CELL STRUCTURE AND FUNCTION


I. The cell theory
All living things are composed of cells
Cells are the basic unit of structure and function of all living things
All cells come from the division of preexisting cells
II. Cell structure
A. Cell membrane
Aids in the protection and support of the cell
Cell membrane is composed of a bilayer of lipids, protein channel, protein molecule, and carbohydrate
chains
B. Nucleus
Not all cells have nuclei
Give instructions
Contain DNA
1. Eukaryotic
Contained in animals and plants
Nucleus surrounded by 2 membranes called nuclear envelope
2. Prokaryotic
No nucleus
Contained by bacteria
3. Nucleolus
Made up of RNA and proteins
Structure in which ribosomes are made
4. Chromosomes
Contain DNA
C. Cytoplasm
Area between nucleus and cell membrane
III. Cytoplasmic Organelles
A. Mitochondria
Turns chemical energy into compounds easily used by cells
Cellular respiration occurs within
B. Chloroplasts (plants)
Trap energy of sunlight and convert it into chemical energy for the cell
C. ER (endoplasmic reticulum)
Smooth- stores enzymes and other chemicals
Rough- Has ribosomes
D. Cytoskeleton
Microtubules- Provide support for shape, help move organelles, and play a roll in cell division
Microfilaments- function in movement and support of the cell
IV. Movement of materials through cell membrane
A. Diffusion
The process by which molecules of a substance move from areas of higher concentrations of that
substance to areas of lower concentrations
B. Osmosis
Movement of water across the membrane by diffusion
C. Transport
1. Active
Process that requires energy
Enables material to move across a cell membrane
2. Passive
Process that doesn't require energy
Osmosis and diffusion are forms passive transport
V. Levels of organization
A. Cells
1. Prokaryotic
2. Eukaryotic
B. Tissues
1. Muscles
2. Nerves
C. Organs
1. Hearts
2. Lungs, etc.
D. Organ systems
1. Digestive
2. Circulatory, etc.