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LOOKING INSIDE CELLS
CHAPTER 2 SECTION 4
INTRODUCTION
• Organelles
• Tiny structures that carry out specific
functions within the cell
• Compare to organs in your body…
CELL WALL
• Rigid layer of nonliving material that
surrounds the cells of PLANTS
• Function: helps to protect and support the cell
• Made of cellulose
• Animal cells DO NOT have cell walls
CELL MEMBRANE
• In cells with cell walls, the cell membrane is
located just inside the cell wall
• In other cells, the cell membrane forms an
outside boundary
• Function: controls what substances come into
and out of a cell
PARTS OF THE NUCLEUS
• Nucleus
• Acts as the “brain” of the cell
• The cell’s control center, directs cell’s activities
• Nuclear envelope
• Nucleus is surrounded by this membrane
• Materials pass in and out of the nucleus through pores in this
structure
• Chromatin
• Contains instructions that direct the functions of a cell
• Thin strands, contain genetic material
• Nucleolus
• Where ribosomes are made
THE NUCLEUS
ORGANELLES IN THE CYTOPLASM
• Cytoplasm
• The region between the cell membrane and
the nucleus
• Clear, thick, gel-like fluid
• Many organelles are found in the cytoplasm
MITOCHONDRIA
• Convert energy in food molecules to energy the
cell can use to carry out its functions
• “powerhouse”
ENDOPLASMIC RETICULUM
• Passageways carry proteins and other
materials from one part of the cell to another
• Mail truck
RIBOSOMES
• Function as factories to produce proteins
• Sometimes attached to the endoplasmic
reticulum or float in cytoplasm
GOLGI BODIES
• Receive proteins and other newly formed
materials from the endoplasmic reticulum,
package them, and distribute them to other
parts of the cell
• Mail room
CHLOROPLASTS
• Capture energy from sunlight and use it to
produce food for the cell
• Only in plant cells
VACUOLES
• Storage area of cells (food and other materials)
• Plants cells have ONE large vacuole
• Animal cells have many small vacuoles, or none
at all
LYSOSOMES
• Small, round structures containing chemicals
that break down certain materials in the cell
• “garbage truck”
SPECIALIZED CELLS
• In many-celled organisms, the cell are often
quite DIFFERENT from each other
• Cells are specialized to perform specific
functions
• Cells ---- Tissues ---- Organs ---- Organ Systems