Survey
* Your assessment is very important for improving the workof artificial intelligence, which forms the content of this project
* Your assessment is very important for improving the workof artificial intelligence, which forms the content of this project
Extracellular matrix wikipedia , lookup
Cytokinesis wikipedia , lookup
Tissue engineering wikipedia , lookup
Cell growth wikipedia , lookup
Cell encapsulation wikipedia , lookup
Cell culture wikipedia , lookup
Organ-on-a-chip wikipedia , lookup
Cellular differentiation wikipedia , lookup
THE CELL Anindyaningrum Chrisant Rystiasih Nadia Karlina FT 7 - 2009 The Discovery of Cells I. Robert Hooke (1665), described chambers in cork; called them cells (cellulae) II. Anton van Leeuwenhoek (1665-1675), A. The first to describe living single cells; results were checked and confirmed by Hooke B. Saw “animalcules” in pond water using the scopes that he made III. 1830s - full & widespread importance of cells realized A. Matthias Schleiden,realized that, despite differences in tissue structures, all plant tissues were made of cells & that plant embryos arise from single cell B. Theodor Schwann, realized cellular basis of animal life; concluded that plants & animals are similar structures C. Schwann then proposed first two tenets of Cell Theory 1. All organisms are composed of one or more cells. 2. The cell is the structural unit of life for all organisms. D. Rudolf Virchow, made good case for & added third tenet of Cell Theory derived from his cell division observations; Cells can arise only by division from a preexisting cell. Miller Experiment Replicate conditions of Earth’s Primitive atmosphere •Little/no free oxygen •Mostly CO2 & N2 •Also H2, H2S & CO (PLUS) Energy: Sunlight/ Electrical Discharge (EQUALS) Organic Molecules First cell is presumed to be self replicating RNA in phospholipid membrane. Basic Properties of Cells • I. Life – most basic property of cells; they are the smallest units to exhibit this property • II. Cells are highly complex and organized Each level of structure in cells has a great level of consistency from cell to cell : Organelles have consistent macromolecular composition arranged in a predictable pattern Cell structure is similar from organism to organism despite differences in higher anatomical features • III. Cells possess genetic program & the means to use it (a blueprint); encoded in collection of genes • IV. Cells are capable of producing more of themselves - mitosis and meiosis • V. Cells acquire & use energy (constant input) to develop & maintain complexity – photosynthesis, respiration Source of all energy needed by life on Earth arrives from sun Basic Properties of Cells Contd. • VI. Cells carry out a variety of chemical reactions - sum total of chemical reactions in cells (metabolism); to do this, cells require enzymes (molecules that greatly increase rate of chemical reactions) VII. Cells engage in numerous mechanical activities (require constant energy to keep working): A. Material moved from place to place B. Structures assembled and disassembled C. Cells move from place to place • • VIII. Cells able to respond to stimuli whether organisms are uni- or multi cellular - have receptors that sense environment & initiate responses (move away from object in path or toward nutrient source) • IX. Cells are capable of self-regulation A. Importance of regulatory mechanisms most evident when they break down 1. Failure of cell to correct error in DNA replication -> may lead to debilitating mutation 2. Breakdown in growth control -> may lead to cancer cell & maybe death of whole organism Eukaryotic Animal Cell Eukaryotic Plant Cell Eukaryotic Cell Cycle • • • • M, G1, S, G2 M mitosis (usually followed by cytokinesis) S DNA replication G1 Gap 1 metabolically active and continuously grow • G2 Gap 2 growth continues, protein are synthesis for preparation of mitosis Why are most cells so small? • A. Most eukaryotic cells have single nucleus with only 2 copies of most genes 1. Thus, cells can only produce limited number of mRNAs in a given amount of time 2. The larger a cell's volume, the longer it takes to make the number of mRNAs the cell needs • B. Surface area/volume ratio which affects ability to exchange molecules. Large cell=Small surface area/volume ratio --> surface area is not sufficient to take up substances needed to support metabolism (oxygen, nutrients, etc.) or get rid of wastes • C. Cells depend on diffusion As cell becomes larger, distance from surface to interior gets larger; diffusion time required to move things in & out of a metabolically active cell becomes too long Larger Cells Have Strategies • Increase Surface Area Eg. Intestinal epithelium which absorbs solutes have microvilli . • Decrease cell metabolically active area Eg. interior of large plant cell is typically filled by large, fluid-filled vacuole rather than metabolically active cytoplasm • 4. Giraffe (and other large animal) nerve cells - very long but very small diameter Stem Cells • A cell that divides to produce daughter cells that can either differentiate or remain as stem cells • Source for production of differentiated cells throughout life eg. Blood cells, epithelial cells of skin, epithelial cells of digestive tract (all of which have short life span) Embryonic Stem Cells • Can differentiate into any type of cell Eg. Cell-nuclear replacement or "therapeutic cloning" This is Adult Stem Cell Cell Communication • Direct cell to cell ex: embryonic development, maintainance adult tissue • Indirect – Endocrine signaling (hormone, eg: estrogen) – Paracrine signaling (molecule release on one cell and acts on neighboring target cell, eg: response of vertebrate immune system cells to foreign antigens) Cell Death & Renewal • Apoptosis, programmed cell death • Active Process, maintenance of embryonic development and adult tissues • Apoptotic cells and fragments removes by phagocytosis • Effector: caspases enzyme • Major caspases in Mamalian cells is apoptosome complex (+ cytocrom C from Mytochondria) QUIZ!!! • Please Prepare a Sheet of Paper • We will now test if you have been paying attention. • What is the smallest unit of Living Things? CELL • The Ovum is the largest ……CELL while the CELL smallest is the sperm …. • Organisms are called Multicellular Organisms because they consist of multiple number of…? A. tissues B. organs C. cells • What is a single space in an Excel sheet called? CELL • Fill in the dots: CELL • The longest …… in the human body is the motor neuron cell located in the spinal chord, near the central nervous system. • There are more nerve …..CELL In your brain than stars in the milky way. Reference • http://www.answersingenesis.org/tj/ima ges/v18/i2/abiogenesis_experiment.jpg • Cooper, Geoffrey M. Hausman, Robert E. The Cell. A Molecular Approach. Fourth Edition. Washington, DC. 2007. • easyweb.easynet.co.uk/~sfl/rlb_stem.ht m