1. CELL SPECIALIZATION
Sections 2.3/2.4

2. SPECIALIZED CELLS
Cells are specialized to carry out specific functions
Cells are generally more efficient when they work together to perform a specific function

3. SPECIALIZED ANIMAL CELLS
nerve cells: conduct electrical signals, long and thin
respiratory cells: thin to allow gases to exchange between air and blood; coated in mucus and/or cilia to help remove harmful particles
red blood cells: carry oxygen in hemoglobin (a protein)
white blood cells: engulf invaders and digest them or kill them with antibodies
stomach cells: have many Golgi apparatuses; produce and store proteins that break down food; protected from stomach acid by mucus
fat cells: store extra body nutrients in vacuoles by converting them to fat
small intestine cells: absorb essential nutrients from food by means of villi (finger-like projections that increase the surface area of the cell)

4. red and white blood cells
SMALLER VERSUS LARGER
The bigger the cell is, the longer messages take to reach the nucleus and the slower the cell will react
Larger the ratio of cell membrane area to cell volume, the more efficient it can be in absorbing nutrients and eliminating wastes
i.e. many small cells are more efficient at getting nutrients in and wastes out than one large cell

5. What is larger, muscle cell or fat cell?
Muscle cells are more active cell, thus the need for more nutrients and produces more waste
The more active the cell, usually the smaller it is.

6. SPECIAIZED CELLS (SKIN CELLS AND SUNLIGHT)
Skin cells must be small so that the chemical message triggered by sunlight can reach the nucleus quickly.
This message tells ribosomes to make melanin, which protects the skin cells by blocking sunlight and also causes the skin to darken.

7. SPECIALIZED PLANT CELLS
Different types of cells are designed to carry out special functions
thin-walled plant cells: found in flexible tissue or leaves, flowers, roots
thick-walled plant cells: specialized for support; are stretchable and flexible
very thick-walled plant cells: provide rigid support
Cell walls can get so thick that nutrients will eventually have trouble entering the cell  usually die leaving empty chambers surrounded by hardened thick cell walls
Example: tree trunks