Basic cell parts: cell membrane and cytoplasm

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Basic cell parts cell membrane and cytoplasm

• Cell membrane
• provides barrier between internal and
  external environment of cell
• is semi-permeable (some things can go in,
  some cannot some things can exit, some
  never can)
• made up of phospholipid bilayer with
  proteins embedded that allow for needed
  passage of large molecules

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• Major job of cell membrane is to maintain the
  cells environment establish homeostasis

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• Major job of cell membrane is to maintain the
  cells environment establish homeostasis

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Nucleus

• Largest organelle
• Enclosed by nuclear envelope or membrane, which
  is a double membrane each of which is a lipid
  bilayer!!!
• Nuclear membrane has pores in it
• Contains inactive DNA chromatin
• When gets ready to divide, chromatin condenses
  into chromosomes
• Directs protein synthesis by synthesizing mRNA
  and sending to ribosomes in the cytoplasm

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Figure 7.6 The plasma membrane
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Cytoplasm

• Entire region between the nucleus and the cell
  membrane
• The semifluid substance that fills this area is
  called CYTOSOL, and this is what the organelles
  are suspended in

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Cell Wall

• Found in plant cells (another barrier in ADDITION
  to the cell membrane)
• Protects the cell
• Gives support to cell
• Made of polysaccharide called cellulose
• Is very porous and allows molecules to pass
  through, but is NOT SELECTIVELY PERMEABLE

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Endoplasmic Reticulum highway system

• Internal transport system for the cell
• Fine network of tubes or canals located within
  the cytoplasm of a cell
• Job is to transport materials quickly from one
  place to another in cell

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Rough Endoplasmic Reticulum

• Has ribosomes on its surface
• Functions to manufacture proteins that are then
  transported inside the ER

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Smooth Endoplasmic Reticulum

• Does not have ribosomes on the surface
• Manufactures enzymes that can break down harmful
  substances

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Ribosomes

• Involved in making proteins
• Found floating freely in cytoplasm and attached
  to endoplasmic reticulum
• Cells with high rates of protein synthesis have
  MANY ribosomes (human pancreas cell has MILLIONS
  of ribosomes)
• Are free ribosomes in cytosol that make
  proteins for the cell that they are INSIDE of
• Ribosomes that are attached to endoplasmic
  reticulum (bound) are making proteins for
  packaging and export OUTSIDE OF CELL

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Golgi apparatusGift wrapper/UPS system

• Finishes, sorts, ships cell products
• Golgi will modify products as needed gives more
  variety by removing some monomers and
  substituting others

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VacuolesBank Vaults or trash cans

• Sites of storage in cells
• good things stored water, minerals,
• food etc.
• bad things stored broken down cell parts,
  waste

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Lysosome suicide bags

• Contain digestive enzymes often called the
  Digestive Bag of the Cell
• Different lysosomes break down each of the major
  classes of macromolecules proteins,
  polysaccharides, fats, nucleic acids
• Work best at pH of 5
• Located in the cytoplasm

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Mitochondria and Chloroplastspowerhouses

• Mitochondria carry on cellular respiration
  sites of energy production in cell (glucose
  broken down to produce ATP)
• Chloroplasts carry on photosynthesis
• sites where sunlight, CO2 and water are
  converted into glucose

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Mitochondria

• Power plant of the cell
• Site of cellular respiration
• Found in the cytoplasm
• More are in muscle cells than in skin cells

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Chloroplasts

• Site where photosynthesis occurs
• Found in the cytoplasm of plants and some other
  organisms
• Round, green structure that contains chlorophyll

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Centrioles

• Involved in cell division
• Found in the cytoplasm near the nucleus of animal
  cells

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