Transcript Cells
Cells By: Lorraine Amoah [Adopted from James Holden & Clint Tucker] The Cell Theory In 1855, a number of scientists put together a theory about cells… 1) All living things are composed of Cells. 2) Cells are the basic unit of structure and function in living things. 3) New cells are produced from existing cells. Who were these scientists? Anton van Leeuwenhoek Dutch businessman One of the first people to use a simple microscope to study nature. 1674 - observed living things in pond water and made detailed drawings of each kind of organism. He called these organisms animalcules. Robert Hooke English physicist 1665 - used one of the first light microscopes to look at thin slices of plant tissues a slice of CORK Called thousands of tiny chambers “cells,” because they reminded him of a monastery’s tiny rooms. this discovery motivated scientists to search for cells in other living things. The Final Three 1838 – Mathias Schlieden found that all Plants are made of cells. 1839 – Theodore Schwann found that Animals are also made up of cells 1855 – Rudolf Virchow found that “Where a cell exists, there must have been a preexisting cell.…” or cells come from cells Basic Cell Structures Cell Membrane – thin, flexible semi permeable membrane around the cell; monitors what enters and exits the cell Nucleus- a large structure that contains the cell’s genetic material and controls the cell’s activities Cytoplasm- material inside the cell membrane—but not including the nucleus The semi-fluid substance that fills the cytoplasm is called the cytosol Test your knowledge… On your study notes, Label these three parts below And the Answer is… Cell Membrane Cytoplasm Nucleus Prokaryote vs. Eukaryote Prokaryote - have cell membranes and cytoplasm but do not contain nuclei. Simple Cells All bacteria are prokaryotes. Eukaryote- Contain nuclei. Also have a cell membrane, cytoplasm, and specialized organelles. Complex Cells All plants, animals, fungi, and many microorganisms, are eukaryotes. Eukaryote cells are much larger than prokaryote cells Test Your Knowledge… Fill in this Venn Diagram using the pictures of prokaryotes/eukaryotes & your Notes Prokaryote Eukaryote And the Answer is… Prokaryote • No nucleus • Simple Cells •Cell Membrane •Cytoplasm • Nucleus • Complex Cells • Specialized Organelles Eukaryote Cell Structure & Organelles Organelles- specialized structure that performs important cellular functions within a eukaryotic cell Cell Structure Cell Walls provide extra support and protection Plants, bacteria, algae, and fungi have Cell Walls * In plants, cell walls are composed of cellulose * Animal Cells DO NOT have CELL WALLS Cytoskeleton Network of protein filaments that helps the cell maintain shape and is involved in cell movement. Contains 2 parts: Microfilaments – long, thin strands that help a cell move and provide a tough framework for the cell Microtubules – hollow tubes by which organelles can move from one part of a cell to another “The Control Center” Nucleus Stores hereditary info in the form of DNA DNA is inside chromatin, a granular material that condenses into chromosomes during cell division Houses a nucleolus – small, dense region within responsible for the assembly of ribosomes Surrounded by a nuclear envelope The Nucleus Centrioles tiny structures located in the cytoplasm of animal cells near the nuclear envelope. Play a role in cell division. Ribosomes Make proteins Made up of rRNA (ribosomal RNA) and protein Can be free-roaming in cytoplasm or located on the Rough Endoplasmic Reticulum Endoplasmic Reticulum Organelle where components of cell membrane are made and proteins are modified Rough E.R. studded with ribosomes Either exports proteins from cell or sends them to the cytoplasm Smooth E.R. No ribosomes Helps in lipid production and breakdown of toxic substances The Endoplasmic Reticulum (E.R.) Golgi Apparatus Vesicles (small transport sacs) carry proteins from Rough E.R. to Golgi for processing/modification. Attaches carbohydrates and lipids to proteins, and the new proteins are “packaged” in new vesicles. Lysosomes Small organelles filled with digestive enzymes They can break down needed materials, used cell parts, pathogens, and even play a role in development They destroy tissue to create fingers because our hands begin as solid structures! Lysosome Animation Who am I? cell organelle that stores materials such as water, salts, proteins, and carbohydrates Vacuole Chloroplasts Found in plants, some algae, and some bacteria Converts the sun’s light energy into chemical energy during photosynthesis Contains chlorophyll (green pigment) Mitochondria cell organelle that releases energy from stored food molecules. Involved in cellular respiration- turning carbohydrates into energy. Cells that need more energy have more mitochondria Other Cell Structures Cilia (cilium): short hair-like projection; produces movement in many cells Cilia Flagella (flagellum): whip-like structure on some cells that is used for movement Flagella Example II: The Cell Factory Factory Part Function Organelle Central Office Manages activities, initiates production, controls activities of factory 1 Assembly Line Assembles raw materials to manufacture items 2 Packaging & Shipping Packs products for distribution 3 Conveyer Belt Moves product within the factory 4 Generator Produces energy for the factory 5 Storage area Stores materials for later use 6 Collection center Breaks down and recycles used parts 7 Door Allows for things to enter and leave the factory 8 Bricks and Steel Construction materials that keep the factory from collapsing 9 Trucks/ 18 Wheelers Move the factory when it needs to relocate 10 Answers: The Cell Factory Factory Part Function Organelle Central Office Manages activities, initiates production, controls activities of factory Nucleus Assembly Line Assembles raw materials to manufacture items Ribosome Packaging & Shipping Packs products for distribution Golgi Bodies Conveyer Belt Moves product within the factory Endoplasmic reticulum Generator Produces energy for the factory Mitochondrion Storage area Stores materials for later use Vacuole Collection center Breaks down and recycles used parts Lysosome Door Allows for things to enter and leave the factory Cell membrane Bricks and Steel Construction materials that keep the factory from collapsing cytoskeleton Trucks/ 18 Wheelers Move the factory when it needs to relocate centrioles So Where did these Eukaryotes come from? Mitochondria and Chloroplasts contain their own DNA genetic information separate from the cells DNA. So, Scientists have done research and come up with a Theory… The ENDOSYMBIONT THEORY Let’s take a look at this evolution… The Endosymbiont Theory The first eukaryotes may have formed from one bacteria engulfing another without killing it. Later a symbiotic relationship was formed Plant Cells Cell wall located outside the cell membrane. Cell wall is made from cellulose fibers, and it is used for support & protection Contains one large vacuole that contains water. Vacuole full = plant is rigid. Vacuole loses water = plant wilts Chloroplasts = contain chlorophyll, which captures sunlight & converts it into energy Plant Cell Build a plant cell Animal Cells Have no cell wall NO chlorophyll CANNOT make their own food So Plant and Animal Cells are… Both eukaryotic cellsBoth have nucleuses, organelles, cell membranes, cytoplasm Plant and animal cell differences Plant Cells Cell wall Chloroplasts Large central vacuole No centrioles Animal Cells Have centrioles No cell wall No chloroplasts No large central vacuole Construct a cell Diversity of Life Unicellular organisms- A single-celled organism Unicellular organisms include both prokaryotes and eukaryotes. Contractile Vacuole A prokaryotic unicellular organism A eukaryotic unicellular organism (paramecium) Diversity of Life Continued… Multicellular organisms- organisms that have more than one cell working together. Have cell specialization Cell specializationspecific roles for different types of cells Levels of Organization Cells- the basic unit of life Tissues- a group of similar cells that perform a particular function Organs- many groups of tissues work together Organ Systems- A group of organs that work together to perform a specific function Organism- An entire living being made up of organ systems Test your Knowledge… ? ? ? Using the following terms, place the levels of organization in the correct order of the chart. -Stomach -Smooth muscle tissue - Digestive System -Muscle Cell ? And the Answer is…