Introduction to Cells - Week 3 PDF

The Cell, Cellular Metabolism Reproduction  The objectives of this topics are the following: 1.Describe, completely the anatomy and physiology in a cellular and tissue level approach 2.Label, correctly the different parts and define the functions of the cell 3.Illustrate clear...

The Cell, Cellular Metabolism Reproduction  The objectives of this topics are the following: 1.Describe, completely the anatomy and physiology in a cellular and tissue level approach 2.Label, correctly the different parts and define the functions of the cell 3.Illustrate clearly the normal process of cell division through mitosis and meiosis 4.Exemplify effortlessly the possible resulting diseases and conditions involved in abnormal, cellular division 5.Classify expertly the types of body tissues and its mechanism of repair  Week 3 Topic Outline Cells and Tissues Level of Organization Lecture: PART 1: Introduction to Cells 1.1 Cell theory 1.2 Definitions 1.3 Parts 1.4 Functions 1.5 Transport of substances across the cell membrane PART 2: The Cell cycle 2.1 Mitosis 2.2 Meiosis 2.3 Cellular Diversity 2.4 Cellular Aging 2.5 Pathophysiology of Cell Division 2.6 Changes in cell size and number – cell death PART 3: Tissues 3.1 Types and Origins 3.2 Junctions 3.3 Tissue Regeneration  ICE BREAKER: CELL ANALOGY : Instructions: PA Instructions:RT Instructions: 1) into Divide students Divide smallstudents groups. into small groups. Assign each group a cellular 2) Assign eachcomponent or process group a cellular (e.g. nucleus, component mitochondria, or process cell membrane, (e.g. nucleus, mitosis, mitochondria, cell meiosis). membrane, Give groups a few minutes to brainstorm an analogy for their assigned topic. mitosis, Each group presents their meiosis). analogy to the class, explaining how it relates to the cell component or process. Example: 3) Give groups a few minutes to brainstorm an analogy for their assigned topic. 4) Each group presents their analogy to the class, explaining how it relates to the cell component or Nucleus: The control center of a cell is like the brain of a human. Mitochondria: Theprocess. powerhouses of the cell are like batteries. 1: INCLUDE ICEBREAKER: CELL ANALOGY PART 1: INCLUDE ICEBREAKER: CELL ANALOGY Example: Objective: to foster critical thinking and understanding of cellular components and processes through analogies Nucleus: The control center of a cell is like the brain of a human. Mitochondria: The powerhouses of the cell are like batteries. Instructions: Divide students into Instructions: Divide students into small groups. Assign each group a cellular component or process (e.g. nucleus, mitochondria, cell membrane, mitosis, meiosis). ive groups a few minutes to brainstorm an analogy for their assigned topic.  Cells ✔are the living structural and functional units enclosed by a membrane. ✔ All cells arise from existing cells by the process of cell division, in which one cell divides into two identical cells. ✔ Cell biology or cytology is the study of cellular structure and function. 1 : Cells 1. Cell metabolism and energy use 2. Synthesis of molecules 3. Communication 4. Reproduction and inheritance 1  (2)Types of Animal cell 1. Somatic cell – body cells ex. Blood cell, bone cell, neuron 10 2. Germ cell – sex cells ex. egg cells and sperm cell 11 THREE 1.Plasma Membrane 2.Cytoplasm (3) MAIN – Cytosol – Organelles PARTS OF 3.Nucleus – Chromosomes THE CELL – Genes 1. Plasma Membrane ▪ Barrier ▪ Control ▪ Signaling 2 MEMBRANE STRUCTURE HEAD Consists of a lipid bilayer - made up of phospholipids, TAIL cholesterol and glycolipids. MEMBRANE PROTEINS 1. Integral Protein 2. Peripheral Protein 3. Glycoprotein 4. Glycocalyx MEMBRANE GRADIENTS ACROSS THE PLASMA PERMEABILITY MEMBRANE The plasma membranes are selectively permeable. 1. Concentration gradient is the The cell is either permeable or difference in the concentration of a impermeable to certain substances. chemical between one side of the The lipid bilayer is permeable to plasma membrane and the other. (e.g. small, nonpolar, uncharged Inside and outside the membrane) molecules (e.g. oxygen, carbon dioxide, water and steroids), but 2. Electrical gradient is the difference in impermeable to glucose. concentration of ions between one Transmembrane proteins act as side of the plasma membrane and the channels and transporters to other. assist the entrance of certain substances, for example, 3. Together, these gradients make up an glucose and ion Electrochemical gradient TRANSPORT ACROSS THE PLASMA MEMBRANE 1. Passive Process Passive Process – Diffusion – a substance moves down its concentration Simple diffusion or electrical gradient to cross the membrane using only its own kinetic Channel – Mediated Facilitated energy (energy of motion). diffusion – Kinetic energy is intrinsic to the particles Carrier – Mediated Facilitated that are moving. There is no input of diffusion energy from the cell. – Osmosis Active Process 2. Active Process – Cellular energy is used to drive the – Active Transport substance “uphill” against its – Vesicular Transport concentration or electrical gradient. – The cellular energy used is usually in the form of adenosine triphosphate (ATP). A. Passive Transport – 1. DIFFUSION Molecules move to process wherein solutes moves from an equalize concentration area of high concentration to areas of low concentration. (Tortora & Freudenrich, 2011) PASSIVE PROCESS: DIFFUSION 1. Diffusion – is a passive process in which the random mixing of particles in a solution occurs because of the particles’ kinetic energy. – They move down from higher concentration gradient to a lower conc. gradient. Diffusion is influenced by: ✔Steepness of the concentration gradient ✔Temperature ✔Mass of diffusion substance ✔Surface area ✔Diffusion distance Simple Diffusion – is a passive process in which substances move freely through the lipid bilayer of the plasma membranes of cells without the help of membrane transport proteins. DIFFUSION CHANNEL-MEDIATED FACILITATED DIFFUSION – In channel mediated facilitated diffusion, a solute moves down its concentration gradient across the lipid bilayer through Channel Mediated FD a membrane channel CARRIER-MEDIATED FACILITATED DIFFUSION – In carrier mediated facilitated diffusion, a carrier (also called a transporter) moves a solute down its concentration gradient across the plasma membrane A. Passive Transport Fluid flows from lower solute concentration - – 2. OSMOSIS The net movement of a solvent through a selectively permeable membrane from an area of high concentration to an area of low Often involves movement of water- Into cell – concentration. Out of cell. Tonicity of a solution relates to how the solution influences the shape of body cells. 1. Isotonic Solution 2. Hypotonic Solution 3. Hypertonic Solution 3 A. Passive Transport – 3.FACILITATED Protein binds with molecule DIFFUSION Shape of protein changes Molecule moves across membrane  B. Active Transport – 3. ENDO & EXOCYTOSIS – Solutes are transported across plasma membranes with the use of energy, from an area of lower concentration to an area of higher concentration (e.g. Sodium-potassium pump).  TRANSPORT IN VESICLES Vesicle - a small spherical sac formed by budding off from a membrane Endocytosis - materials move into a cell in a vesicle formed from the plasma membrane – three types: receptor-mediated endocytosis; phagocytosis; bulk-phase endocytosis (pinocytosis) Exocytosis - vesicles fuse with the plasma membrane, releasing their contents into the extracellular fluid. Materials move out in the cell in a vesicles fuse with the plasma membrane. Transcytosis - a combination of endocytosis and exocytosis; vesicles undergo endocytosis on one side of a cell, move across the cell, and then undergo exocytosis on the opposite side. B. Active Transport – 3. ENDOCYTOSIS Plasma membrane surrounds material Edges of membrane meet Membranes fuse to form Receptor-mediated endocytosis vesicle 3  ENDOCYTOSIS Receptor-mediated endocytosis – highly selective type of endocytosis by which cells take up specific ligands. Phagocytosis – a form of endocytosis in which the cell engulfs large solid particles, such as worn- out cells, whole bacteria, or virus. Pinocytosis / Bulk-phase endocytosis – a form of endocytosis in which tiny droplets of extracellular fluid are taken up 2. Cytoplasm and the Organelles 2. Cytoplasm – consists of all the cellular contents between the plasma membrane and the nucleus. Cytosol – the fluid portion of cytoplasm, contains water, dissolved solutes, and suspended particles. Organelles – Little organs, specialized structures inside the cell. (e.g. cytoskeleton, endoplasmic reticulum, ribosomes) CYTOSOL CYTOSKELETON The cytoskeleton is a network of protein filaments that extends throughout The cytosol (intracellular fluid) the cytosol is the fluid portion of the cytoplasm that Microfilaments surrounds organelles and constitutes about 55% of total Intermediate Filaments cell volume Microtubules PROTEIN FILAMENTS Cytosol is 75–90% water plus various dissolved and suspended components. Among these are different Microfilaments – are the thinnest elements of the cytoskeleton. They are types of ions, glucose, amino composed of the proteins actin and myosin and are most prevalent at the edge acids, fatty acids, of a cell. proteins, lipids, ATP, and waste – They help generate movement and provide mechanical support products The cytosol is the site of many Intermediate Filaments - thicker than microfilaments but thinner than chemical reactions required for microtubules a cell’s Microtubules - largest of the cytoskeletal components and are existence long, unbranched hollow tubes composed mainly of the protein tubulin. PARTS OF THE CELL: CENTROSOME The centrosome located near the nucleus, consists of two components: a pair of centrioles and pericentriolar material The two centrioles (are cylindrical structures, each composed of nine clusters of three microtubules (triplets) arranged in a circular pattern Surrounding the centrioles is pericentriolar material, which contains hundreds of ring-shaped complexes composed of the protein tubulin. These tubulin complexes are the organizing centers for growth of the mitotic spindle, which  ENDOPLASMIC RETICULUM RIBOSOMES LYSOSOMES 3. Nucleus 2 Three distinct parts: 1. Nuclear envelope 2. Nucleolus 3. Chromatin carries the genetic material that contains information for cell activities and cell division. Chromosome  tructures of Chromosome Metaphase chromosome Diploid - A cell possessing Centromere region of two copies of each chromosome chromosome Kinetochore (human body cells). Kinetochore microtubules Homologous chromosomes are made up of sister chromatids joined at the centromere. Haploid - A cell possessing a Sister Chromatids single copy of each chromosome (human sex cells). Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.  Cell Division AN INTEGRAL PART OF THE CELL CYCLE. RESULTS IN GENETICALLY IDENTICAL DAUGHTER CELLS. TYPES OF CELL DIVISION 1. Meiosis Also known as reduction division. it is a type of cell division that reduces the number of chromosomes in the parent cell by half and produces four gamete cells (haploid). Occurs only in gametes or sex cells. 1. Mitosis Type of cell division wherein parent cell divides and each of the two daughter cells receives a chromosomal set identical to that of the parent cell (diploid).  Body Cells Mitosis MITO  gametes Sexual reproduction Mitosis ensures that all living organisms will maintain both Genetic Diversity and Genetic Integrity During Meiosis, gamete (sex) cells undergo a “double division”, maintaining the DNA, but reducing the chromosomal count to 23. + Sperm (23) + Egg (23) = Fertilized Cell (46) Meiosis facts CELL CYCLE The cell cycle is a sequence of cell growth and division. The cell cycle is the period from the beginning of one division to the beginning of the next. The time it takes to complete one cell cycle is the generation time.  G1 - Cells undergo majority of growth S - Each chromosome replicates (Synthesizes) to produce sister chromatids Attached at centromere Contains attachment site (kinetochore) G2 - Chromosomes condense - Assemble machinery for division such as centrioles Phases of the Interphase PHASES OF CELL CYCLE 2. M Phase 1. MITOTIC PHASE (DIVIDING PHASE) Prophase 1. Interphase a. Prophase 1st and the longest phase in mitosis. a. G1 phase b. Metaphase Chromatin in the nucleus begins to condense and becomes visible in b. S phase c. Anaphase the light microscope as chromosomes. c. G2 phase d. Telophase – Nucleolus disappears and Nuclear envelope breaks down. Centrosomes begin moving to opposite ends of the cell INTERPHASE and spindle fibers extend from the centromeres. 2. Metaphase 1. G1 phase Alignment of chromosomes into the equatorial region of the cell or in – Usually the longest & most variable the middle. phase of the cycle. The centrosomes are now both in the opposite side of cell with the – Increase in size and synthesize new mitotic spindle fibres extending from them. 2. proteins and organelles in the cell. The mitotic spindle fibres attach to each of the sister chromatids. S phase – 3. Anaphase Characterized by The chromosomes are pulled by the kinetochore microtubules to the poles and form a "V" shape. DNA replication Centromeres split and Sister chromatids separate and migrate to opposite poles. 4. and beginning of centrosome Telophase – duplication. Opposite of Prophase. 5. Cytokinesis Histone synthesis is also observed during this period. The two sets of chromosomes are at the spindle poles and begin results when a fiber ring composed of a protein 3. G2 phase reverting to their decondensed state. called actin around the center of the cell contracts pinching the cell into two daughter cells, each with Proteins required for mitosis Nucleolus and Nuclear membrane starts to re appear. one nucleus. starts to accumulate. Formation of cleavage furrow. Chromatin starts to condensed. The spindle fibers disperse, and cytokinesis will start. QUIZ! 1) What are the 4 functions of the cell? 2) What are the 3 main parts of the cell? 3) Differentiate between passive and active transport. 4) Among the cell organelles, what do you think are the 3 most important? Why? 5) Differentiate mitosis from meiosis.