent Assortment