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Chapter # 2
Cells
Sec. 2-1 Cell Structure
Cell – The smallest unit that is capable of performing life functions.
Common Cell traits:
1. Cell Membrane – The outer covering of the cell.
2. Cytoplasm – a gel-like material inside the cell membrane that contains the cell organelles,
hereditary material, and is the location of most of the cell’s life processes.
Two groups of Cells:
1. Prokaryotic Cells – Cells without membrane-bound structures (bacteria).
2. Eukaryotic Cells – Cells with membrane-bound structures (Plants, Protists, Fungi, and
Animals are made of Eukaryotic cells.
Cell Organization:
Cell Wall – Tough, rigid outer covering that protects the cell and gives it shape. Cell walls are
found in plants, algae, fungi and most bacteria. The cell wall is made of a carbohydrate called
cellulose.
Cell Membrane – Protective layer around all cells that allows certain things such as water and food
in and out of the cell (selectively permeable).
Cytoplasm – a gelatin like substance that constantly flows inside the cell membrane; it holds the
organelles of the cell.
Organelles – Structures in the cytoplasm of eukaryotic cells that can act as a storage site, process
energy, move materials, or manufacture substances.
Nucleus – The control center of the cell. It is an organelle that controls all the activities of a cell and
contains hereditary material made of proteins and DNA. Usually the largest organelle.
Figure 6:
Plant and Animal Cells have a few differences- plant cells have all the structures found in animal
cells plus1. Cell Wall
2. Large Vacuoles
3. Chloroplasts
Chloroplasts – an organelle found in plant and algae cells where photosynthesis occurs.
Chloroplasts contain a green pigment called chlorophyll which gives leaves and stems their green
color. Chlorophyll captures light energy and uses it to make sugar called glucose.
Mitochondria – The powerhouse of the cell. A cell organelle surrounded by two membranes that
break down food molecules to make ATP (energy molecule).
Ribosome’s – Small organelles in the cell where proteins are made from amino acids. The most
numerous organelle.
Endoplasmic Reticulum – (ER) A membrane covered organelle that produces lipids, breaks down
drugs, and packages proteins for delivery out of the cell. An internal transportation system.
Golgi Bodies – The cell organelle that modifies, packages, and transports material out of the cell.
Lysosomes – contains chemicals that help break down food molecules, cell wastes, foreign invaders,
and worn out cell parts.
From Cell to Organism:
Cell – The smallest unit that is capable of performing life functions.
Tissue – a group of similar cells that work together to do one job
Organ – a structure made up of two or more types of tissue that work together
Organ System – a group of organs working together
Sec. 2-2 Viewing Cells
Magnifying Cells:
Magnify – to increase the size of something.
 the first microscope was made by a Dutch maker of reading glasses in the late 1500’s
but in the 1600’s another microscope was made by a man named Antoine van
Leeuwenhoek.
There are many types of microscopes:
1. Compound Light Microscope
2. Transmission Electron Microscope (TEM) 2D details of cell parts
3. Scanning Electron Microscope (SEM) 3D only surface features
Cell Theory:
1. All organisms are made up of one or more cells
2. The cell is the basic unit of life
3. All cells come from other cells
Sec. 2-3 Viruses
Cold sores, measles, chicken pox, colds, flu, AIDS, etc.
What are Viruses?
Virus – strand of hereditary material surrounded by a protein coating. Viruses do not have a nucleus
or other organelles and are not considered to be alive. They lack a cell membrane and can not
reproduce on their own.
* Viruses come in many shapes and sizes. They were discovered only days after the electron
microscopes were invented because they are too small to be seen with a compound light microscope.
Before the electron microscope it was hypothesized by scientists.
How do Viruses Multiply?
 all viruses can do is make copies of themselves, but they can not do it without the
help of a host cell.
Host Cell – a living cell in which a virus can actively multiply or in which a virus can hide until
activated by environmental stimuli.

The two ways that a virus can act inside a host cell are 1) it can become active, 2) it
can become latent

Viruses can sometimes affect a broad range of hosts
Fighting Viruses:
Vaccines – preparation made from killed bacteria or damaged particles from bacterial cell walls or
viruses that can prevent some bacterial and viral diseases.
Diseases that can be treated by vaccines include:
1. Measles
2. Mumps
3. Small pox
4. Chicken pox
5. Polio
6. Rabies
* The first vaccine was developed by Edward Jenner in 1796. He first developed it for small pox.
Chapter # 2 Vocabulary
Sec. # 1
1. Cell – The smallest unit that is capable of performing life functions.
2. Cell Membrane – The outer covering of the cell.
3.
Cytoplasm – a gel-like material inside the cell membrane that contains the cell organelles, hereditary material, and is the
location of most of the cell’s life processes.
4.
Prokaryotic Cells – Cells without membrane-bound structures (bacteria).
5.
Eukaryotic Cells – Cells with membrane-bound structures (Plants, Protists, Fungi, and Animals are made of Eukaryotic
cells.
6. Cell Wall – Tough, rigid outer covering that protects the cell and gives it shape. Cell walls
fungi and most bacteria. The cell wall is made of a carbohydrate called cellulose.
are found in plants, algae,
7. Cell Membrane – Protective layer around all cells that allows certain things such as water and food in and out of the cell
(selectively permeable).
8. Cytoplasm – a gelatin like substance that constantly flows inside the cell membrane; it holds the organelles of the cell.
9. Organelles – Structures in the cytoplasm of eukaryotic cells that can act as a storage site, process energy, move materials, or
manufacture substances.
10. Nucleus – The control center of the cell. It is an organelle that controls all the activities of a cell and contains hereditary material
made of proteins and DNA. Usually the largest organelle
11. Chloroplasts – an organelle found in plant and algae cells where photosynthesis occurs. Chloroplasts contain a green pigment
called chlorophyll which gives leaves and stems their green color. Chlorophyll captures light energy and uses it to make sugar called
glucose.
12. Mitochondria – The powerhouse of the cell. A cell organelle surrounded by two membranes that break down food molecules to
make ATP (energy molecule).
13. Ribosome’s – Small organelles in the cell where proteins are made from amino acids. The most numerous organelle.
14. Endoplasmic Reticulum – (ER) A membrane covered organelle that produces lipids, breaks down drugs, and packages proteins
for delivery out of the cell. An internal transportation system.
15. Golgi Bodies – The cell organelle that modifies, packages, and transports material out of the cell.
16. Lysosomes – contains chemicals that help break down food molecules, cell wastes, foreign invaders, and worn out cell parts.
17. Tissue – a group of similar cells that work together to do one job
18.
Organ – a structure made up of two or more types of tissue that work together
Sec. # 2
1. Magnify – to increase the size of something.
2. Cell Theory:
A.
B.
C.
All organisms are made up of one or more cells
The cell is the basic unit of life
All cells come from other cells
Sec. # 3
1. Host Cell – a living cell in which a virus can actively multiply or in which a virus can hide until activated by environmental
stimuli.
2. Vaccines – preparation made from killed bacteria or damaged particles from bacterial cell walls or viruses that can prevent some
bacterial and viral diseases.