1. The Diversity of Cells Ch. 3-1 How were they discovered?
~ Robert Hooke looked at a slice of cork
- saw "little boxes" and called them "cells"
~ Anton von Leeuwenhoek first to observe pond water under a microscope
Over next 150 years, people like Schleiden, Schwann, and Virchow researched cells
This led to…
Cell Theory - 3 parts
1.) All living things are composed of 1 or more cells
2.) In organisms, cells are basic units of structure and function
3.) Cells are produced only from existing cells

2. Cells must be small!
~ must be able to exchange materials
in and out of the cell
~ move materials within the cell
~ efficiency depends on ratio of surface area to volume
*small cells are more efficient
~ Cell shape can affect how it works too...
ex: skin cells are flat and thin, nerve cells
are long and skinny - these shapes help it to work better!

3. Characteristics of all cells:
1.) Cell membrane - (plasma membrane)
* separates the cell's insides from the material outside the cell
* regulates what moves in and out of the cell
*necessary for life
2.) Cytoplasm - everything inside the cell except the cell's genetic make-up (DNA)
* cytosol - fluid portion!
3.) Ribosomes - structures on which proteins are made
* found in cytosol

4. Extremophiles! 2 Types of cells:
1.) Prokaryotes - single-celled organisms
~ NO NUCLEUS!!
* 3.5 by old - very small
* cannot do many specialized functions
* some have flagella or cilia to help move around
a.) Eubacteria - these are common bacteria!
* ARE EVERYWHERE!!
* can be very helpful - in your gut
* can also be harmful - cause disease
b.) Archaebacteria - similar to bacteria but have different ribosomes, different type of cell wall, and live in harsh environments
~ 3 types:
*heat-loving - live in hot springs or by thermal vents
*salt-loving - live in very salty water
*methane-making - live near volcanic vents and in swamps
Extremophiles!

5. 2.) Eukaryotes
* have a true nucleus
* eu: true karyote: kernel
* have organelles that carry out specific functions
Can be unicellular or multicellular!

6. Eukaryotic Cells Ch. 3 - 2 is selectively permeable!!
Each cell has many compartments-
* divided by membranes that make little areas for specific structures
Cell membrane - made of phospholipids
hydrophilic heads
hydrophobic tails
sticks to water
repels water
~ framework called a cytoskeleton
~ made of microfilaments, microtubules, and intermediate
fibers
~ all work to give the cell support, shape, help it move, and stay organized
is selectively permeable!!

7. Nucleus:
~ has nuclear envelope with pores
(holes)
~ contains DNA
~ has nucleolus that makes
ribosome parts
*these parts are put together outside the nucleus

8. Ribosomes:
~ make proteins to be used in or
outside the cell
a put these in a package called a vesicle
The organelles that do this packaging? ER and Golgi apparatus!
Endoplasmic Reticulum (ER):
~ moves proteins through the cell
2 kinds:
* Rough ER - has ribosomes on it!
~ looks rough!
~ makes and packages proteins to go to the GA
*Smooth ER - no ribosomes
~ makes lipids and breaks down toxic substances

9. Golgi Apparatus! Golgi Apparatus (GA):
~ modifies, sorts, and packages cell products
~ when finished, the package leaves the GA and often leaves the cell
Golgi Apparatus!

10. Storage and Maintenance:
Lysosomes:
~ vesicle that has enzymes to break down large molecules
~ also recycles old, damaged, or unused organelles
Vacuoles:
~ large spaces for storage
~ plants have large central vacuoles for water storage
Chloroplasts:
~ PLANTS ONLY!!
~ uses light energy to make sugar

11. mitochondrion Mitochondria: ~ Powerhouse of the cell - like a battery!
~ makes ATP - energy currency, remember?
mitochondrion

12. Organization of Living Things
3-3
We can order cells into different levels of organization:
1.) Tissues - group of cells with
similar structures
and functions
Ex: muscle tissue

13. 2.) Organs - dif. tissues come together to make an organ that has a specialized
structure and function
Ex: heart - made of muscle, nerve and
other tissues

14. 3.) Organ systems - organs working together with major body functions
Ex: circulatory system - made of heart, blood vessels, and blood
4.) Organism - anything that can perform life processes by itself
*unicellular - made of just one cell
~no specialization
Only eukaryotes have true multicellularity (more than one cell)
~ they come from one cell that divides and then those cells differentiate, or become specialized