Download CP-Chapter7-Discovery of cells

Study the image…
DO NOW:
• 1. Do you think the structure of the onion cells
determines the overall size and shape of the
plant? Explain your answer.
• 2. If one cell of the onion were changed or
damaged, how might it affect the overall
structure or function of the plant?
• 3. If one cell is not important to the survival of
the plant, why is it still worthwhile to study
plants at the cellular level?
The Discovery of Cells
• Cell
– smallest unit
that can
perform all
life
processes
The Cell Theory
• 1. all living things are composed of one
or more cells (Hooke)
• 2. cells are the basic units of structure
and function in an organism (Schleiden
& Schwann)
• 3. cells come only from the reproduction
of existing cells (Virchow)
Hooke (1665)
• Used early light microscope
• Observed cork cells from a dead oak tree
• Called the cells “little boxes”
Leeuwenhoek (1678)
• First person to observe living cells
• Saw bacteria
• Saw protists in pond water
– Spirogyra
Schleiden (1839)
• Viewed plant cells
• Organisms composed of cells, the basic
units of life
Schwann (1839)
• Viewed animal cells
• Organisms composed of cells, the basic
units of life
Virchow (1855)
• “every cell originates from a pre-existing
cell”
Do Now:
1. Study the cell at your lab table.
1. When you are finished, switch with the lab
table next to you.
1. Write down the FOUR things you think ALL
CELLS HAVE!
Cell Shape
& Size
• Diversity in
shape reflects
function
• Shape can be
simple or
complex
Four (4) Things all cells have
•
•
•
•
1. Plasma (cell) membrane
2. Cytoplasm
3. Hereditary material
4. Ribosomes
Basic Parts of a Cell
• 1. Plasma (cell) membrane
– Selectively permeable
– Covers surface
– Acts as barrier
Basic Parts of a Cell
• 2. Cytoplasm
– Fluid between membrane & nucleus/nucleoid
– Contains cytoskeleton & organelles
Basic Parts of a Cell
• 3. Hereditary Material
– Nucleus (eukaryotic)
• Contains DNA
– Nucleoid (prokaryotic)
• Contains hereditary info (DNA/RNA)
Basic Parts of a cell
• 4. Ribosomes
– In cytoplasm
– Where protein synthesis (making proteins)
occurs
Types of Cells
• Prokaryotic Cells
• Eukaryotic Cells