Biology U4:L5 Exocytosis and Endocytosis PDF

Lesson 4.5 Exocytosis and Endocytosis General Biology 11/2 Science, Technology, Engineering, and Mathematics  Cellular architecture Cellular processes 2 Humans need transportation for their daily living when going to different destinations. 3 Sim...

Lesson 4.5 Exocytosis and Endocytosis General Biology 11/2 Science, Technology, Engineering, and Mathematics  Cellular architecture Cellular processes 2 Humans need transportation for their daily living when going to different destinations. 3 Similarly, the cell also needs a means of their own transport for large molecules. 4 Why is it important to transport large molecules across the membrane? 5 Learning Competency At the end of the lesson, you should be able to do the following: Differentiate exocytosis and endocytosis. (STEM_BIO11/12-Ig-h-14). 6  Learning Objectives At the end of the lesson, you should be able to do the following: Explain the process of transporting large molecules through exocytosis. Describe the mechanism of transporting large molecules through endocytosis. Distinguish the process of phagocytosis, pinocytosis and receptor-mediated endocytosis. 7  Bulk Transport Bulk transport is termed such because it involves transporting bulk or large molecules such as proteins, lipids, nucleic acids, carbohydrates, and other polysaccharides. 8 How does the cell transport large molecules into and out of it? 9 Types of Bulk or Vesicular Transport Exocytosis Types of Phagocytosis Bulk or Vesicular Transport Pinocytosis Receptor-mediated endocytosis 10  Types of Bulk or Vesicular Transport Exocytosis Types of Phagocytosis Vesicular Transport Pinocytosis Receptor-mediated endocytosis 11  Exocytosis This process uses intracellular vesicles and is for hormones, neurotransmitters, digestive enzymes. The Golgi bodies are Molecules from the cell being also involved. transported outside the cell through transport vesicle that fuses with the plasma membrane 12 Exocytosis Constitutive Types of exocytosis Regulated 13 Exocytosis It transports molecules outside the cell through vesicles. This process transports molecules outside the cell then the vesicle fuses with the plasma membrane. Constitutive 14 Exocytosis It transports molecules outside the cell because of triggered signals. In this process, the molecule will be transported outside as a response to the signal for the cell. Regulated 15 How can one distinguish the different forms of endocytosis? 16  Endocytosis The vesicles bud inward and later invaginates to envelope the substances. The vesicles delivers its content. Molecules from the cell being transported into the cell through transport vesicle that buds inward from the plasma membrane 17  Types of Bulk or Vesicular Transport Exocytosis Types of Phagocytosis Vesicular Transport Pinocytosis Receptor-mediated endocytosis 18  Endocytosis Types Function Mechanism This involves engulfing and It functions as a packing through vacuoles Phagocytosis defense and repair for The vacuole fuses with the human body. lysosome and the molecule will be digested. 19  Types of Bulk or Vesicular Transport Exocytosis Types of Phagocytosis Vesicular Transport Pinocytosis Receptor-mediated endocytosis 20 Endocytosis Types Function Mechanism It occurs when vesicles It functions for form around a liquid or Pinocytosis ingestion. around very small particles. 21  Types of Bulk or Vesicular Transport Exocytosis Types of Phagocytosis Vesicular Transport Pinocytosis Receptor-mediated endocytosis 22  Endocytosis Types Function Mechanism It involves the It uses a regulation of molecules receptor protein into the cell. to recognize Receptor-mediated It is involved in the compatible endocytosis uptake, transfer, and molecules which exchange of substances they bring into between cells. the cell. 23  Endocytosis Comparison of the different forms of endocytotic mechanisms in the cell 24 Andy has not been feeling well for the past few days. Her breathing has been heavy and she has been experiencing dizziness. Being overweight, she also finds herself easy to get tired. Upon consulting a doctor, she found out that she has familial hypercholesterolemia which is a genetic disorder. Which type of endocytosis is related to her case? 25 Remember How does exocytosis differ from endocytosis? 26 Remember Exocytosis is a process where molecules EXit the membrane. Endocytosis is a process wherein molecules are ENgulfed by the cell. 27  Check Your Understanding Identify the terms that best suit each of the following descriptions below. 1. It is a process in which an intracellular vesicle fuses with the plasma membrane as secretion occurs. 2. It is a process that is important in transporting proteins like receptors that function in the plasma membrane. 3. This process can happen when a cell receives a signal from outside. 28  Check Your Understanding Explain your answer to the following situations. 1. How are the molecules transported outside the cell through exocytosis? 2. How do molecules get into the cell through endocytosis? 3. What is the function of coated pits? Explain. 29  Let’s Sum It Up! The process of exocytosis forms an intracellular vesicle which fuses with the plasma membrane as secretion occurs. Exocytosis can be of two forms namely constitutive and regulated exocytosis. 30  Let’s Sum It Up! Constitutive exocytosis functions in transporting proteins like receptors that function in the plasma membrane while regulated exocytosis is triggered when a cell receives a signal from outside. 31  Let’s Sum It Up! In the process of endocytosis, cells take in substances by forming vesicles that bud inward around the material. This type of transport can be of three forms namely, phagocytosis, pinocytosis, and receptor-mediated endocytosis. 32  Let’s Sum It Up! In the process of phagocytosis, the cell engulfs the particle by wrapping around extensions called pseudopodia then packs it within a membrane-enclosed sac called vacuoles. 33  Let’s Sum It Up! The process of pinocytosis occurs when vesicles form around a liquid or around very small particles. A form of pinocytosis known as receptor-mediated endocytosis is quite specific because it uses a receptor protein to recognize compatible molecules which they bring into the cell. 34 Let’s Sum It Up! Types of bulk or vesicular transport 35 Challenge Yourself Why do cells that line kidney tubules do not shrink in size even if they ingest substances? 36  Photo Credit Bibliography Hoefnagels, Marielle. Biology: The Essentials. 2nd ed. McGraw-Hill Education, 2016. Mader, Sylvia S., and Michael Windelspecht. Biology. 11th ed. McGraw-Hill Education, 2014. Reece, Jane B, Martha R. Taylor, Eric J. Simon, Jean L. Dickey, Slide 2: Human Cheek Cells by Joseph Elsbernd, is and Kelly Hogan. Biology Concepts and Connections. licensed under CC BY-SA 2.0 via Flickr. 8th ed. Pearson Education South Asia Pte Ltd., 2016. Simon, Eric J., and Jane B. Reece. Campbell Essential Biology. 5th ed. Pearson Education Inc., 2013. Starr, Cecie, Christine A. Evers, and Lisa Starr. Biology Today and Tomorrow. 4th ed. Cengage Learning Asia Pte Ltd, 2014. 37