Cell structure and function

1. Cell structure and function *Show 2 video clips Honors book. Chapters 7.1- 7.2 biology chap7.1-7.2 last updated 9/10/2010

2. Voc Terms 7.1-7.2 Cytoskeleton Centriole Ribosome Endoplasmic reticulum (smooth and Rough) Golgi apparatus Chloroplast Mitochondrion Cell wall Lipid bilayer Selectively permeable • Cell • Cell theory • Cell membrane • Nucleus • Eukaryote • Prokaryote • Cytoplasm • Organelle • Vacuole • Lysosome biology chap4.1

3. What to know: • Name the scientist who first observed living and non living cells. • State the three principles of the cell theory. • Explain why the cell is considered to be the basic unit of life. • Know all cell organelles and functions • Why are cells so small • Explain a fluid mosaic model • Know diff/sim between plant and animal and pro vs euk biology chap4.1

4. Discovery of cells • Cell- is the smallest unit that can carry on all of the processes of life. • 1665, English scientist Robert Hooke used a light microscope to look at cork • Leeuwenhoek- Dutch trader (1632-1723)- first person to look at living cells (protists) biology chap4.1

5. Discovery of cells 150 years after Leeuwenhoek 1838- Matthias Schleiden – plants were composed of cells Theodore Schwann- animal were also made of cells Rudolf Virchow (1821-1902) said all cells come from other cells biology chap4.1

6. Developments in Cell Biology • 1665- Hooke discovers cork cells • 1827- Baer discovers mammalian egg • 1855- Virchow adds to cell theory • 1857- Golgi discovers the Golgi apparatus in the cell • 1996- Scotland researchers clone a sheep from an adult sheep cell • 2004- Tissue engineering used to grow new skin an bone for transplant. biology chap4.1

7. Cell Theory 3 parts: • All living organisms are composed of one or more cells. • Cells are the basic units of structure and function in an organism. • Cells come only from the reproduction of existing cells. biology chap4.1

8. The Cellular Basis of Life All living things share several basic characteristics: • Organized parts- Made of cells • Obtain energy from their surroundings/ Perform chemical reactions (metabolism) 3. Change with time (Evolution) 4. Respond to their environments (Stimuli) 5. Reproduce (asexual and sexual) 6. Made of DNA 7. Regulate internal conditions (Homeostasis) 8. Grow and develop biology chap4.1

9. Cell Diversity • Cells function influences its physical features!! Cell shape: • Cells shape can be simple or complex depending on the function of the cell • Each cell has a shape that has evolved to allow the cell to perform its function effectively biology chap4.1

10. Cell Diversity Cell size: • Size of the cell is limited by the relationship of the cell’s outer surface area to its volume • As the cell grows its volume increases • Smaller the cell the more efficient it is in allowing nutrients and oxygen to pass in and out of the cells biology chap4.1

11. Basic Parts of the Cell 4 common features in all cells • Plasma membrane: or cell membrane, covers a cell’s surface and acts as a barrier between the inside and outside of a cell (in and out) • Cytoplasm: fluid, cytoskeleton, and organelles except cytoplasm - cytosol: cytoplasm that has no membrane bound organelles (20% protein) 3. Coded information in the form of DNA -some float freely inside the cell or -Nucleus: membrane bound organelle that contains a cell’s DNA 4. Ribosomes- makes proteins biology chap4.1

12. 2 Basic types of cells • Prokaryotes- a. lack a membrane bound nucleus and membrane bound organelles b. have DNA is concentrated in the Nucleoid c. have two domains: Archaea and Bacteria 2. Eukaryotes- a. Organisms made up of one or more cells that have a nucleus and membrane-bound organelles b. have a variety of sub cellular structures called organelles c. tend to be much larger than prokaryotes biology chap4.1

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16. Cellular Organization Cells are specialized and unable to survive independently Cells Tissues organs Organ system Muscle cells muscle tissues Heart circulatory system biology chap4.1

17. Cell organelles and features Plasma membrane: - it allows for only certain molecules to enter or leave the cell - it separates internal metabolic reactions from the external environment -excretes waste - interaction with environment biology chap4.1

18. Membrane Lipids Made of phospholipids They have both a polar (hydrophilic) phosphate head and two non polar (hydrophobic) fatty acid tails • Double layer is called phospholipid bilayer Eukaryotes also have lipids called sterols located between the tails of the phospholipids (most common is cholesterol, prevent the membrane from freezing at low temps) biology chap4.1

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20. Membrane Proteins • Integral proteins- specific proteins that are located in the lipid bilayer • Peripheral proteins- located on the outside of the membrane not embedded in it Fluid mosaic model - phospholipid bilayer behaves like a fluid more than it behaves like a solid - Proteins can mover laterally within the bilayer biology chap4.1

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23. Nucleus • Houses and protects genetic information • Chromatin- DNA, long thin fibers • Chromosomes- condensed DNA Nuclear Envelope- double membrane that surrounds the nucleus Nuclear pores- protein-lined holes, passageways for RNA and other materials to enter or exit the nucleus Nucleolus- dense area, where DNA is concentrated and it is making ribosomal RNA Ribosomes- organelles made of protein and protein synthesis in the cytoplasm biology chap4.1

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25. Mitochondria • Tiny organelles that transfer energy from organic molecules to ATP • Powers most of the cell’s chemical reactions • Highly active cells-muscles cells have hundreds of them • Fat storing cells have few • Inner and outer phospholipid membrane • Inner membrane has many folds- cristae, which contain proteins that carry out energy harvesting chemical reactions • Contain own DNA • Can reproduce only by the division of preexisting mitochondria • Originated from prokaryotic cells- symbiotic relationship biology chap4.1

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27. Ribosome • Small, roughly spherical organelles that are responsible for protein synthesis • Do not have a membrane • Made of protein and RNA molecules • Developed in the nucleolus and completed in the cytoplasm • Some float freely in cytosol other in R-ER biology chap4.1

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29. Endoplasmic Reticulum • System of membranous tubes and sacs (cisternae) • Intracellular highway- particles move from one part to another • Amount depends on the cells activity Two types • Rough • Smooth biology chap4.1

30. Rough Endoplasmic Reticulum • Interconnected, flattened sacs covered with ribosomes • Produces phospholipids and proteins • Proteins are exported from the cell- digestive enzymes • Abundant in cells that produce large amounts of protein for export , digestive glands, antibody-producing cells biology chap4.1

31. Smooth ER • Has no ribosomes • Most cells have few S-ER • Builds lipids- cholesterol • Ovaries/testes- produce steroid hormone estrogen and testosterone • Skeletal and heart muscles- release calcium stimulates contraction • Abundant in liver and kidney- detoxify drugs/poisons biology chap4.1

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33. Golgi Apparatus • System, flattened membranous sacs • Packaging system- UPS 1. receive vesicles from ER with new proteins or lipids 2. travel in the Golgi- modify them 3. redirected to various parts of the cell biology chap4.1

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37. Vesicles Can be small, spherically shaped sacs that are surrounded by a single membrane • Lysosomes- vesicles that bud from the Golgi and contain digestive enzymes • Peroxisomes- abundant in liver and kidney (H2O2) • Other-glyoxysomes, endosome, contractile vacuoles • Protein synthesis biology chap4.1

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39. Vesicles cont: 4. Protein synthesis a. proteins are assembled by ribosomes on the rough ER b. Vesicles transport proteins to the golgi apparatus c. the golgi modifies protein and packages them in new vesicles d. vesicles release protein that have destinations outside the cell e. vesicles containing enzymes remain inside the cell as lysosomes, peroxisomes, endosomes biology chap4.1

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41. Cytoskeleton Network of thin tubes and filaments that crisscrosses the cytosol, give it shape • Microtubules- hollow tubes made of protein called tubulin, anchor, shape • Microfilaments- long threads of the beadlike protein actin, double strands • Intermediate filaments- rods that anchor the nucleus, shape of nucleus • Cilia and flagella- hair like structures that extend from the surface of the cell • Centrioles- occur in animal cells , organize for cell division biology chap4.1

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43. Plant cells p 87 Plants have 3 structures that are extremely important to plant function: 1. cell walls 2. large central vacuoles 3.chloroplast Plants are different than animals- plant make their own carbon-containing molecules from the carbon in the environment (photosynthesis) biology chap4.1

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45. Parts: • Cell wall- rigid layer that lies outside the plasma membrane, made of carbohydrates called cellulose • Central vacuole- stores water, metabolic wastes, other materials, 90% of cell, if the cell shrinks the plant wilts • Chloroplast- organelles that have own DNA, have a double membrane a. chloroplast- light energy to make carbs, (thylakoids, chlorophyll) b. chromoplast- colorful pigments biology chap4.1

46. Prokaryotes vs Eukaryotes biology chap4.1

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48. Plant vs Animal biology chap4.1

49. What do all cells have? Common features: 1. 2. 3. 4. biology chap4.1

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