2-Cells-pro vs euk

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Transcript 2-Cells-pro vs euk

The Building Blocks of Life
Cells are Us
A person contains about 100 trillion
cells. That’s 100,000,000,000,000 or
1 x 1014 cells.
There are about 200 different cell
types in mammals (one of us).
Cells are teeny, tiny, measuring on
average about 0.002 cm (20 um)
across. That’s about 1250 cells,
“shoulder-to-shoulder” per inch.
nerve cell
Why Study Cell
The key to every
biological problem
must finally be sought
in the cell, for every
living organism is, or
at some time has
been, a cell. E.B.
Wilson, 1925
The Cell Theory (review)
The Cell Theory (proposed independently in 1838 and
1839) is a cornerstone of biology.
 Cells are the basic unit of life
 All Cells arise from previously existing cells
Cell Structure and Function
• What are the common features of all
• What is the difference between
prokaryotic and eukaryotic cells?
Two Types of Cells
Two Fundamentally Different Cell Architectures:
1) A prokaryotic cell
2) A eukaryotic cell
Prokaryotic cells
• have no nucleus or organelles
enclosed within membranes.
• All species in the domains Archaea and
Eubacteria have prokaryotic cells.
Eukaryotic cells
• have a nucleus and organelles that are
surrounded by membranes.
• Each organelle does a specific cell function.
• All species in the Eukaryota domain (protists,
fungi, plants, and animals) have eukaryotic cells.
Individual protists have only one cell, while plants
and animals can have trillions of cells.
Prokaryotes vs. Eukaryotes
Size comparison??
• 1. A few types of cells
are large enough to be
seen by the unaided
• 2. Most cells are
visible only with a
•The Female Egg is the largest cell in the body, and can be seen
without the aid of a microscope.
Similarities: Common Features
The common features of prokaryotic
and eukaryotic cells are:
• 1. DNA
2. Plasma membrane (a.k.a. “cell membrane”)
• 3. Cytoplasm
• 4. Ribosomes
An idealized animal cell.
A rat liver cell (with color enhancement to show
What Do Those Parts