Presentation on theme: "CELLS An Introduction to. CELL THEORY: One of the 3 Theories that unify all knowledge in Biology 1. All living things are made of one or more cells."— Presentation transcript:
CELLS An Introduction to
CELL THEORY: One of the 3 Theories that unify all knowledge in Biology 1. All living things are made of one or more cells. 2. A cell is the smallest thing that can be considered alive. (1839 Schwann & Schleiden ) Cells were first discovered in 1663 using one of the first primitive microscopes. They were cells in cork. Robert Hooke [The word cell is from Latin 'cellula' which means small compartment ] 3. All cells come from other pre-existing cells by reproduction. (1855 Rudolph Virchow
Microscope 1670’s Anton von Leeuwenhoek – first to observe bacteria and protozoa using a more “advanced” microscope. ~ 1833 Robert Brown reported the discovery of the nucleus
TYPES OF CELLS: A. Prokaryotic 1.SIMPLE a.No nucleus or other complex organelles. b. DNA circular, floating in cytoplasm. 2. TINY :.1 – 10 M m 3. PRIMITIVE: Similar to first living things. Fossils found up to 3.8 billion years old. 4. KINGDOM: Monera (example: bacteria)
TYPES OF CELLS: B. Eukaryotic 1. COMPLEX a.Nucleus + many other complex organelles. b. DNA in nucleus; multiple strands (called chromosomes) 2. LARGE: M m (some up to 2 meters long!) 4. KINGDOMS:all members of Protist, Fungi, Plant, Animal 3.ADVANCED: Evolved almost 2 billion years after Prokaryotes. 5. TYPES: a. PLANTb. ANIMAL
Each cell in an organism has a specific job. Depending on its function it may look very different from the “typical” plant or animal cell.
Notes: HOW EUKARYOTIC CELLS EVOLVED The Endosymbiont Theory (“Endo-” = inside; “Symbiosis” = mutually beneficial relationship) 1. Mitochondria and chloroplasts were once free-living prokaryotic organisms. 2. They entered (or were eaten by!) cells of other organisms and began living there.
3. Helped host cells survive: provided ATP (mitochondria) or glucose (chloroplasts). 4. Host cell provided protection for them. 5. And so - they stayed!
Evidence Supporting Endosymbiont Theory – Mitochondria and Chloroplasts are very much like bacteria: 1.All surrounded by double membranes M m 2. Similar size. a. mitochondria: M m M m b. chloroplasts: M m.5 – 10 M m c. bacteria: 0.5 – 10 M m E Coli (bacteria)Chloroplast Mitochondria
Evidence Supporting Endosymbiont Theory - continued 3. Similar ribosomes. 4. Both have their own DNA (separate from nuclear DNA of the cell) - circular like bacterial DNA. 5. Both reproduce separately from rest of cell - by simple fission, like bacteria.
CELL ANALOGY: A cell is a lot like a town. Its organelles do jobs similar to the functions of some entities in a typical town. Which cell organelle is most like each of the following in terms of the work it does for the cell? 1.Master plan; blueprint. 2.Freeway system 3.Cement factory 4.Food producers (farmers) 5.Power plant, electricity generators. 6. Sewage treatment, waste detoxification 7. Water storage tank 8. Border control, INS 9. Mayor’s office 10. Materials packaging & storage Chromatin (DNA) Endoplasmic Reticulum Ribosome Chloroplast Mitochondria Lysosome Vacuole Cell (plasma) membrane Nucleus Golgi body
What type of cell is this? PLANT CELL
What type of cell is this? ANIMAL CELL
________ are known as the “ power-houses ” of the cell because they produce ATP. MITOCHONDRIA
The cell membrane is also known as the _______ membrane. ________ are the sites where proteins are made ( “ protein synthesis ” ) in the cell. RIBOSOMES PLASMA What structure controls the movement of materials into and out of the cell? CELL MEMBRANE
What is number 6? A vacuole. What is the main thing plant cells store in their vacuoles? WATER
Number 5 is pointing to what? The CELL WALL.
What structures produce glucose and other carbohydrates (i.e. FOOD!)? CHLOROPLASTS
What organelles store primarily enzymes and waste? LYSOSOMES
What is the structure in the nucleus that makes ribosomes and other kinds of RNA? Nucleolus
What is structure number 13? PC diagram CENTRIOLE
What type of cells are these? HUMAN CHEEK CELLS
What type of cells are these? ELODEA CELLS What are the little green things inside them? CHLOROPLASTS
What kind of cells are these? ONION CELLS Onions are plants. Why are there no chloroplasts in these cells? This part of the plant grows underground. Chloroplasts do photosynthesis – that requires light. There’s no point in having chloroplasts in cells that aren’t exposed to light!
Number 6 is pointing to what structure? GOLGI BODY (aka GOLGI APPARATUS, GOLGI COMPLEX)
The two structures found in plant cells that are never found in animal cells are ____________ & ___________. CHLOROPLASTS and CELL WALLS