CELL ORGANELLES

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CELL ORGANELLES

• Biology

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Cell Organelle

• Organelles are membrane bound structures within
  eukaryotic cells that carry out cellular
  metabolism
• Note it is the enzymes contained inside the
  organelles that actually perform the functions.

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Cytoplasm

• The aqueous liquid inside a cell that all
  organelles float around in.

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The Nucleus

• The central command center in eukaryotic cells
  that contains DNA
• Also contains the nucleolus, which makes
  ribosomes.
• Enlosed by the nuclear envelope, which is a
  porous double membrane that controls what goes in
  and out.

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The Smooth Endoplasmic Reticulum (SER)

• Part of the endomembrane system (ES) that is
  connected to the nucleus.
• Called smooth because no ribosomes attached to
  it.
• The SER produces lipids, contain important
  enzymes in liver cells, and store calcium ions in
  muscle cells.

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Rough Endoplasmic Reticulum (RER)

• Part of the ES
• Called rough because it is dotted with
  ribosomes.
• RER makes more membrane
• RER modifies proteins made by ribosomes, such as
  secretory proteins, which are shipped out in
  transport vesicles.

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Golgi Apparatus

• Receives products from the ER
• Sorts and modifies proteins from ER, then ships
  them to the membrane or out of the cell via
  transport vesicles.

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Lysosomes (animal cells)

• Sacs filled with digestive (hydrolytic) enzymes
• Part of the ES
• Packed with enzymes and released from the Golgi
  Apparatus
• They fuse with food molecules or bacteria and
  digest (hydrolyze) them.

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Vacuoles

• Membranous sacs (part of ES) that store stuff.
• Central Vacuole (in plants) store pigments to
  attract insects or poisons for defense.
• Some vacuoles in protists collect excess water
  and expel it.

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Mitochondria (singular Mitochondrion)

• CELL RESPIRATION OCCURS HERE!!!
• Cell respiration is the conversion of sugar
  molecules into energy usable by cells (ATP!!!)

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Chloroplasts (in plants)

• PHOTOSYNTESIS OCCURS HERE!!!
• Photosynthesis is the conversion of sunlight
  energy into sugar molecules.

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Cytoskeleton

• A network of protein fibers that provide
  structural support for cells.
• Microfilaments solid rods made of actin
  protein, just inside the membrane to support cell
  shape
• Intermediate Filaments rope like proteins that
  anchor organelles in place.
• Microtubules composed of tubulin protein,
  movable structures that can act as cellular
  railroad tracks and support beams.

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Cilia and Flagella

• Cilia short, numerous membrane projections on
  some cells that move particles along a tissue
• Flagella long, less numerous membrane
  projections on some cells that wiggle to move
  the cell along (like in sperm cells).

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Cells with specific functions may have more of
certain organelles.

• Muscle cells have many mitochondria to produce
  lots of ATP (energy)
• Ovarian and Testicular cells contain lots of SER
  to produce lipid based sex hormones.

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Extracellular Matrix

• The collection of sticky glycoproteins secreted
  by animal cells that form junctions and hold
  tissues together.
• Tight Junctions bind cells together, forming a
  leak-proof sheet (in digestive tract)
• Anchoring Junctions form strong sheets to resist
  stress (in skin and heart tissue)
• Gap Junctions have small spaces in them to allow
  molecules to pass through tissue (in heart muscle
  and embryonic tissue).

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ALL DONE!