Week 7 Grade 11 Biology: Module 7 PDF

MODULE 7 WEEK 7 GRADE 11 BIOLOGY MCA Montessori School, Inc. “MODULE 7 WEEK 7” 1 Meiosis  Meiosis is a type of cell division that reduces the number of chromosomes in the parent cell by half and produces four gamete cells. This process is required to produce egg and sperm cells for...

MODULE 7 WEEK 7 GRADE 11 BIOLOGY MCA Montessori School, Inc. “MODULE 7 WEEK 7” 1 Meiosis  Meiosis is a type of cell division that reduces the number of chromosomes in the parent cell by half and produces four gamete cells. This process is required to produce egg and sperm cells for sexual reproduction. It begins with a parent cell that is diploid (23 pairs of chromosomes), meaning it has two copies of each chromosome. The parent cell undergoes one round of DNA replication followed by two separate cycles of nuclear division. The process results in four daughter cells that are haploid, which means they contain half the number of chromosomes of the diploid parent cell. For educational purposes o MEIOSIS I 1.Interphase The DNA in the cell is copied resulting in two identical full sets of chromosomes. Outside of the nucleus are two centrosomes, each containing a pair of centrioles, these structures are critical for the process of cell division http://www.phschool.com/science/biology_place/bio During interphase, coach/meiosis/premei.html microtubules extend from these centrosomes. For educational purposes o 2. Prophase I The copied chromosomes condense into X-shaped structures that can be easily seen under a microscope. Each chromosome is composed of two sister chromatids containing identical genetic information. The chromosomes pair up so that both copies of chromosome 1 are together, both copies of chromosome 2 are together, and so on. The pairs of chromosomes may then exchange bits of DNA in a process called http://www.phschool.com/science/biology_place/biocoach/meiosis /proi.html recombination or For educational purposes o 3. Metaphase I The chromosome pairs line up next to each other along the center (equator) of the cell. The centrioles are now at opposite poles of the cell with the meiotic spindles extending from them. The meiotic spindle fibers attach to one chromosome of each pair. http://www.phschool.com/science/biology_place/biocoach/meiosis /metai.html For educational purposes o 4. Anaphase I The pair of chromosomes are then pulled apart by the meiotic spindle, which pulls one chromosome to one pole of the cell and the other chromosome to the opposite pole. In meiosis I, the sister chromatids stay together. This is different to what happens in mitosis and meiosis II. http://www.phschool.com/science/biology_place/biocoach/ meiosis/anai.html For educational purposes o 5. Telophase I and cytokinesis The chromosomes complete their move to the opposite poles of the cell. At each pole of the cell, a full set of chromosomes gather together. A membrane forms around each set of chromosomes to create two new nuclei. The single cell then pinches in the middle to form two separate daughter cells each containing a full set of chromosomes within a nucleus. This process is known as cytokinesis. http://www.phschool.com/science/biology_place/biocoach/meiosis/teloi.html For educational purposes o MEIOSIS II 6. Prophase II Now there are two daughter cells, each with 23 chromosomes ( 23 pairs of chromatids) In each of the two daughter cells the chromosomes condense again into the visible X- shaped structures that can be easily seen The under a microscope. membrane around the nucleus in each daughter cell dissolves away releasing the chromosomes. The centrioles duplicate. The meiotic spindle forms again. http://www.phschool.com/science/biology_place/biocoach/meiosis For educational purposes o 7. Metaphase II In each of the two daughter cells the chromosomes (pair of sister chromatids) line up end-to-end along the equator of the cell. The centrioles are now at opposite poles in each of the daughter cells. Meiotic spindle fibers at each pole of the cell attach to each of the sister chromatids. http://www.phschool.com/science/biology_place/biocoach/meiosis/metaii.html For educational purposes o 8. Anaphase II The sister chromatids are then pulled to opposite poles due to the action of the meiotic spindle. The separated chromatids are now individual chromosomes. http://www.phschool.com/science/biology_place/biocoach/meiosis /anaii.html For educational purposes o 8. Telophase II and cytokinesis The chromosomes complete their move to the opposite poles of the cell. At each pole of the cell a full set of chromosomes gather together. A membrane forms around each set of chromosomes to create two new cell nuclei. This is the last phase of meiosis, however, cell division is not complete without another round of cytokinesis. Once cytokinesis is complete, there are four grand daughter cells, each with half a set of chromosomes (haploid). http://www.phschool.com/science/biology_place/biocoach/meiosis/teloii.html For educational purposes o  Worksheet 6 Do pp. 65-66. You may search the net to answer this activity. For educational purposes o For educational purposes o QUIZ #2 Sources: Cadsi, R.D, Gambulao, G., San Luis, AM.O., Bantic, L.P (2016). Biology 1. St. Andrew Publishing House. https://giphy.com/gifs/pRIf2kRCgJsHe/html5 https://www.newscientist.com/term/dna/ http://www.phschool.com/science/biology_place/biocoach/meiosis/premei.html https://www.youtube.com/watch?v=c5hA0WCv1lg Thank you!!! GRADE 11 BIOLOGY MCA Montessori School, Inc. “MODULE 7 WEEK 7” 17