The Cellular Level of Organization PDF

Anatomy & Physiology The Cellular Level of Organization Instructor: Peter M. Maintang Introduction The purpose of this discussion is to: 1. Introduce the parts of a cell. 2. Discuss the importance of the plasma membrane....

Anatomy & Physiology The Cellular Level of Organization Instructor: Peter M. Maintang Introduction The purpose of this discussion is to: 1. Introduce the parts of a cell. 2. Discuss the importance of the plasma membrane. 3. Discuss the components of the cytoplasm. 4. Compare and contrast mitosis and meiosis. 5. Understand the effects aging has on the cell. Copyright © 2014 John Wiley & Sons, Inc. All rights reserved. Parts of a Cell The cell can be subdivided into 3 parts: 1. Plasma (cell) membrane 2. Cytoplasm § Cytosol § Organelles 3. Nucleus § Chromosomes § Genes Copyright © 2014 John Wiley & Sons, Inc. All rights reserved. Parts of a Cell Copyright © 2014 John Wiley & Sons, Inc. All rights reserved. The Plasma Membrane The plasma membrane is a flexible yet sturdy barrier that surrounds and contains the cytoplasm of the cell. Copyright © 2014 John Wiley & Sons, Inc. All rights reserved. Membrane Proteins Two types of membrane proteins are § Integral (also called transmembrane) proteins § Peripheral proteins Copyright © 2014 John Wiley & Sons, Inc. All rights reserved. Functions of Membrane Proteins § Membrane proteins can serve a variety of functions. § The different proteins help determine many of the functions of the cell membrane. Copyright © 2014 John Wiley & Sons, Inc. All rights reserved. Membrane Fluidity Membranes are fluid structures because most of the membrane lipids and many of the membrane proteins move easily in the bilayer. § Membrane lipids and proteins are mobile in their own half of the bilayer. Cholesterol serves to stabilize the membrane and reduce membrane fluidity. Copyright © 2014 John Wiley & Sons, Inc. All rights reserved. Membrane Permeability Plasma membranes are selectively permeable. § The lipid bilayer is always permeable to small, nonpolar, uncharged molecules. § Transmembrane proteins that act as channels or transporters increase the permeability of the membrane. § Macromolecules are only able to pass through the plasma membrane by vesicular transport. Copyright © 2014 John Wiley & Sons, Inc. All rights reserved. Gradients Across the Plasma Membrane A concentration gradient is the difference in the concentration of a chemical between one side of the plasma membrane and the other. An electrical gradient is the difference in concentration of ions between one side of the plasma membrane and the other. Together, these gradients make up an electrochemical gradient. Copyright © 2014 John Wiley & Sons, Inc. All rights reserved. Transport Across the Plasma Membrane Transport processes that move substances across the cell membrane are: § Passive processes § Simple diffusion § Facilitated diffusion § Osmosis § Active processes § Active transport § Vesicular transport Copyright © 2014 John Wiley & Sons, Inc. All rights reserved. Passive Processes Copyright © 2014 John Wiley & Sons, Inc. All rights reserved. Simple Diffusion Diffusion is influenced by: 1. Steepness of the concentration gradient 2. Temperature 3. Mass of diffusion substance 4. Surface area 5. Diffusion distance Copyright © 2014 John Wiley & Sons, Inc. All rights reserved. Facilitated Diffusion Transmembrane proteins help solutes that are too polar or too highly charged move through the lipid bilayer. The processes involved are: § Channel mediated facilitated diffusion § Carrier mediated facilitated diffusion Copyright © 2014 John Wiley & Sons, Inc. All rights reserved. Channel Mediated Facilitated Diffusion Copyright © 2014 John Wiley & Sons, Inc. All rights reserved. Carrier Mediated Facilitated Diffusion Copyright © 2014 John Wiley & Sons, Inc. All rights reserved. Diffusion: A Comparison Copyright © 2014 John Wiley & Sons, Inc. All rights reserved. Osmosis The net movement of a solvent through a selectively permeable membrane from an area of high concentration to an area of low concentration. Copyright © 2014 John Wiley & Sons, Inc. All rights reserved. Tonicity Tonicity of a solution relates to how the solution influences the shape of body cells. Copyright © 2014 John Wiley & Sons, Inc. All rights reserved.  Active Processes Copyright © 2014 John Wiley & Sons, Inc. All rights reserved. Primary Active Transport Energy derived from ATP changes the shape of a transporter protein which pumps a substance across a plasma membrane against its concentration gradient. Copyright © 2014 John Wiley & Sons, Inc. All rights reserved. Secondary Active Transport Energy stored (in a hydrogen or sodium concentration gradient) is used to drive other substances against their own concentration gradients. Copyright © 2014 John Wiley & Sons, Inc. All rights reserved. Active Transport in Vesicles: Receptor- mediated Endocytosis Copyright © 2014 John Wiley & Sons, Inc. All rights reserved. Active Transport in Vesicles: Phagocytosis Copyright © 2014 John Wiley & Sons, Inc. All rights reserved. Active Transport in Vesicles: Bulk Phase Endocytosis (Pinocytosis) Copyright © 2014 John Wiley & Sons, Inc. All rights reserved. Active Transport in Vesicles: Exocytosis & Transcytosis Exocytosis – membrane-enclosed secretory vesicles fuse with the plasma membrane and release their contents into the extracellular fluid. Transcytosis – a combination of endocytosis and exocytosis used to move substances from one side of a cell, across it, and out the other side. Copyright © 2014 John Wiley & Sons, Inc. All rights reserved. A Comparison of Transport Types Copyright © 2014 John Wiley & Sons, Inc. All rights reserved. A Comparison of Transport Types Copyright © 2014 John Wiley & Sons, Inc. All rights reserved. Parts of a Cell: Cytoplasm Copyright © 2014 John Wiley & Sons, Inc. All rights reserved. Cytoplasm Cytosol is also known as the intracellular fluid portion of the cytoplasm. Organelles are the specialized structures that have specific shapes and perform specific functions. Copyright © 2014 John Wiley & Sons, Inc. All rights reserved. Copyright © 2014 John Wiley & Sons, Inc. All rights reserved. Copyright © 2014 John Wiley & Sons, Inc. All rights reserved. Cytoskeleton Copyright © 2014 John Wiley & Sons, Inc. All rights reserved. Centrosome/Centrioles Copyright © 2014 John Wiley & Sons, Inc. All rights reserved. Cilia and Flagella Copyright © 2014 John Wiley & Sons, Inc. All rights reserved. Cilia and Flagella Copyright © 2014 John Wiley & Sons, Inc. All rights reserved. Ribosomes Copyright © 2014 John Wiley & Sons, Inc. All rights reserved. Endoplasmic Reticulum Copyright © 2014 John Wiley & Sons, Inc. All rights reserved. Golgi Complex Copyright © 2014 John Wiley & Sons, Inc. All rights reserved. Copyright © 2014 John Wiley & Sons, Inc. All rights reserved. Lysosomes Copyright © 2014 John Wiley & Sons, Inc. All rights reserved. Peroxisomes Peroxisomes are structures that are similar in shape to lysosomes, but are smaller and contain enzymes that use oxygen to oxidize (break down) organic substances. Copyright © 2014 John Wiley & Sons, Inc. All rights reserved. Proteasomes Proteasomes are barrel-shaped structures that destroy unneeded, damaged, or faulty proteins by cutting long proteins into smaller peptides. Copyright © 2014 John Wiley & Sons, Inc. All rights reserved. Mitochondria Copyright © 2014 John Wiley & Sons, Inc. All rights reserved. Nucleus Copyright © 2014 John Wiley & Sons, Inc. All rights reserved. Nucleus The nucleus contains the cell’s hereditary units, called genes, which are arranged in chromosomes. Copyright © 2014 John Wiley & Sons, Inc. All rights reserved. Gene Expression Copyright © 2014 John Wiley & Sons, Inc. All rights reserved. Protein Synthesis: Transcription Transcription occurs in the nucleus and is the process by which genetic information encoded in DNA is copied onto a strand of RNA to direct protein synthesis. Copyright © 2014 John Wiley & Sons, Inc. All rights reserved. Protein Synthesis: Translation Translation occurs in the ribosome and is the process of reading the mRNA nucleotide sequence to determine the amino acid sequence of the newly formed protein. Copyright © 2014 John Wiley & Sons, Inc. All rights reserved. Protein Synthesis During Translation Copyright © 2014 John Wiley & Sons, Inc. All rights reserved. Cell Division Cell division is a process by which cells reproduce themselves. § Cell cycle Copyright © 2014 John Wiley & Sons, Inc. All rights reserved. Interphase G1 phase S G2 phase Copyright © 2014 John Wiley & Sons, Inc. All rights reserved. Mitotic Phase: Prophase During prophase chromatin condenses into chromosomes. Copyright © 2014 John Wiley & Sons, Inc. All rights reserved. Mitotic Phase: Metaphase During metaphase centromeres of chromosomes line up at the metaphase plate. Copyright © 2014 John Wiley & Sons, Inc. All rights reserved. Mitotic Phase: Anaphase During anaphase centromeres of chromosomes split and sister chromatids move toward opposite poles of the cell. Copyright © 2014 John Wiley & Sons, Inc. All rights reserved. Mitotic Phase: Telophase During telophase the mitotic spindle dissolves, chromosomes regain their chromatin appearance, and a new nuclear membrane forms. Copyright © 2014 John Wiley & Sons, Inc. All rights reserved. Cytokinesis During cytokinesis a cleavage furrow forms and eventually the cytoplasm of the parent cell fully splits. § When this is complete, interphase begins. Copyright © 2014 John Wiley & Sons, Inc. All rights reserved. Copyright © 2014 John Wiley & Sons, Inc. All rights reserved. Control of Cell Destiny 3 possible destinies: 1. Remain alive and functioning without dividing. 2. Grow and divide. 3. Die. Copyright © 2014 John Wiley & Sons, Inc. All rights reserved. Reproductive Cell Division: Meiosis I Copyright © 2014 John Wiley & Sons, Inc. All rights reserved. Reproductive Cell Division: Meiosis II Copyright © 2014 John Wiley & Sons, Inc. All rights reserved. Cellular Diversity Copyright © 2014 John Wiley & Sons, Inc. All rights reserved. Aging and Cells As we age: § Our cells gradually deteriorate in their ability function normally and in their ability to respond to environmental stresses. § The numbers of our body cells decreases. § We lose the integrity of the extracellular components of our tissues. Free radicals Copyright © 2014 John Wiley & Sons, Inc. All rights reserved. References: Tortora, G. (2017). Tortora’s Principles of Anatomy and Physiology. Global edition. Marieb, E. (2016). Essential of Human anatomy and physiology. 11th Edition. Singapore: Pearson education South Asia. VanPutte, C. (2016). Seeley's Essentials of Anatomy & Physiology. 9th Ed. New York: McGraw-Hill Education. Rizzo, D. (2016). Fundamentals of Anatomy and Physiology. 4th Edition. Andover: Cengage Learning. Resources for OpenStax. Physiology and pathology. Attributions provided by Creative Commons. https://openstaxcollege.org/textbooks/physiology/adapt Copyright © 2014 John Wiley & Sons, Inc. All rights reserved.