The Cell
I. Cell Theory
A. Three parts
1. All living things are made of cells
2. The cell is the basic unit of life
3. New cells are made by other living cells
II. Two kinds of cells
A. Prokaryotic
1. No membrane-bound organelles
2. Single-celled organisms
B. Eukaryotic
1. Membrane-bound organelles
2. Singled-celled and multi-cellular organisms
III. Eukaryotic Cell Structure
A.
Organelles
1.
“Small organs”, structures that perform vital functions for the cell
2.
Present in all eukaryotic cells
a. Cell Membrane*
i. Controls what goes in and out of the cell
ii. Phospholipid bilayer
b. Cytoplasm
i. Gel-like substance that fills the cell
ii. Holds many monomers for the cell to make polymers with
c. Cytoskeleton
i. Provides support
ii. Protein fibers that criss-cross the whole cell
d. Centrosome
i. Produces microtubules for various processes
- Microtubules are small protein fibers
- Can be used for structure or for cellular
division
e. Nucleus*
i. Stores the DNA of a cell
ii. It must protect the DNA, but also make the DNA available
for use
- Nuclear Membrane has pores that allow only
DNA and special proteins to pass through
- Nucleolus is a dense area of DNA that makes
ribosomes
f.
Smooth Endoplasmic Reticulum
i. Makes lipids
g. Rough Endoplasmic Reticulum
3.
4.
i. Is covered in ribosomes
ii. These make proteins that will go to the cell membrane, or
be secreted
h. Ribosome*
i. Tiny organelles that link amino acids together to make
proteins
ii. Some are suspended in the cytoplasm
- They make proteins that will be used for
chemical reactions
i. Golgi Apparatus
i. Puts the finishing touches on some proteins
ii. Packages them for delivery inside the cell and outside the
cell
j. Vesicle
i. Small membrane-bound sacs that safely transport materials
in the cell
k. Vacuole
i. A fluid-filled membrane-bound sac that stores materials
l. Mitochondrion*
i. Converts molecules from food (glucose) into usable energy
ii. Have their own DNA and ribosomes
Plant Cells
a. Central Vacuole
i. Huge fluid-filled membrane-bound sac that takes up most of
a plant cell
ii. Adds support and rigidity to the cell
b. Chloroplast*
i. Converts solar energy into chemical energy
c. Cell Wall
i. Gives the cell it’s structure and makes the cell more rigid
ii. In plant, algae, and bacteria cells
Animal Cells
a. Lysosome
i. Contains enzymes to break down invaders, or old cell parts
b. Centriole
i. Specially arranged microtubules made by the centrosome
ii. Help with cell division