Organelles

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Organelles

• Control
• Nucleus (plant and animal)
• Assembly, Transport, and Storage
• Nucleolus (plant and animal)
• Endoplasmic reticulum (plant and animal)
• Ribosomes (plant and animal)
• Golgi apparatus (plant and animal)
• Vacuoles (plant and animal)
• -one BIG one in plants multiple small ones in
  animals
• Lysosomes (plant and animal)
• Energy transformations
• Chloroplasts (plant only)
• mitochondria (plant and animal)

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Nucleus

• Contains most of eukaryotic cells genetic
  library (mitochondria and chloroplasts contain
  their own DNA)
• Largest organelle
• Enclosed by nuclear envelope or membrane, which
  is a double membrane each of which is a lipid
  bilayer!!!
• Nuclear envelope has pores in it
• Contains inactive DNA chromatin

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Nucleolus

• Prominent structure in non-dividing nucleus
• Ribosomal RNA and ribosomal subunits are made here

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Figure 7.9 The nucleus and its envelope 
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Endoplasmic reticulum highway system

• EXTENSIVE accounts for more than half the total
  membrane system in eukaryotic cells
• Name means little net within the cytoplasm
• Smooth and rough e.r. are actually connected, not
  distinct, separate sections
• Job is to transport materials quickly from one
  place to another in cell

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Figure 7.11 Endoplasmic reticulum (ER)
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Smooth e.r.

• Functions in synthesis of lipids, metabolism of
  carbs, detoxification of drugs and poisons
• Lipids oils, phospholipids, steroids
• (sex hormones and adrenal hormones)
• Liver cells glycogen gets converted to
  glucose phosphate which cannot leave cell,
  so e.r. makes enzyme that converts this to
  glucose
• Detox liver adds hydroxyl groups to drugs,
  makes them soluble and able to be flushed
  out of body

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Rough e.r.

• Makes secretory proteins
• (ex. Insulin made by pancreatic cells)
• Most are glycoproteins (proteins covalently bound
  to carbs)
• Rough e.r. is also a membrane factory grows by
  adding proteins and phospholipids parts can be
  taken from here and added to other membrane
  systems using the vesicles for transport

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Ribosomesprotein factories

• Sites of protein synthesis
• Are made of rRNA and protein
• 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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Figure 7.10 Ribosomes
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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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Figure 7.12 The Golgi apparatus
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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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Lysosomessuicide bags

• Membrane-bounded sac of hydrolytic enzymes
• Different lysosomes break down each of the major
  classes of macromolecules proteins,
  polysaccharides, fats, nucleic acids
• Work best at pH of 5
• Used in autophagy recycle the cells own
  organic material for use

15
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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Figure 7.17 The mitochondrion, site of cellular
respiration
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Figure 7.18 The chloroplast, site of
photosynthesis
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Other structural components of cell

• Cytoskeleton
• Cilia and flagella

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Cytoskeletonhay in mud makes bricks

• Network of fibers extending into cytoplasm of
  cell
• Provides structural support, and aids in cell
  motility and cell regulation
• Made up of microtubules (thickest), microtubules
  (thinnest), and intermediate filaments

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Cilia and Flagellahairs and tails

• Cilia are short projections from cell body
  hair-like
• flagella are much longer whip-like
• Movement may not be for entire organism may be
  part of a larger unit ex. Cilia lining windpipe
  propel foreign substances out

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Organelles do not work alone

• Cell is a dynamic interaction of ALL of its parts
  literally, the basic unit of life.