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Cells. The Building Blocks of Life. nerve cell. Cells are Us. A person contains about 100 trillion cells. That’s 100,000,000,000,000 or 1 x 10 14 cells. There are about 200 different cell types in mammals (one of us). - PowerPoint PPT Presentation
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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
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
Why Study Cell Biology?
The Cell Theory (review)
Cells are the basic unit of life
All Cells arise from previously existing cells
The Cell Theory (proposed independently in 1838 and 1839) is a cornerstone of biology.
TODAY:
Cell Structure and Function • What are the common features of
all cells?
• What is the difference between prokaryotic and eukaryotic cells?
Two Types of Cells
1) A prokaryotic cell
2) A eukaryotic cell
Two Fundamentally Different Cell Architectures:
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.
Size comparison??
• 1. A few types of cells are large enough to be seen by the unaided eye.
• 2. Most cells are visible only with a microscope.
•The Female Egg is the largest cell in the body, and can be seen without the aid of a microscope.
PROKARYOTES vs. EUKARYOTES: Differences
(Location)
Similarities: Common Features of ALL CELLS!
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 organelles).
What Do Those Parts Do?
