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HOMEOSTASIS

HOMEOSTASIS. Understanding Homeostasis at the Cellular Level. CELL THEORY AND STRUCTURE. C ell T heory. All living things are made of cells Cells are the basic unit of structure and function in an organism (basic unit of life)

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HOMEOSTASIS

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  1. HOMEOSTASIS

  2. Understanding Homeostasis at the Cellular Level CELL THEORY AND STRUCTURE

  3. Cell Theory • All living things are made of cells • Cells are the basic unit of structure and function in an organism (basic unit of life) • Cells come from the reproduction of existing cells (cell division)

  4. History of Cells & the Cell Theory • In 1665, Robert Hooke used a microscope to examine a thin slice of cork (dead plant cell walls) • What he saw looked like small boxes • Hooke is responsible for naming cells • In 1673, Leeuwenhoek was first to view living organisms • Leeuwenhoek used a simple, handheld microscope to view pond water & scrapings from his teeth

  5. SCHLEIDEN, SCHWANN & VIRCHOW • In 1838, a German botanist named Matthias Schleidenconcluded that all plants were made of cells • In 1839, a German zoologist named Theodore Schwannconcluded that all animals were made of cells • In 1855, a German medical doctor named Rudolph Virchow observed, under the microscope, cells dividing • He reasoned that all cells come from other pre-existing cells by cell division

  6. Remember Endosymbiotic Theory • In 1970, American biologist, Lynn Margulis, provided evidence that some organelles within cells were at one time free living cells themselves – this is called Endosymbiotic Theory • Chloroplasts and mitochondria were the organelles she pointed to as evidence of this theory • Chloroplast and Mitochondria have their own DNA which is different from the DNA of the cell

  7. Number of Cells • Unicellular – composed of one cell • Ex: bacteria, yeast • Multicellular - composed of many cells that may organize • Ex: butterfly, flower

  8. Prokaryotes • Have a nucleoid region contains the DNA (no nucleus) • Have a cell membrane & cell wall • Contain ribosomes to make proteins in their cytoplasm

  9. Eukaryotic Cell Contain 3 basic cell structures: • Nucleus (containing DNA) • Cell Membrane • Cytoplasm with organelles

  10. Two Main Types of Eukaryotic Cells Plant Cell Animal Cell

  11. Organelles • Called the “organs” of cells • Very small in size • Have specific functions • Found in cytoplasm of cell

  12. Lysosome • Contain digestive enzymes • Break down food and worn out cell parts

  13. Nucleolus • Inside nucleus • Produces the ribosomes that make proteins

  14. Smooth & Rough Endoplasmic Reticulum • Smooth ER - lacks ribosomes & detoxifies poisons and synthesizes lipids • Rough ER - has ribosomes on its surface & makes proteins to EXPORT

  15. Mitochondria • Site of Cellular respiration – the capturing of energy from food • Breaks down glucose to produce energy ATP

  16. Chloroplast Plant Cell Organelles • Process called photosynthesis occurs here

  17. Cell wall Plant Cell • Made of cellulose • Found in plant cells

  18. Vacuole Plant Cell Organelles • Have a large central vacuole

  19. Animal Cell Organelles • Glycogen is stored in the cytoplasm of animal cells for food energy glycogen granule

  20. Animal Cell Organelles • Near the nucleus in an animal cell • Help cell divide

  21. What are the basic parts of all eukaryotic cells? Have a cell membrane surrounding the cytoplasm Have membrane-bound organelles Have a nucleus

  22. Differences between plant cells and animal cells Animal cells Plant cells Relatively small in size Relatively large in size Irregular shape Regular shape No cell wall Cell wall present

  23. Differences between Plant Cells and Animal Cells Animal cells Plant cells Vacuole small or absent Large central vacuole Glycogen as food storage Starch as food storage Nucleus at the center Nucleus near cell wall

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