Chapter 7: Cell Structure &
Function
7.1 & 7.2
Discovering the Cell
For a long time, we didn’t know cells
existed.
They were too small to see with the naked
eye!
What invention changed this?
Discovering the Cell
The invention of the microscope
changed how we look at living things
We use a compound light
microscope.
Can see the Cell Membrane & Nucleus
Can not study internal structures of organelles
Electron Microscope
Discovery of the Cell
Robert Hooke: saw a honeycomb
structure when examining cork under
the microscope
Named these structures cells, meaning
“storage rooms”
Discovery of the cell
Van Leeuwenhoek
Observed microorganisms in pond
water, tooth scrapings, and saliva
Cell Theory
Three parts
Cells are the smallest/basic units of life
All living things are made up of cells
All cells come from preexisting cells
http://ed.ted.com/lessons/the-wackyhistory-of-cell-theory
Levels
smallest
Macromolecules (last unit)
Organelle (cell parts such as the
nucleus or mitochondria)
Cell
Tissue
Organ
Systems
biggest
Organism
Different cell categories
Prokaryote: cell
without a nucleus
or most organelles
Ex. bacteria
Eukaryote: cell with
a nucleus and
organelles
Ex. animal cell
2 types of Eukaryotic Cells
Animal
Plant
Cell Membrane
• Controls what enters and exits the cell
• Made of phospholipids  bilayer
Nucleus
• Only in a eukaryotic cell
• “Boss”  controls the cell
• Stores & Protects the DNA
Cytoplasm
• “Jelly” that holds cell structures in place
Mitochondria
• “Power House”
• Make ATP  energy source
• CELL RESPIRATION
Cell Respiration
Converts chemical energy in food
to usable energy in the form of
ATP
Ribosome
• Make Proteins
• Found Free or Attached
to the ER (Endoplasmic
Reticulum)
Endoplasmic Reticulum (ER)
• Manufactures (aka makes) important substances for
the cell.
• Helps the Ribosome!
• Rough ER 
Ribosomes
attached to it
• Smooth ER
• Found outside
of the nucleus
Golgi Apparatus
• Packages & Ships substances produced by the cell
Lysosome
• Digests/Breaks
down waste, old
parts, foreign
substances &
recycles them.
• Rarely found in
plants cells.
Centrioles
Important for cell
division!
Help to organize &
move
chromosomes
during mitosis.
Mainly found in
animal cells
Cilia and Flagella
• Cilia
– Look like hair
• Flagella
– A tail
Plants Cell
• Plant cells have a few differences!
– Cell Wall
– Large Vacuoles
– Chloroplasts
Cell Wall
• Rigid  Helps support, shape & protect the cell
• Made of Cellulose
Vacuole
• Fluid filled sac
• Stores enzymes,
waste, & water
• Also found in
animal cells but
they are much
smaller
Chloroplast
• Stores pigments
that convert
sunlight to cell
energy 
photosynthesis!