Chapter 7 Cells
Section 7-1
Cells: the basic unit of life
Cell Theory
1. All living things are made of cells.
2. Cells are the basic units of structure and function in living
things.
3. New cells can only come from other living cells.
Leeuwenhoek: developed the microscope and saw living
microorganisms in pond water
Hooke: looked at plant cells and cork with a microscope.
Called it a “CELL”
Basic Cell Structures
Cell Membrane: thin membrane that surrounds the cell
Cell Wall: strong layer around the membrane
 Protects the cell
 NOT in Animal cells
Nucleus: genetic material; control center of the cell
Cytoplasm: jelly-like substance that contains other organelles.
http://cellsalive.com/cells/cell_model.htm
Cheek Cell- Animal
Onion Cell-Plant
Cell Wall
Cytoplasm
Cell
Membrane
Nucleus
Prokaryotes: Simple cell
 No Nucleus
 Example: bacteria
Eukaryotes: Complex Cell
 Has a nucleus
 Example: Human Cell
Section 7-2
Cell Structures
1. Cell Wall: Found in PLANTS, ALGAE, FUNGI, and
PROKARYOTES (No Nucleus)
 NOT in animal cells
 Made from protein and carbohydrates
 protects and supports the cell
2. Nucleus: Controls the cell and contains hereditary
information (DNA)
 Only in Eukaryotic cells
a. Chromosomes: Made of chromatin and contains
genetic information
b. Nucleolus: Assembly of ribosomes
3. Nuclear Envelope: Surrounds the nucleus
4. Cytoskeleton: supports the cell, helps it to keep its shape,
involved in cell movement
 microtubules: Hollow tubes of protein
 Microfilaments: long thin fibers that aid in cellular
movement
5. Ribosomes: one of the most important jobs in the cell is to
make protein
 Proteins are assembled here
6. Endoplasmic Reticulum: makes part of the cell membrane
and some proteins (“ER”)
 Rough Endoplasmic Reticulum: Has Ribosomes on it
 Smooth Endoplasmic Reticulum: No Ribosomes on it
Rough Endoplasmic
ReticulumRibosomes
Smooth Endoplasmic
Reticulum- NO
Ribosomes
7. Golgi Apparatus: Contains Enzymes that attach
carbohydrates and lipids to proteins
8. Lysosomes: small organelles filled with digestive enzymes
 breaks down carbs, lipids, proteins so it can be used by
the rest of the cell
 removes and breaks down old, worn out organelles
9. Vacuole: stores water, salt, protein and carbs
10. Chloroplast: Contains Chlorophyll
 Green pigment in plants
 ONLY in Plant cells
11. Mitochondria: uses energy from food to make energy
compounds
 Powerhouse of the cell
 found in ALL Eukaryotic cells
 Contains DNA from MOM.
Section 7-3
 regulates what enters and leaves
 protects and supports
 Lipid Bilayer: double layered sheet that helps to create a
strong, flexible structure
 Protein Channel: helps to move material across the cell
membrane
 Carbohydrate Chains: act as ID cards
Diffusion
Causes materials to move across the cell membrane from
HIGH concentration to LOW concentration (“Passive
Transport)
NO ENERGY NEEDED
Stops when equilibrium is reached.
Low Concentration
High
Concentration
Cell Membrane
Osmosis: Diffusion of water
Facilitated Diffusion: molecules (Glucose) that cannot pass
through the lipid bilayer pass through protein channels
NO ENERGY REQUIRED
Active Transport: Low concentration to High Concentration
ENERGY REQUIRED
High
Concentration
Low
Concentration
Exocytosis: removal of material
Phagocytosis: Taking in material
Chapter 7-4
Unicellular organism: A single celled organism
 They grow, respond to their environment and reproduce
 Can be either Prokaryotic (No Nucleus) or Eukaryotic (has
a nucleus)
 Colonial Organism: live in groups (“Colony”)
o Example: bacteria
Multicellular organisms: Organisms with more than 1 cell
 Example: Humans
 Specialized cells: Perform particular functions within the
organism
o Example: red blood cells, nerve cells, skin cells, etc.
Levels of organization
Individual cells
Tissue
Organ
Organ
System