Section 3: Cell Organelles

1
Section 3 Cell Organelles

• The Nucleus
• Eukaryotic cells (plant and animal cells) have a
  nucleus
• It is surrounded by a double membrane called the
  nuclear envelope
• Holes in the nucleus called nuclear pores allow
  ribosomes to pass through and get out to the
  cell.
• DNA is contained in the nucleus which contain
  hereditary information

2
Ribosomes and the Endoplasmic Reticulum (ER)

• Proteins are made on ribosomes that are on the
  rough endoplasmic reticulum.
• There are two types of endoplasmic reticulum
  smooth and rough, smooth do not have ribosomes,
  rough do
• Smooth endoplasmic reticulum have various
  functions such as making lipids and breaking down
  toxic substances

3
Packaging and distribution of proteins

• The golgi apparatus is a set of flattened,
  membrane bound sacs that serve as the packaging
  and distribution center of the cell
• Proteins received from the ER travel to the golgi
  apparatus where they are modified by enzymes,
  then packaged and exported from the cell in
  vescicles
• Production, packaging, and distribution of
  proteins is starts in the rough ER , goes through
  the golgi apparatus, to the outside of the cell
  with the assistance of vesicles and lysosomes

4
mitochondria

• An organelle that harvests energy from organic
  compounds, such as carbohydrates, to make ATP
  which can be used by the cell to make energy.
• See p. 65
• The mitochondria has two membranes, inner and
  outer, the inner membrane is intricately folded
• Cells with a high energy requirement, such as
  muscle cells, may contain thousands of
  mitochondria
• Mitochondria have their own DNA and can make
  their own proteins which lends evidence that the
  first life on Earth were related to mitochondria

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Plant cells

• In addition to the organelles previously
  discussed, plant cells have
• A cell wall, composed of proteins and
  carbohydrates such as cellulose, it helps
  maintain and protect the cell
• Chloroplasts, which use light energy to make
  carbohydrates during photosynthesis
• Central vacuole, which is a large membrane-bound
  space which holds water and nutrients as well as
  wastes. When full it makes the cell rigid