Cells

1. Cells

2. The Cell Theory • In 1855, a number of scientists put together a theory about cells… • All living things are composed of Cells. • Cells are the basic unit of structure and function in living things. • New cells are produced from existing cells. Who were these scientists?

3. 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.

4. 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.

5. 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

6. 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

7. Test your knowledge… On your study notes, Label these three parts below

8. Prokaryote vs. Eukaryote(simple vs. complex) • Prokaryote - have cell membranes and cytoplasm but do not contain true nucleus. • Simple Cells • All bacteria are prokaryotes. • Have ribosomes • Eukaryote- Contain nucleus enclosed in a nuclear envelope. 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

10. 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 ENDOSYMBIOTIC THEORY Let’s take a look at this evolution…

11. The Endosymbiotic Theory • The first eukaryotes may have formed from one bacteria engulfing another without killing it. • Later a symbiotic relationship was formed

12. Stop and Think… • Are plant and animal cells prokaryotic or eukaryotic? • How does the meaning of prokaryotic or eukaryotic help you answer this question? • Give one or two examples that help you answer this question.

13. 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

14. Plant Cell Build a plant cell

15. Animal Cells • Have no cell wall • NO chlorophyll • CANNOT make their own food

16. So Plant and Animal Cells are… • Both eukaryotic cells- Both have nucleuses, organelles, cell membranes, cytoplasm

17. Plant and animal cell differencesCopy each under the correct picture in your notes 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

18. 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)

19. Diversity of Life Continued… • Multicellular organisms- organisms that have more than one cell working together. Have cell specialization • Cell specialization- specific roles for different types of cells

20. 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

21. Using the following terms, place the levels of organization in the correct order of the chart. -Stomach - Digestive System -Smooth muscle tissue -Muscle Cell Test your Knowledge… ? ? ? ?

22. Cell Structure & Organelles Organelles- specialized structure that performs important cellular functions within a eukaryotic cell

23. 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

24. Centrioles • tiny structures located in the cytoplasm of animal cells near the nuclear envelope. • Play a role in cell division.

25. Chloroplasts • Found in plants, some algae, and some bacteria • Converts the sun’s light energy into chemical energy during photosynthesis • Contains chlorophyll (green pigment)

26. Flagella (flagellum): whip-like structure on some cells that is used for movement Other Cell Structures • Cilia (cilium): short hair-like projection; produces movement in many cells Cilia Flagella

27. Cytoplasm The jelly-like substance that fill the entire cell. The organelles are suspended (floating) in the cytoplasm.

28. 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

29. Endoplasmic Reticulum • Organelle where components of cell membrane are made and proteins are modified (transport) • 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

30. The Endoplasmic Reticulum (E.R.)

31. Golgi Apparatus (bodies) • 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.

32. 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

33. Mitochondria (power house) • 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

34. “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

35. The Nucleus

36. Cell Membrane • Surrounds the cell and provides protection • Also controls what enters and leaves the cell • A flexible barrier • Found in both plant and animal cells

37. Ribosomes • Make proteins • Made up of rRNA (ribosomal RNA) and protein • Can be free-roaming in cytoplasm or located on the Rough Endoplasmic Reticulum

38. Vacuole Found only in plant cells Filled with water Helps makes the cell wall rigid and provides support