Introduction to Cells

1. Introduction to Cells

2. Discovery of Cells • The Cell - the basic unit of an organism What piece of scientific equipment do you think needed to be invented before this was possible?… The microscope!

3. The Cell Theory – 3 rules you must know • All organisms are composed of one or more cells. • The cell is the basic unit of structure and organization of organisms. • All cells come from preexisting cells. Viruses are NOT considered living cells Wacky History of Cell Theory

4. Overview of cell types Prokaryotes (no nucleus) Eukaryotes (have nucleus) Plant cell Animal cell

5. Prokaryotes Eukaryotes • Don’t have a nucleus • Don’t have organelles • Are very simple • Oldest form of life Ex: bacteria • Have a nucleus • Have organelles • Are more advanced Ex: plants, animals, fungi, protists

6. Eukaryotes have Organelles • Eukaryotic cells contain a variety of structures inside them called ORGANELLES • Special structures in a cell that each have their own special job. “Little organs”

7. Organelles found in All Eukaryotes Eukaryotes (have nucleus) Plant cell Animal cell

8. Nucleus • Controls the cell’s life processes • Stores genetic material (DNA) • “Control Center” of the cell

9. Cytoplasm • Where all the chemical reactions occur. • A jelly-like substance that the organelles float in

10. Cell Membrane (Plasma Membrane) • Thin barrier that surrounds the cells • Controls transport of materials in and out of the cell • Waste exits cell through the membrane

11. Mitochondria • “Powerhouse” of the cell • Takes food and turns it into energy for the cell (Cellular Respiration)

12. Vacuoles • Stores food, waste, and water • A “storage container” for the cell

13. Ribosome • Makes proteins • Proteins are needed for growth and repair of a cell

14. Lysosome • Breaks down food and old cell parts.

15. Endoplasmic Reticulum (ER) • Packages and ships materials in the cell • “FedEx” of the cell • Makes fats and proteins (in ribosome) Golgi

16. Centrioles • Only found in animal cells and help with cell reproduction

17. Organelles found only in Plants • Cell Wall – firm wall around cell that provides support & protection • Chloroplast – use energy from the sun • to make food (photosynthesis)

18. Summary: Animal vs. Plant cell Animal Cell Plant Cell • Square shape • No centrioles • Large vacuole in • center • Has cell wall • Round shape • Has centrioles

19. See If You Can Answer These… • Which factor contributed most to the development of the cell theory? A) the discovery of many new species during the last century B) the development in advanced techniques to determine the chemical composition of substances C) the increase in knowledge concerning factors influencing the rate of evolution D) the improvement in microscopes and microscopic techniques during the last two centuries 2. Which statement is not part of the cell theory? A) Cells are the structural units in living things B) Cells are the functional units in living things C) New cells arise from preexisting cells D) New cells have nuclei identical to those of preexisting cells 3. Most recently, biologists have increase their knowledge of cell structure and organelles due to the A) discovery of the dissection microscope B) invention of the 40x lens C) invention of the compound light microscope D) development of the electron microscope 4. Which of the following statements is part of the cell theory? A) Only plants are composed of cells B) All cells come from pre-existing cells C) Cells can be produced from nonliving matter

20. Which of the following describes a prokaryotic cell? A) contain membrane bound organelles B) do not have a nucleus C) have a nucleus