Philippine Christian University GB1-1STQ-MODULE-Week 3 PDF

Philippine Christian University Sampaloc 1, Dasmariñas City, Cavite 4114 SENIOR HIGH SCHOOL S.Y. 2024-2025...

Philippine Christian University Sampaloc 1, Dasmariñas City, Cavite 4114 SENIOR HIGH SCHOOL S.Y. 2024-2025 MODULE IN GENERAL BIOLOGY 1 (GRADE 11) QUARTER 1 - WEEK 3 (AUGUST 19-23, 2024) LESSON 3: CELL CYCLE AND CELL DIVISION: MITOSIS Overview Have you ever watched a caterpillar turn into a butterfly? If so, you’re probably familiar with the idea of a life cycle. Butterflies go through some fairly spectacular life cycle transitions—turning from something that looks like a worm into a pupa, and finally into a glorious creature that floats on the breeze. Other organisms, from humans to plants to bacteria, also have a life cycle: a series of developmental steps that an individual goes through from the time it is born until the time it reproduces. The cell cycle can be thought of as the life cycle of a cell. In other words, it is the series of growth and development steps a cell undergoes between its “birth”—formation by the division of a mother cell—and reproduction—division to make two new daughter cells. Course Learning Outcome The learner will be able to demonstrate an understanding about the major component of cells and its function and describe the structure and function of the plasma membrane and its role in maintaining homeostasis. Lesson Objectives At the end of this lesson, you are expected to: 1. Characterize the phases of the cell cycle and their control points 2. Describe the stages of mitosis 3. Identify the cell cycle and mitosis with appropriate descriptions for each phase 4. Illustrate the cell cycle and mitosis with appropriate descriptions for each phase 5. Recognize the effects and significance of cell cycle and cell division in life Disclaimer: This module is adapted and modified from the source materials listed in the references list. This is an exclusive property of Philippine Christian University-Dasmariñas SHS and is provided only to enrolled students for their academic use. This module is provided for free by the school through softcopy and/or printed media. Reproduction of this module without official permission is prohibited. 1  Essential Question Why must cells divide? Where do cells get the information they need to function? You may copy and paste the link then enter to the search engine to play video/s: https://www.youtube.com/watch?v=-PfVNZedmGA Test Yourself DIRECTIONS: Locate ten (10) words that are associated to cell division in the puzzle. They can be read horizontally, vertically, or diagonally. E L C Y C E F I L N A C O W B U C I E O T G A M E T E S F I R E F I A G H F I S E L O T M U S G N I P P A O R P I R E V R S I S R T S O O I O U V I A W O W X D D Y N S A Z I T E L U G E N E S E H B L C A C E D O M U F E E E L C Y C L L E C Study these terms Chromatin is an uncoiled mass of genetic material composed of DNA and proteins that condense to form chromosomes. It is composed of small proteins called Histones which help in the coiling of Chromatin so that this very long thread like structure will become a compacted chromosome. Chromosomes are single-stranded groupings of coiled chromatin. Chromatin must exist in chromosomes or coiled form to prevent it from being entangled during cell division which ensures that all the information from the DNA is properly copied and not entangled. Disclaimer: This module is adapted and modified from the source materials listed in the references list. This is an exclusive property of Philippine Christian University-Dasmariñas SHS and is provided only to enrolled students for their academic use. This module is provided for free by the school through softcopy and/or printed media. Reproduction of this module without official permission is prohibited. 2  Chromatid is either of the two strands of a replicated chromosome. Chromatids connected by a centromere are called sister chromatids and has the familiar X shape. Centromere is the point of attachment of between sister chromatid. Within the chromatid, a kinetochore can be found. Kinetochore is the structure where the spindle fiber attaches during cell division. Lesson Proper To divide, a cell must complete several important tasks: it must grow, copy its genetic material (DNA), and physically split into two daughter cells. Cells perform these tasks in an organized, predictable series of steps that make up the cell cycle. The cell cycle is a cycle, rather than a linear pathway, because at the end of each go-round, the two daughter cells can start the exact same process over again from the beginning. In eukaryotic cells, or cells with a nucleus, the stages of the cell cycle are divided into two major phases: interphase and the mitotic (M) phase. During interphase, the cell grows and makes a copy of its DNA. During the mitotic (M) phase, the cell separates its DNA into two sets and divides its cytoplasm, forming two new cells. INTERPHASE Let’s enter the cell cycle just as a cell forms, by division of its mother cell. What must this newborn cell do next if it wants to go on and divide itself? Preparation for division happens in three steps: G 1 phase. also called the first gap phase, the cell grows physically larger, copies organelles, and makes the molecular building blocks it will need in later steps. S phase. the cell synthesizes a complete copy of the DNA in its nucleus. It also duplicates a microtubule- organizing structure called the centrosome. The centrosomes help separate DNA during M phase. G2 phase. During the second gap phase the cell grows more, makes proteins and organelles, and begins to reorganize its contents in preparation for mitosis. MITOTIC phase During the mitotic (M) phase, the cell divides its copied DNA and cytoplasm to make two new cells. M phase involves two distinct division-related processes: mitosis and cytokinesis. In mitosis, the nuclear DNA of the cell condenses into visible chromosomes and is pulled apart by the mitotic spindle, a specialized structure made out of microtubules. Mitosis takes place in four stages: prophase, metaphase, anaphase, and telophase. Prophase: Disclaimer: This module is adapted and modified from the source materials listed in the references list. This is an exclusive property of Philippine Christian University-Dasmariñas SHS and is provided only to enrolled students for their academic use. This module is provided for free by the school through softcopy and/or printed media. Reproduction of this module without official permission is prohibited. 3  The 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. At the end of prophase the membrane around the nucleus in the cell dissolves away releasing the chromosomes. The mitotic spindle, consisting of the microtubules and other proteins, extends across the cell between the centrioles as they move to opposite poles of the cell. Metaphase: The chromosomes line up neatly end-to-end along the center (equator) of the cell. The centrioles are now at opposite poles of the cell with the mitotic spindle fibers extending from them. The mitotic spindle fibers attach to each of the sister chromatids. Anaphase: The sister chromatids are then pulled apart by the mitotic spindle which pulls one chromatid to one pole and the other chromatid to the opposite pole. Telophase: 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. In cytokinesis, the cytoplasm of the cell is split in two, making two new cells. Cytokinesis usually begins just as mitosis is ending, with a little overlap. Importantly, cytokinesis takes place differently in animal and plant cells. Disclaimer: This module is adapted and modified from the source materials listed in the references list. This is an exclusive property of Philippine Christian University-Dasmariñas SHS and is provided only to enrolled students for their academic use. This module is provided for free by the school through softcopy and/or printed media. Reproduction of this module without official permission is prohibited. 4  Summary Mitosis is the process by which a cell replicates its chromosomes and then segregates them, producing two identical nuclei in preparation for cell division. There are 4 major phases, these are the prophase, metaphase, anaphase, and telophase. During mitosis one cell divides once to form two identical cells. The major purpose of mitosis is for growth and to replace worn out cells. If not corrected in time, mistakes made during mitosis can result in changes in the DNA that can potentially lead to genetic conditions. Learning Resources Ruben E. Faltado III. General Biology 1, pages 35-37 Whats Up Dude. (2018, February 8). How do cells divide - phases of mitosis - cell division and the cell cycle - cellular division [Video]. YouTube. https://www.youtube.com/watch?v=-PfVNZedmGA Supplemental Readings and Materials Anna Cherille Morales Ramos, (2017) Exploring Life through Science Series. General Biology 1, pages 41-66 Prepared by: Checked by: Noted by: John Philip C. Angcanan John Philip C. Angcanan Maria Beatriz B. Sico, MM Linneth R. Buenaventura Subject Lead Teacher Science 11 Principal Jemimah T. Sangalang Jan Marie Tabora Subject Teachers Disclaimer: This module is adapted and modified from the source materials listed in the references list. This is an exclusive property of Philippine Christian University-Dasmariñas SHS and is provided only to enrolled students for their academic use. This module is provided for free by the school through softcopy and/or printed media. Reproduction of this module without official permission is prohibited. 5