Cell Theory & Organelles PDF

Cells At the end of the discussion, you will be able to: 1. Identify different proponents of cell theories; 2. Explain the postulate of the Cell Theory; 3. Describe the structure and the function of major and sub cellular organelles appreciate the importance of the cell and its function. CHARACT...

Cells At the end of the discussion, you will be able to: 1. Identify different proponents of cell theories; 2. Explain the postulate of the Cell Theory; 3. Describe the structure and the function of major and sub cellular organelles appreciate the importance of the cell and its function. CHARACTERISTIC OF LIVING THING What makes a living thing alive? Levels of Biological Organization Every Cell in your Body is totally aware of how you think and feel about yourself -Deepak Chopra What Is Cell? Smallest unit of life that is capable of performing life functions. Building blocks of life THE CELL THEORY What piece of technology made the discovery of cells possible?  ZACHARIAS JANSEN 1597 Dutch lens maker Made the first microscope (simple lens that attached to a tube and an objective)  ANTON VAN LEEUWENHOEK 1670 Father of Microbiology and microscopy Magnifying objects by a factor about 200-300  ANTON VAN LEEUWENHOEK Found motile objects under microscope Looked at pond water under a microscope and was the first to see living cells (Protozoa & Bacteria) First to see red blood cells and human sperm cell Called these creatures “animal cules”  ANTON VAN LEEUWENHOEK Discoveries A rotifer, the Vorticella, a protist Red Blood Cells microscopic organism Leeuwenhoek saw under his microscope. https://www.researchgate.net/figure/Anton-van-Leeuwenhoeks-simple-microscope_fig3_49749832 https://www.discovermagazine.com/planet-earth/leeuwenhoeks-lucky-break  ANTON VAN LEEUWENHOEK Discoveries Discover bacteria by scraping his teeth  ROBERT HOOKE 1665 British biologist English naturalist, architect and polymath coined the term “cells” First observed cells of cork under a very primitive microscope  ROBERT HOOKE The word cell, derived from Latin word cellula or cella meaning “small room/compartment” Named “cells” because they reminded him of the cells that monks live in Cellulae which means the six sided cell of honeycomb  ROBERT HOOKE CELLULAE or CELLA http://commons.wikimedia.org/wiki/Image:RobertHookeMicrographia1665.jpg https://www.bl.uk/collection-items/micrographia-by-robert-hooke-1665  RENE HENRI DUTROCHET 1824 French physiologist Emphasized on the basic processes of living organisms Mechanisms of respiration, light sensitivity & geotropism ( response to gravitation) in plants and osmosis  RENE HENRI DUTROCHET First to recognize the importance of individual cells in the functioning of an organism. Proposed that cell not just a structural unit but also a physiological unit. (1st tenet of cell theory).  1. The cell is the basic unit of life that can perform fundamental functions. CELL THEORY  MATTHIAS SCHLEIDEN 1838 German botanist Discovered that plants were made up of cells  THEODOR SCHWANN 1839 German physician and physiologist Discovered that animals were made up of cells 1st & 2nd Tenet of Cell Theory Cell is the basic unit of life All living things are made up of cell  1. The cell is the basic unit of life that can perform CELL fundamental functions. 2. All known living things THEORY are made up of one or more cells. How does cell come from?  RUDOLF VIRCHOW 1855 German Physician He published Omnis Cellula e cellula It was believed that new cells were created from a fluid called blastema. It was also accepted in the early 1850s that imbalances in blastema caused diseases. Diseases caused changes in a normal cell  RUDOLF VIRCHOW “Cells are the last link in a great chain that forms tissues, organs, systems and individuals. Where a cell exists, there must have been a preexisting cell”. Cells can only arise from pre- existing cells (3rd tenet of Cell theory)  1. The cell is the basic unit of life that can perform CELL fundamental functions. 2. All known living things THEORY are made up of one or more cells. 3. All known living cells arise from pre-existing cells by division  4. The cells contain hereditary information in the form of DNA which can be passed on from the CELL cell. These genetic material must be passed on to the next cells during cell division, THEORY otherwise, organism may not survive. 5. All cells have basic chemical composition. 6. Energy flow occurs within cells.  Cell Theory Timeline 1673 ANTON VAN LEEUWENHOEK Observed living cell 1665 1824 ROBERT HOOKE Henri Dutrochet Discovered Cell Propose cell as physiological unit of life  Cell Theory Timeline 1839 THEODOR SCHWANN Proposed all animal cells are ROBERT REMARK made up of cells 1855 1838 1855 MATTHIAS RUDOLF VIRCHOW SCHLEIDEN Proposed all cells arise from pre Proposed all existing cells plants are made up of cells ORGANELLES  Small organ-like structure present inside the cell. ‘Little organs’ ORGANELLES Specific functions necessary for normal functioning of the cell: hormone & enzyme production to provide energy for the cell. CELL Organelles (The Factory) Front/Main CELL MEMBRANE door of the company Cell Described as fluid membrane mosaic model Composed of proteins, lipid and carbohydrate Phospholipids bilayer Head= hydrophilic Amphiphilic Tail= hydrophobic SELECTIVE PERMEABILITY  CELL FUNCTIONS: MEMBRANE PROTECTIVE: Forms outermost boundary of the cell organelles. DIGESTIVE: Takes in food and excretes waste products. SELECTIVE PERMEABILITY  CELL MEMBRANE FUNCTIONS: Maintain shape & size of cell. Protects internal of the cell. Regulates entry and exit of substances in and out of the cell. Maintain homeostasis. Floor of the company CYTOPLASM Jelly like material formed by 80% of water Present between the plasma membrane and the nucleus Made of 2 parts: cytosol (semi- fluid portion) made of water, soluble compounds, & biomolecules & organelles  CYTOPLASM FUNCTIONS: Supplies the substances required by organelles Medium for metabolic reactions CEO/BOSS of the company NUCLEUSPlural: nuclei Information center of the cell Command center Responsible for carrying the genetic materials in form of chromosomes. They present in all cells except sieve tubes and red blood cells.  NUCLEUS FUNCTIONS: Control all the cell activities like metabolism , growth and cell division Store hereditary information  CELL WALL The WALLS/ SECURITY GATE of a Factory Non organelle Thick layered outside the plasma membrane & rigid structure (Plant CW) Made up of cellulose, fully permeable. (Fungal CW) composed of chitin Maintains the shape of the plant cells Provide mechanical support  CELL WALL FUNCTIONS: Provide definite shape, strength & rigidity Prevents drying up (desiccation) of cells Protects cell from external pathogens The Local POWER PLANT MITOCHONDRIA “POWERHOUSE” of the cell” Filamentous or globular in shape Structure -Length 5-12um -Diameter 0.5-1um FUNCTIONS: Synthesize energy rich compound ATP  The ASSEMBLY ENDOPLASMIC RETICULUM LINES of the FACTORY The word endoplasmic means “within the cytoplasm” & reticulum Latin for “ little net’’ Cisternae ( Latin cisterna, reservoir for a liquid– network of membranous tubules & sacs 2 types: Rough & Smooth ER  Smooth Endoplasmic Reticulum Lacks of ribosomes Stimulates the synthesis of lipids & glycerol (oils &steroids) & transport within the cell Steroids produced (animal cell) are sex hormones of vertebrates & various steroid hormones secreted by adrenal glands Carry put detoxification of drugs and metabolic by products, esp in liver.  Rough Endoplasmic Reticulum (RER) Studded with ribosomes on the outer surface RER transport protein synthesized and packaging by ribosomes to other part of cell E.g certain pancreatic cells synthesize the protein insulin in the ER & secrete hormones into the bloodstream.  The SHIPPING/RECEIVING Department GOLGI COMPLEX Composed of folded sacs like ER Modifies, sorts, pack & transport molecules in the cell. Produce vacuoles and secretory vesicles  The MAINTENANCE CREW LYSOSOME Single membrane vesicles found in animal cells Contain enzymes (hydrolytic enzyme) that help in digesting (hydrolyze) of large molecules (protein, nucleic acid & lipids) Contain enzymes that digest aged or defective cell components or materials taken in by the cell from its environments such as food particles or bacteria LYSOSOME  LYSOSOME Protect cell by destroying foreign invaders like bacteria and viruses. Degradation of worn out organelles in dead cells perform autolysis.  VACUOLE The STORAGE AREA Large vesicles derived from ER and Golgi. Filled wit cell sap, surrounded by semi-permeable membrane called tonoplast. Much larger in plant cell VACUOLE FUNCTIONS: Maintain turgidity of cell in plants Protect plant against herbivores by storing compounds that are poisonous to animals  CHLOROPLAST The SOLAR POWER Rooftop Disc shape organelle contain green pigment chlorophyll Consist of an orderly arrangement of grana within the stroma. Granum contains chlorophyll Site of photosynthesis Trapped light energy and change it into chemical energy  CENTRIOLE The STEERING Wheels of TRUCK A pair of small cylindrical structure (microtubules) “Microtubule-organizing center” Does not exist in plant cell Form spindle fiber for cell division (help organize during the split of the cell) The Air Filters PERIXOSOME Structure: Have a Urate oxidase crystalline core with 32 peroxins (peroximal proteins) that execute peroxisomal functions inside the organelle. contain enzymes that remove hydrogen atoms from various substrates and transfer them to oxygen (O2), producing hydrogen peroxide (H2O2) as a by- product. To rid the body of toxic substances like hydrogen peroxide.  CYTOSKELETON The Building supports This is especially important for animal cells, which lack walls. Organizes the cell structure and activity. Helps to preserve the shape of the cell. It supports the cell & holds everything in place.  FLAGELLA & CILIA EMERGENCY TUNNELS Used for cell movement / help to move the cell out of upcoming danger FLAGELLA CILIA Long & filamentous Short whip like tail appendages (usually many of Long whip like tails for these) movement (usually 1) QUESTIONS?