CELL (PLASMA) MEMBRANE

Transcription

1 CELL (PLASMA) MEMBRANE Separates cell from its environment Controls substances that enter and leave the cell Selectively permeable allows certain substances to pass

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3 COMPOSITION Composed of 2 layers of phospholipids 2 fatty acids + glycerol + phosphate group Also contains steroids &cholesterol Proteins attached to the surface (peripheral) or embedded in the phospholipid layer (integral)

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6 ORGANELLES Structures in the cytoplasm that perform specific functions Cytoplasm is gel-like material that fills the cell and supports the organelles Because it is always moving, known as cytoplasmic streaming the cytoplasm aids in moving materials around the cell

7 1. MITOCHONDRIA Powerhouse Site of energy transfer between organic compounds Energy is stored in the form of ATP adenosine triphosphate More abundant in active cells such as liver and muscle cells Inner folded membrane called cristae- creates more surface area for chemical reactions to takes place breakdown of ATP

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9 2. RIBOSOMES protein factories Most numerous organelles Composed of proteins & RNA Can be located freely in the cytoplasm where proteins that will be used by the cell Can be on the endoplasmic reticulum where proteins will leave the cell

10 3. ENDOPLASMIC RETICULUM System of tubes & sacs that transport materials throughout the cell A. Rough ER studded with ribosomes; proteins are exported from the cell B. Smooth ER lacks ribosomes; produces steroids, regulates calcium, breaksdown toxins

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12 4. GOLGI APPARATUS Series of flattened sacs Processes, packages & secretes proteins that leave the cell Packages proteins in a vesicle

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15 5. LYSOSOME Sac - like organelle containing enzymes Digests proteins, carbs, lipids, DNA & RNA, old organelles & pathogens (bacteria or virus)

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17 6. CYTOSKELETON Maintains shape & framework of the cell Composed of: Microfilaments threads of protein called actin that aid in cell movement Microtubules hollow tubes that support the cell membrane & aid in cell division

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19 7. Cilia Bundles of microtubules Hair-like structures on the outer surface Move unicellular organism (ex. Paramecium) Sweep materials through multicellular organisms (ex. Line human respiratory tract)

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21 8. Flagella Bundles of microtubules Long, whip like extensions Propel organisms or the cell Ex. Sperm cells

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23 9. CENTRIOLES Bundles of microtubules Separate chromosomes during cell division When reproducing the centrioles are separated When growing the centrioles are together

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25 NUCLEUS Controls all cell activity Contains the DNA of eukaryotic cells Enclosed by a nuclear envelope that is porous When growing the DNA is in the form of chromatin DNA fibers and protein When reproducing the chromatin coils around the proteins to form chromosomes

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28 NUCLEOLUS Found within the nucleus Contains RNA which is used to make ribosomes / /animations/cell_structure/cell _structure.htm iz/target_practice_quiz_cells.htm

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30 PLANT CELLS 1. Cell Wall lies outside the cell membrane composed of cellulose & proteins primary cell wall forms outside the cell membrane during cell growth secondary cell wall forms between the primary cell wall & cell membrane when growth stops middle lamella glue like substance that binds layers together

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32 2. Vacuoles Fluid filled organelles that store enyzmes, water and waste Take up the most volume in the cell Displaces the nucleus Turgor pressure pressure created in vacuole as it fills with water

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34 3. Plastids A. Chloroplasts contain chlorophyll that absorbs sunlight needed for photosynthesis

35 B. Chromoplasts store other pigments C. Leucoplasts stores starch & fats