2nd Quarter Lesson 2 - Reproduction in Living Things PDF

Learning Objectives Identify the stages of mitosis. Understand the role of mitosis to cell growth and repair. Apply knowledge of these concepts to real-life examples.  Cell Division It is a fundamental process to create life, occurring in all forms of it, ensuring the per...

Learning Objectives Identify the stages of mitosis. Understand the role of mitosis to cell growth and repair. Apply knowledge of these concepts to real-life examples.  Cell Division It is a fundamental process to create life, occurring in all forms of it, ensuring the perpetuity of their existence, as well as growth, tissue replacement, and reproduction in multicellular organisms. It is known as cell reproduction or cell division, is the stage in the cell cycle where each cell divides to form two daughter cells. There are three biological mechanisms of cell reproduction: binary fission, meiosis, and mitosis.  Cell reproduction Binary fission Meiosis Mitosis Mitosis  Mitosis When mitosis is completed, It is the most common form 1 2 two genetically identical cells of cell division in somatic are produced. It is a eukaryotic cells (those that will fundamental process during not become sex cells). growth and tissue repair.  Centrosome Interphase The period between two consecutive mitoses is called interphase. As the cell prepares for reproduction, it duplicates its DNA and takes the necessary internal and external measures to successfully undergo the process. A cell divides into two daughter cells that can then divide again, creating a cycle of cell division. Deoxyribonucleic Acid (DNA)  Prophase Centrosome Chromosomes The nuclear envelope starts to break down, gradually dissolving. C hromatin undergoes progressive condensation due to supercoiling, resulting in the formation of chromosomes. The centrosome duplicates, and each one moves to one of the cell's ends, where microtubules are formed. Microtubules Centrosome Microtubules Metaphase The chromosomes align at the cell's equator during metaphase, with the fibers of the mitotic spindle. Microtubules attach to each centromere of the chromosomes. Each chromosome has already duplicated during interphase, so at this point, the two copies separate. Centromere Chromosome  Anaphase Centrosome Chromosome It is the crucial phase of mitosis because it is when the distribution of the original genetic information occurs. The two groups of chromosomes (which are identical) move apart thanks to the microtubules toward opposite poles of the cell. Each set of genetic information concentrates around a centrosome. Microtubules Centrosome Microtubules Telophase The microtubules that aided in the migration of the two groups of chromosomes disappear. The chromosomes start to decondense, exposing the DNA and initiating the processes characteristic of an independent cell. Two new nuclear envelopes begin to form, each containing the information for each new cell. Deoxyribonucleic Acid (DNA)  Cytokinesis Contractile ring It involves the physical separation of the cytoplasm. A contractile ring composed of actin and myosin microfilaments forms, constricting the cell and creating a structure resembling an hourglass. A cleavage furrow forms, ultimately separating the two daughter cells, each with the same number of chromosomes as the parent cell. Mitosis  How does mitosis contributes to healing?  Normal cells divide only when they receive a set of appropriate signals. Normal cells stop dividing when touching other cells. They usually do not migrate to other areas.  Cancer cells divide themselves despite the absence of those signals, and they are resistant to the signals telling them to self-destruct, known as apoptosis or programmed cell death. Cancer cells, on the contrary, invade into surrounding tissues and spread to other organs. Learning Objectives Identify the stages of meiosis. Understand how do the different phases of meiosis contribute to genetic diversity. Determine the importance of genetic diversity for ecosystems. Learning Objectives Define sexual reproduction and its importance in biodiversity. Identify and describe the types of sexual reproduction in plants and animals.  A process that involves the union of sex cells or gametes. Occurs when the sperm fertilizes an egg, producing an offspring that is genetically different from both parents.  The union of male and female gametes to produce a fertilized egg called zygote. FERTILIZATION External Internal External Characterized by the release of both sperm and eggs into an external environment Spawning A process of releasing eggs and sperm into water for the external fertilization to occur External Advantage Can produce large number of offspring. Disadvantage Exposure to environmental hazards will reduce the chance of survival. Internal The egg is fertilized within the female reproductive tract in a process called copulation. Copulation A term used for sexual intercourse or mating. Internal Advantage The fertilized egg is protected from predators and harsh environments Disadvantage Only a limited amount of offspring that is produced. Plant The process of fusion of the female gamete, the ovum or egg and the male gamete produced in the pollen tube by the pollen grain. Pollination The act of transferring pollen grains from the male anther of a flower to the female stigma. Learning Objectives Define asexual reproduction and its importance in various organisms. Identify and describe the different types of asexual reproduction.  Does not involve in the union of gametes. A method wherein an individual produces offspring without the involvement of another individual of the same species. ASEXUAL REPRODUCTION Binary Fission Spore Formation Bud Formation Parthenogenesis Fragmentation Vegetative Propagation Regeneration Binary A method wherein the genetic material of the parent cell is replicated and then followed by the division of the cell into two genetically identical daughter cells. Common among unicellular organisms like bacteria, protozoans, and archaeans. Bud Budding is common in both plants and animals. A new organism is developed from a small part of the parent's body. A bud which is formed detaches to develop into a new organism. Fragmentation Involves the development of new organisms from fragments of the parent organism or the development of new clones of individuals from the whole body that has been fragmented into pieces. Autotomy A term used for self-cutting ability to escape from predators. Regeneration The ability to replace any lost or missing part of the body. Occurs via mitosis n which the organism is capable of regrowing certain body parts. Spore Involves the formation of many spores located in a special structure called sporangium. Fungi, like mushrooms and molds, are examples of organisms that reproduce by forming spores. Parthenogenesis An egg cell can develop into an embryo without fertilization by a sperm. Comes from Greek word parthenos which means “virgin” and genesis which means “origin.” Common among invertebrates like ants, wasps, and bees, and among lower plants. Vegetative Form of asexual reproduction common in plants. A process by which new individuals are formed not from seeds or spores but from other plants. VEGETATIVE PROPAGATION Runner / Stolon Rhizome Bulb Corm Tuber Runner / Stolon A slender stem that grows horizontally along the ground, giving rise to roots and aerial (vertical) branches at specialized points called nodes. Bulb A short underground stem with fleshy leaves called scales. An example of this is an onion. Tuber In this process, new plants grow out of the modified roots called tubers. Sweet potatoes, carrot, cassava and yams are examples of tubers. Rhizome A long, horizontal underground stem with nodes and internodes. An example is ginger. Corm A short, vertical underground stem with nodes and internodes where buds grow and develop into new plants. Examples are taro, cocoyam, and arrowhead. VEGETATIVE PROPAGATION Cutting Layering Grafting Cutting The simplest method of artificial vegetation. A part of the plant is cut off from the mother plant and placed in a new environment where it can grow into another whole plant. Layering One of the easiest method of propagation. A shoot or branch from a parent plant is bent close to the ground, enough to be covered with moist soil. Grafting Most used method of artificial propagation to improve the variety of fruits. A form of regeneration whereas two plants are used to develop a new plant that contains the combined traits of the parent plant.