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Cell Structure and Function

Cell Structure and Function. Discovery of Cells. Hooke (1665) Examined cork cells Leeuwenhoek (1674) Observed the first living cells Schleiden (1838) Observed plant cells, discovered the importance of the nucleus. Schwann (1839) Concluded that all living things are made of cells

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Cell Structure and Function

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  1. Cell Structure and Function

  2. Discovery of Cells • Hooke (1665) • Examined cork cells • Leeuwenhoek (1674) • Observed the first living cells • Schleiden (1838) • Observed plant cells, discovered the importance of the nucleus. • Schwann (1839) • Concluded that all living things are made of cells • Virchow (1855) • Proposed that all cells come from other cells • Father of Modern Pathology

  3. Cell Theory • All organisms are made of cells. • All existing cells are produced by other living cells. • The cell is the most basic unit of life.

  4. Cell Types • Prokaryotic • Do not have a nucleus or other membrane-bound organelles. • DNA is suspended in cytoplasm. • All prokaryotes are microscopic single-celled organisms. • ex. bacteria and archaea

  5. Cell Types • Eukaryotes • Have a nucleus and membrane-bound organelles • The nucleus, the largest organelle, encloses the genetic information. • May be multicellular or single-celled organisms.

  6. Movement in Cells • Flagellum • Whip-like structure common in motile protists or gametes. • Cilia • Hair-like organelles located on the exterior of some cells • Pseudopods • “fake-feet”; extensions of cytoplasm, also used to capture prey

  7. Organelles

  8. Nucleus • Control center of the cell • Contains material that forms the genetic code (DNA) • Present in eukaryotic cells • Both plant and animal cells

  9. Parts of the Nucleus • Nucleolus • Involved in cell division and ribosome synthesis • Nuclear membrane (envelope) • Controls what enters and leaves the nucleus • Nucleoplasm • Inside the nuclear membrane (goo) • Chromosome (chromatin) • Carry the code (DNA) that controls the cell

  10. Outside of cell Carbohydrate chains Proteins Cell membrane Inside of cell (cytoplasm) Protein channel Lipid bilayer Cell (plasma) Membrane • Controls substances that enter and leave the cell. • Semi-permeable • Made of a phospholipid bi-layer • Both plant and animal cells

  11. Cytoplasm • Contains a variety of cell structures and dissolved ions • Provides a medium for cell reactions to take place • Matrix between the cell membrane and the nuclear membrane includes protoplasm and organelles • Both plant and animal

  12. Endoplasmic Reticulum • Both plant and animal • Rough Endoplasmic Reticulum (RER) • Has ribosomes on its surface. • Makes proteins for EXPORT • Smooth Endoplasmic Reticulum (SER) • No ribosomes • Makes proteins to be used IN the cell

  13. Ribosomes • Located on the RER and throughout the cytoplasm • Site of protein synthesis • Both plant and animal

  14. Centrioles • Animal cells only • Involved in cell division • Spindle formation • Located near the nucleus

  15. Mitochondria • Site of cellular respiration • Releases energy for the cell in the form of ATP • Has its own DNA passed from mother to child • In both plant and animal cells

  16. Golgi Apparatus • Stores and packages information • It receives proteins made by the endoplasmic reticulum in one end, modifies them, and ships them out the other end. • Cisternae—stacks of membranous sacs • In both plant and animal cells

  17. Lysosome • Found only in animal cells • Packages of digestive enzymes that break down nutrients into smaller chemicals. • Self-destruct mechanism • Will break down food and worn out cell parts • Programmed for cell death • Will “lyse”--break open and recycle cell parts

  18. Vacuole • Stores water and dissolved materials • In plants very large (central vacuole) • In animals small or nonexistant • Contractile vacuole • Some protists can force water out of the vacuole and use it for movement.

  19. Cytoskeleton • Supporting matrix of protein fibers • Maintains cell shape and acts as a scaffold on which organelles are attached • Composed of microfilaments and microtubules • In both plant and animal cells These animal cells are stained to show the cytoskeleton.microtubules (green), microfilaments (red), and nuclei (blue).

  20. Cell Wall • In plants only • Provides shape and support • Made of cellulose • Undigestable carbohydrate, fiber

  21. Chloroplasts • In plants only • Contains chlorophyll • Traps light used in making food (carbohydrate) through the process of photosynthesis

  22. Leucoplasts and Chromoplasts • In plants only • Leucoplasts • Store food such as starch, proteins, and lipids • Chromoplasts • Give color to flowers and leaves

  23. Plant Cells vs. Animal Cells

  24. Onion Epidermal Cells Guard Cells root hair Root Hair Cell Different Kinds of Plant Cells

  25. white blood cell Amoeba red blood cell muscle cell sperm cheek cells nerve cell Paramecium Different Kinds of Animal Cells

  26. Differences between Plant Cells and Animal Cells Animal cells Plant cells Relatively smaller in size Relatively larger in size Irregular shape Regular shape No cell wall Cell wall present

  27. 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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