1 CELL STRUCTURE AND FUNCTION (Cells : Up Close and Personal)

2 IMPORTANT SCIENTISTS THAT STUDIED CELLS Leeuwenhoek : Invented the microscope Hooke : Looked at cork and named “cells” Schwann : Determined that all animals were made of cells

3 More Important Scientists Schleiden : Determined that all plants are made of cells Virchow : Determined that all cells come from pre-existing cells (cells produce more cells)

4 The Cell Theory 1. All living things are made of cells (Schleiden and Schwann) 2. Cells are the structural and functional units of life 3. All cells come from pre-existing cells (Virchow)

5 Common Cell Structures All cells have the following in common : 1. cytoplasm (internal fluid) 2. cell membrane (not all cells have cell wall) -regulates what enters/exits cell 3. genetic material (DNA or RNA) ; not all cells have a nucleus

6 Why Cells are Small Cells are small because of a surface area–to-volume ratio problem. Cells need a large surface area to allow nutrients and raw materials to enter the cell through the cell membrane and allow wastes to be removed from the cell through the cell membrane. The problem comes from the fact that as an object gets larger, its volume (the interior of the cell) becomes larger faster than the surface area (cell membrane) does. Check out the web site below for a good illustration and a better explanation of this concept.

7 Prokaryotic Cells vs. Eukaryotic Cells Prokaryotic Cells = - cells of bacteria and their relatives - have genetic material but no nucleus - do not have membrane-bound organelles Eukaryotic Cells = - all cells of living things except bacteria - have a nucleus that holds genetic material - have membrane-bound organelles (such as mitochondria, ER, Golgi, chloroplasts, lysosomes, etc.)

8 Prokaryotic & Eukaryotic Cells Diagram

9 Plant Cells Vs. Animal Cells Plant Cells Have : - Plastids (chloroplasts) - Cell Walls (and cell membranes) - Large Vacuole Animal Cells Do Not Have These. Animal Cells Have : - Centrioles (for cell reproduction) - Cell Membrane Only (no cell walls) Plant Cells Do Not Have These.

10 Plant & Animal Cell Diagrams cells/plantcell.html Plant Cell Diagram Animal Cell Diagram

11 Common Organelles of Cells Nucleus = - contains chromosomes for heredity - controls cell’s activities - “brain” of the cell Nucleolus = - inside the nucleus - makes ribosomes Ribosomes = - found either in cytoplasm or on E.R. - sites for protein synthesis

12 Cell Organelles (cont.) Mitochondria = - “powerhouse” of the cell - site for cell respiration (breaking down glucose for energy) Endoplasmic Reticulum (E.R.) = - transportation of materials in cell - “smooth” or “rough” ER Golgi Apparatus = - packaging, modifying, shipping of materials in cell

13 Cell Organelles (cont.) Lysosomes = - contain digestive enzymes - “suicide sacs” Vacuoles = - “bags” containing H2O and dissolved materials (solutes) in the cell Chloroplasts = - sites for photosynthesis in plants - CO2 + H20 Glucose (sugar)

14 Some Cell Types nerve cell sperm cells red blood cells muscle cells cheek cells plant leaf cells potato cells w/ starch plant stem cells

15 Guess What These Are ! Click Here to Find Name Click Here to Find Name Click Here to Find Name Click Here to End Presentation

16 This is a mitochondria !! Click to Return to Pictures Click to End Presentation

17 This is a Chloroplast !! Click to Return to Pictures Click to End Presentation

18 This is a Nucleus !! Click to Return to Pictures Click to End Presentation

19 THE END (This has been an EJ.McM. Presentation)

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