Cells
All living things are made of
cells.
Overview
 Cells
are the basic units of structure
and function in living things.
 What does cell structure mean?

What it is made of and how its parts are
put together.
 What

does cell function mean?
the processes that enable it to stay alive
and reproduce.
 What
are some examples of cell
function?

Obtaining oxygen, getting rid of waste,
obtaining food, and growing
The First Observation of Cells
A
microscope is an invention that
makes smaller objects look larger.
 Robert Hooke was an English
scientist and inventor and the first
person to observe a cell.
 What did Hooke observe? Cork
 Who is Anton van Leeuwenhoek
and what did he view in a
microscope? A Dutch businessman
and he observed lake water,
scrapings from teeth and gums, and
water from rain gutters. He was also
the first to view single celled
organisms.
Cell Theory
 Who
are the three German Scientists who
developed Cell Theory?
Schleiden, Schwann, and Virchow.
 Cell Theory states:
1. All living things are composed of cells.
2. Cells are the basic unit of structure and function
in living things.
3. All cells are produced from other cells.
Microscopes


Light microscopes and electron microscopes
are two kinds of microscope scientists use
today.
What are the two important properties of
microscopes?
magnification and resolution

1.
2.
Magnification is the ability to make things look
larger.
The lenses in light microscopes magnifies an
object by bending the light that passes
through them.
In a compound microscope, light passes
through a specimen and then through two
lenses. The first lens magnifies the object,
and the second, magnifies it even more.
Microscopes Cont.
 The
ability to clearly distinguish the individual part
of an object is called resolution.
 Resolution is another term for sharpness of an
image.
 Electron microscopes use a beam of electrons
instead of light to produce a magnified image.
 Electron microscopes can obtain pictures of
extremely small objects, objects much smaller
than what can be seen with light microscopes.
Looking inside the Cell
 Organelles
are structures with in the cell that carry
out specific functions.
 The cell wall is a rigid layer of nonliving material
that surrounds the cells of plants and some other
organisms. The purpose of the cell wall is to
protect and support the cell. It is made of
cellulose and allows water and oxygen to easily
pass through.
Continuing through the Cell
 All
cells have a cell membrane. This controls
what substances come into and out of the cell. It
allows harmful waste products to leave the cell
and prevents harmful material from entering.
 The “control center” of the cell is the nucleus. It
acts as the brain, controlling all activity.
1. The Nuclear envelope protects the nucleus.
2. Chromatin are thin strands containing genetic
material that give instructions for directing the
cell’s function.
3. The nucleolus is within the nucleus and here is
where ribosomes (organelles where proteins
are produced) are made.
Organelles in Cytoplasm
 Cytoplasm
is the region between the cell membrane
and the nucleus.
 What is the “powerhouses” of the cell?


mitochondria
Why are mitochondria known as the “powerhouses” of
the cell?
 they
convert energy in food molecules to energy the cell
can use to carry out functions.
 Endoplasmic
reticulum are like of maze of passage
ways that carry proteins and other material from one
part of the cell to another.
 Ribosomes are grainlike bodies attached to the
surfaces of some endoplasmic reticulum. What is
function of ribosomes?

They are factories to produce proteins.
More Organelles in Cytoplasm
 Golgi
bodies look like flattened sacs and tubes.
The Golgi body can be thought of as a mail room.
They receive proteins, package them, and then
distribute them to other parts of the cell.
 Chloroplasts are only found in plant cells.
Chloroplasts capture energy from the sunlight and
use it to produce food for the cell.
 A vacuole is a water filled sac used as a storage
area for cells.
 The cell’s clean up crew are the lysosome. They are
small, round structures containing chemicals that
break down certain materials in the cell.
Special Cells
A
tissue is a group of similar cells that work
together to perform a special function. Tissues
form organs and organs form organ systems.

Example Brain
 Bacterial
cells are very different from plant and
animal cells. They are much smaller, have no
nucleus, contain genetic material in the
cytoplasm, and have ribosomes, but none of the
other organelles found in
plant or animal cells.