bio.docx

Describing the Stages of **Mitosis**/**Meiosis Given 2n=6 ** General Biology 1  **STEM\_BIO11/12ld-f-** 7  Describing the Stages of Mitosis/Meiosis Given 2n=6  General Biology 1  **STEM\_BIO11/12ld-f-7 ** **Learning Objectives ** After finishing the module, the learners should be able to: ...

Describing the Stages of **Mitosis**/**Meiosis Given 2n=6 ** General Biology 1  **STEM\_BIO11/12ld-f-** 7  Describing the Stages of Mitosis/Meiosis Given 2n=6  General Biology 1  **STEM\_BIO11/12ld-f-7 ** **Learning Objectives ** After finishing the module, the learners should be able to:    Describe the DNA content of the cell using the terms chromosome, haploid, and diploid;  Compare the different stages of mitosis and meiosis; and  Predict the chromosome content of cells in different phases of meiosis and mitosis.  Describing the Stages of Mitosis/Meiosis Given 2n=6  General Biology 1  **STEM\_BIO11/12ld**-**f-7 ** **Recall ** The cell cycle is the cell\'s life cycle. It has two major stages: the interphase and the mitotic phase. During **mitotic** phase, there are two sub-stages, **Mitosis and Cytokinesis**, which result to two identical daughter cells.  has  Interph  G2 **Phase ** M Phase  **Cytokinesis ** S **Phase ** G, Phase  *Previously, we\'ve discussed the different stages* of *a cell\'s life cycle*. *One of the stages* was Mitosis *where it produces two identical daughter cells. In this lesson*, *we will discuss further what occurs during mitosis and how* mitosis is *different from meiosis. * **FRONTLEARNERS,** INC.  Contains AT&T Natural Voices text to speech technology licensed from Wizzard Speech LLC.  Describing the Stages of Mitosis/Meiosis Given 2n=6  General Biology 1  **STEM\_BIO11/12ld**-**f-7 ** EUKARYOTIC CELLS  HAPLOID CELLS  These are known as gametes or sex cells. They contain only one set of chromosomes from the parent cell.  Haploid cells are produced by meiosis.  Three non-homologous chromosomes  *Before* we *begin let us first define some terms we will be using frequently. Eukaryotic* cells *have two types* of cells, *the haploid cells and the diploid cells Haploid cells are the sex cells that contain only one* set *of chromosomes from the parent cell*.  **FRONTLEARNERS, INC**.  Contains AT&T Natural Voices text to speech technology licensed from Wizzard Speech LLC.  Describing the Stages of Mitosis/Meiosis Given 2n=6  General Biology 1  **STEM\_BIO11/12ld**-**f-7 ** EUKARYOTIC CELLS  DIPLOID CELLS  Cells with two sets of chromosomes are called diploid cells. They  contain homologous pairs of each chromosome in the cell.  Diploid cells reproduce by  mitosis, creating identical copy  of the parent cell.  **Two** pairs **of** homologous chromosomes  *While diploid cells contain two sets* or *the complete set of chromosomes*. *Take note of the difference since we will be discussing the stages of the two types of cell division in terms haploid and diploid cells*.  **FRONTLEARNERS**, **INC**.  Contains AT&T Natural Voices text to speech technology licensed from Wizzard Speech LLC.  General Biology 1  **STEM\_BIO11/12ld-f-7 ** Describing the Stages of Mitosis/Meiosis Given 2n=6  **Definition ** homologous chromosomes  chromosomes with the same sequence of genes  region where the two sister  centromere  chromatids are attached  sister  chromatids  longitudinal half of a chromosome  *Some other terms that will be used in the lesson are homologous chromosomes, chromatids, and centromere. * **FRONTLEARNERS,** INC.  Contains AT&T Natural Voices text to speech technology licensed from Wizzard Speech LLC.  Describing the Stages of Mitosis/Meiosis Given 2n=6  General Biology 1  **STEM\_BIO11/12ld-f-7 ** **Mitosis vs Meiosis ** Mitosis  A process of cell division that **occurs in all eukaryotes** and produces all types **of** cell in the body except sex cells  Cells produced during mitosis  are diploid cells. They are identical to the parent cell.  Meiosis  Meiosis is an eight **stage cell division** process which produces **four haploid** cells as end product.  Meiosis only produce sex cells or gametes which are used for sexual reproduction.  *Mitosis and Meiosis are two types of cell division which occurs in* all *eukaryotic cells*. *Mitosis produces all types of cells present in the body except for the sex cells or gametes which in turn in is produced through meiosis*.  **FRONTLEARNERS,** INC.  Contains AT&T Natural Voices text to speech technology licensed from Wizzard Speech LLC.  Describing the Stages of Mitosis/Meiosis Given 2n=6  DIllustration  Prophase  Stages of Mitosis given 2n=6  X  Metaphase  *Here is an overview of the different stages of Mitosis*.  Anaphase  **REFRONTLEARNERS**, **INC**.  General Biology 1  **STEM\_BIO11/12ld-f-7 ** Telophase  Contains AT&T Natural Voices text to speech technology licensed from Wizzard Speech LLC.  Describing the Stages of Mitosis/Meiosis Given 2n=6  MITOSIS (2n=6)  Prophase  It is the early stage of mitosis where the nucleolus **disappears** and **chromatin fibers** condense into chromosomes. Spindle fibers are then formed **in the** cytoplasm and attaches with the chromosomes.  General Biology **1 ** **STEM\_BIO11/12ld-f-7 ** **Illustration ** Prophase 2n**=6 ** *During prophase stage, the cell* is *preparing for division - the nucleolus disappears, chromosomes are formed and attached with the spindle fibers formed in the cytoplasm*.  **REFRONTLEARNERS, INC**.  Contains AT&T Natural Voices text to speech technology licensed from Wizzard Speech LLC.  Describing the Stages of Mitosis/Meiosis Given 2n=6  MITOSIS (2n=6)  Metaphase  **Chromosomes** align at the \"metaphase  plate**\"** during this phase. Then, **microtubules** from each spindle poles **attach to the chromosomes** in preparation for anaphase.  A spindle checkpoint also occurs  to ensure that the chromatids separate evenly during anaphase.  General Biology 1  **STEM\_BIO11/12ld-f-7 ** **Illustration ** **XXXXX ** Metaphase 2n=6  *The next stage is metaphase where chromosomes align themselves at the metaphase plate and are attached with microtubules from the opposite poles*. *A spindle checkpoint* also *occurs to ensure that the chromatids separate evenly during anaphase. * **FRONTLEARNERS, INC**.  Contains AT&T Natural Voices text to speech technology licensed from Wizzard Speech LLC.  Describing the Stages of Mitosis/Meiosis Given 2n=6  MITOSIS (2n=6)  Anaphase  It is the stage where **separation of chromosomes** occur. The kinetochore  microtubules pull the chromosomes toward the poles - separating the chromatids - while unattached  microtubules push the poles further apart.  **Illustration ** General Biology 1  **STEM\_BIO11/12ld-f-7 ** Anaphase **2n**=6 per pole  *Anaphase is mitosis\' third stage where chromosomes are separated into chromatids once again. * **FRONTLEARNERS, INC**.  Contains AT&T Natural Voices text to speech technology licensed from Wizzard Speech LLC.  Describing the Stages of Mitosis/Meiosis Given 2n=6  MITOSIS (2n=6)  Telophase & Cytokinesis  General Biology **1 ** **STEM\_BIO11/12ld-f-7 ** These are the last stages of mitosis where mitotic spindle is **broken** down and the **nuclear membranes** and **nucleoli ** reappear (telophase). The cytoplasm then divides into **two ** **new cells** during cytokinesis.  へしく  Telophase  **2n=6** per cell  *The* last *stages of mitosis is focused* on *separating the daughter* cells. *When the chromosomes are now enclosed in nucleoli and* nuclear *membrane during* telophase*, cytokinesis then* proceed *in dividing the cell into two diploid cells*.  **FRONTLEARNERS,** INC.  Contains AT&T Natural Voices text to speech technology licensed from Wizzard Speech LLC.  Describing the Stages of Mitosis/Meiosis Given 2n=6  **Illustration ** Stages of Meiosis given 2n=6  Stages of Meiosis I  General Biology 1  **STEM\_BIO11/12ld-f-7 ** prophase I  BE 3E BE  metaphase **I ** anaphase I  telophase I  *The process of meiosis dedicated in producing haploid cells*. *It has two major stages, meiosis I and meiosis II, both* of *which* follows *an extensive process of cell division*.  **FRONTLEARNERS,** INC.  Contains AT&T Natural Voices text to speech technology licensed from Wizzard Speech LLC.  Describing the Stages of Mitosis/Meiosis Given 2n=6  MEIOSIS I (2n=6)  Prophase I  Chromosomes **condense and pair** laterally with their homologous chromosomes during prophase I.  A unique feature of this phase is the occurrence of synapsis (the positioning of the chromosomes for crossing over).  General Biology 1  **STEM\_BIO11/12ld-f-7 ** S  **2n=**6  *Like mitosis*, stages *of meiosis* also follows *the prophase*, *metaphase, anaphase, and* telophase stages. *In Meiosis* I *however, prophase I* is *the pairing of homologous chromosomes. Instead of a single chromosome*, *homologous pairs dominate the entire stages of meiosis I. It* is also *in prophase I where synapsis occurs*, a *feature missing in mitosis*.  **FRONTLEARNERS,** INC.  Contains AT&T Natural Voices text to speech technology licensed from Wizzard Speech LLC.  Describing the Stages of Mitosis/Meiosis Given 2n=6  MEIOSIS **\|** (**2n**=**6**)  Metaphase I  Metaphase I is also where spindle captures chromosome and align them at the metaphase plate.  Unlike in mitosis, **homologue pairs** line up at the metaphase plate and microtubules from opposite poles attach **to only one chromosome** of the homologue pair.  General Biology 1  **STEM\_BIO11/12ld-f-7 ** BE BE BE  2n**=6 ** *Metaphase I in meiosis I* also *occurs with the aligning of chromosomes in the metaphase plate, however*, *instead of single chromosomes lining up, metaphase I has homologous* pairs *of chromosomes lining up at the plate with microtubules from* opposite *poles attaching to them*.  **RFRONTLEARNERS**, **INC**.  Contains AT&T Natural Voices text to speech technology licensed from Wizzard Speech LLC.  Describing the Stages of Mitosis/Meiosis Given 2n=6  MEIOSIS **I** (**2n**=6)  Anaphase I  Chromosomes, at this stage, are pulled to the opposite sides **of** the poles  while keeping the sister chromatids of  each chromosome intact.  Each side of the pole now has 3  chromosomes.  8  General Biology 1  **STEM\_BIO11/12ld**-**f**-**7 ** C  **n=3** per pole  *Up unto this point*, *the cell undergoing meiosis 1* is *a diploid cell with 6 chromosomes in the cell. During Anaphase I however, when the chromosomes are pulled to opposite sides of the poles, each side of the pole has 3 chromosomes only. Keep in mind that anaphase I separates the homologues* pairs *and not the sister chromatids. * **FRONTLEARNERS,** INC.  Contains AT&T Natural Voices text to speech technology licensed from Wizzard Speech LLC.  Describing the Stages of Mitosis/Meiosis Given 2n=6  MEIOSIS **\|** (**2n**=6)  Telophase I & Cytokinesis  Telophase I prepares the cell for the division into daughter cells (cytokinesis) by forming **the nuclear membranes** and nucleoli around the chromosomes.  Two haploid cells (n=3) are then produced after cytokinesis.  General Biology 1  **STEM\_BIO11/12ld-f-7 ** **n=3** per cell  *Telophase I and Cytokinesis finishes the Meiosis I* stage *by enclosing the chromosomes in the nucleolus and nuclear membranes and splitting the* cells *into haploid cells*.  **AFRONTLEARNERS, INC**.  Contains AT&T Natural Voices text to speech technology licensed from Wizzard Speech LLC.  Describing the Stages of Mitosis/Meiosis Given 2n=6  MEIOSIS II **(n=3**)  prophase II  General Biology 1  **STEM\_BIO11/12ld**-**f-7 ** metaphase **II ** anaphase II  telophase II  haploid cell from  Meiosis I  Meiosis II is essentially similar to mitosis. However, the difference is that its starting cell is a haploid cell from meiosis I. Its resulting daughter cells then are four haploid cells.  *Meiosis II* is *essentially similar to mitosis but its starting* cell is *a haploid cell from meiosis I. Its resulting daughter cells are four haploid cells*.  **FRONTLEARNERS,** INC.  Contains AT&T Natural Voices text to speech technology licensed from Wizzard Speech LLC.  Describing the Stages of Mitosis/Meiosis Given 2n=6  **Remember ** General Biology 1  **STEM\_BIO11/12ld**-**f-7 ** **Stages of Mitosis ** **Chromosome ** **Description ** **count (2n=6) ** 1\. Prophase  Chromosomes condense while the nucleolus disappears; mitotic spindles form  2n=6  2\. Metaphase  Chromosomes align at the metaphase plate; microtubules then attaches to each chromosome from opposite poles  2n=6  3\. Anaphase  Microtubules pull sister chromatids from the opposite poles  2n=6 per pole  4\. Telophase  Nucleolus and nuclear membrane reappears; spindle disappears  2n=6 per pole  5\. Cytokinesis  Cells separate into two identical daughter cells  2n=6 per cell  *Remember that the mitotic stage of the cell cycle* follows *five stages which would eventually lead to the formation* of *two new diploid daughter cells*. *Here* is *a* table *summarizing the events occurring at* each *stage*.  **FRONTLEARNERS,** INC**. ** Contains AT&T Natural Voices text to speech technology licensed from Wizzard Speech LLC.  Describing the Stages of Mitosis/Meiosis Given 2n=6  **Remember ** General Biology 1  **STEM\_BIO11/12ld-f-7 ** Stages **of Meiosis ** **Description ** **Chromosome ** **number (2n=6) ** Meiosis I  1\. Prophase I  Homologous chromosomes pair up and exchange fragments  2n=6  2\. Metaphase I  Homologous chromosomes line up at the metaphase plate  2n=6  3\. Anaphase I  Homologue pairs separate into opposite poles  n=3 per pole  4\. Telophase I  Nucleoli reforms  n=3 per pole  5\. Cytokinesis I  Meiosis II  Haploid cells separate  n=3 per cell  Similar to mitotic stages with starting haploid cells from meiosis I  n=3 per cell  *If* mitosis *is for developing diploid cells, meiosis is where sex cells, which necessary* for *sexual reproduction, are produced.* Meiosis *I produces two haploid* cells *while at the end* of *meiosis II, these haploid* cells *are* duplicated *into four haploid cells*. Refer *to the table* for *the summarized changes at each stage* of meiosis.  **FRONTLEARNERS, INC**.  Contains AT&T Natural Voices text to speech technology licensed from Wizzard Speech LLC.