Science 7 Quarter 2 Week 4: Cell Reproduction PDF

Science 7 Quarter 2 Week 4: Cell Reproduction RAY ALDRIN A. PORBULAN SUBJECT TEACHER  Learning Competency 1. recognize that cells reproduce through two types of cell division, mitosis and meiosis, and describe mitosis as cell division for growth...

Science 7 Quarter 2 Week 4: Cell Reproduction RAY ALDRIN A. PORBULAN SUBJECT TEACHER  Learning Competency 1. recognize that cells reproduce through two types of cell division, mitosis and meiosis, and describe mitosis as cell division for growth and repair. Lesson Objectives 1. Identify the types of cell division. 2. Define mitosis and meiosis. 3. Differentiate mitosis and meiosis. 4.Enumerate the significance of mitosis. 5. Describe the different stages of mitosis. 6. Illustrate the stages of mitosis. 7. Summarize the stages that occur during meiosis. Day 1: Two types of cell division Short Review  Animal Cell Nucleus Recall the important Ribosomes organelles involved in the cell cycle process. Cytoplasm Identify the type of cell Endoplasmic Reticulum and its parts and write Cell Membrane your answer in the box provided. Mitochondrion  Plant Cell Nucleus Recall the important organelles involved in Cell Membrane the cell cycle process. Endoplasmic Reticulum Identify the type of cell Cytoplasm and its parts and write Chloroplast your answer in the box provided. Golgi Apparatus Review Activity: Cycle of Life  Question 1. What have you observed in the picture? Can you compare it with yourself during your childhood to your picture now?  Question 2. Which do you think has the greatest number of cells, the adult, the child or they have the same number?  Process Question: Have you experienced to have a wound in your skin? How is the healing process possible? Lesson Purpose Essential Questions: 1. What kind of cell divides by mitosis? 2. What kind of cell divides by meiosis? 3. Where does the mitosis and meiosis division take place? 4. Why are both cell divisions necessary for the development of an organism? 1. What kind of cell divides by mitosis? The cell that divides by mitosis are called somatic cells (non- reproductive cells). Somatic cells are the cells in the body other than sperm and egg cells. 2. What kind of cell divides by meiosis? Sperm Cell The cell that divides by meiosis are called reproductive cells, also known as germ cells or gametes. A gamete is a reproductive cell of an animal or plant. In animals, female gametes are called ova or Egg Cell egg cells, and male gametes are called sperm. 3. Where does the mitosis and meiosis division take place? Mitosis occurs in somatic cells; this means that it takes place in all types of cells that are not involved in the production of gametes. 3. Where does the mitosis and meiosis Testis division take place? (Male) Meiosis occurs in: ❖Testes (male reproductive organ) Ovary (Female) ❖Ovaries (female reproductive organ) 4. Why are both cell divisions necessary for the development of an organism? Mitosis is important because it is essential for growth and development. It is also essential in the maintenance and renewal of cells. 4. Why are both cell divisions necessary for the development of an organism? Meiosis, on the other hand, is essential for gamete formation. Essential Concept Activity Identify the two types of cell division being described in the following: M __ __ E __I __ O __ S __ I __ S 1. It is the division of cells in the reproductive process. M I __ __ __ T O __ S__ __ I S__ 2. It is cell division for growth and repair. Content Area Vocabulary Vocabulary Words Crossing Mitosis Spindle Over Homologous Centrosome Diploid Cell Pair Meiosis Cytokinesis Haploid Cell SUB-TOPIC 1: Stages of Mitosis  Guided Questions: 1. What is mitosis, and why is it important? 2. What are the steps of mitosis, and what happens in each? Guided Questions 1: Mitosis divides a eukaryotic cell’s chromosomes into two identical daughter cells, wherein mitotic cell division produces the cells needed for growth, development, and tissue repair. Guided Question 2: Mitosis is divided into four stages. Day 2: Stages of Mitosis The Cell Cycle Interphase  What is Interphase? Interphase refers to the phase of the cell cycle in which a cell copies its DNA to prepare for mitosis. The Interphase Interphase G1 or Gap 1 Replication of Organelles Phase S or Synthesis DNA Replication Phase G2 or Gap 2 Production of Enzymes needed for Phase Cell Division Prophase  Prophase Prophase is the stage of chromosome replication. The chromosomes condense and the spindle forms; the nucleus disassembles, the nuclear envelope breaks up, and the spindle fibers attach to the chromosomes. Condensation of Chromosomes Spindle Fiber Formation Disassembly of the Nucleus  Nuclear Envelope Disassembles  Attachment of Spindle Fibers to the Chromosomes  It is the step in which the chromosomes formed in prophase move to the middle of the cell. Metaphase These chromosomes line up along the equator of the cell. Movement of Chromosomes to the Metaphase Plate Anaphase This is where the chromosomes separate and move to opposite sides of the cell. Shortening spindle fibers separate the chromosomes.  Movement of Chromosomes to the Opposite Poles of the Cell  The nucleus reforms and a membrane appears between each mass of chromosomes. Telophase This newly formed membrane divides the cytoplasm. Once this is completed, the two separate cells repeat the process. Telophase Mitosis Summary  Day 3: Stages of Meiosis Meiosis I  Prophase I 1.Chromosomes condense and become visible (2𝑛 = 4). 2. Crossing over occurs. 3. Spindle forms. 4. Nuclear envelope breaks up.  What is Crossing Over? Crossing over refers to the exchange of genetic material or chromosome segments between non-sister chromatids in meiosis. This genetic process occurs between homologous regions of matching chromosomes and the interchange of homologous chromosomes.  What are Homologous Chromosomes? Homologous chromosomes are pairs of chromosomes in a diploid organism that have similar genes, although not necessarily identical. There are two main properties of homologous chromosomes: 1) the length of chromosomal arms and 2) the placement of the centromere.  Metaphase I Paired homologous chromosomes line up along the equator of the cell.  Anaphase I Homologous chromosomes separate to opposite poles of the cell. Sister chromatids remain joined.  Telophase I Nuclear envelopes form around chromosomes, which may temporarily decondense. Spindle disappears. Cytokinesis may divide cells into two. Meiosis II  Prophase II Spindles form. Nuclear envelopes break up.  Metaphase II Chromosomes line up along the equator of the cell.  Anaphase II Centromeres split as sister chromatids separate to opposite poles of the cell.  What is a Centromere? Centromere is the point or region on a chromosome to which the spindle attaches during mitosis and meiosis. called also kinetochore.  Telophase II & Cytokinesis Nuclear envelopes assemble around daughter nuclei. Chromosomes decondense. Spindle disappears. Cytokinesis divides cells. Meiosis Summary