“The Tiny Building Blocks of Life”
Why are cells nicknamed
“The Tiny Building Blocks of
Life?”
If you were to look at a tree and a
shark, you would not think that they
have much in common.
 However, if you looked closer, (at
their smallest parts) you would see
that they are very similar indeed.
 All organisms (living things) are
made up of cells.


Cells are the basic unit of function and
structure of living things.
 They are the tiny living things that make
up all the plants and animals on the
earth.
 Some plants and animals are made up
of only one cell! You can’t see those.
 To see plants or animals made up of
only one cell, you need to use a
microscope.
The Microscope


The microscope
makes the invisible,
visible!
Typical magnification
values are 4x, 5x, 10x,
20x, 40x, 50x and
100x.
The plants and animals that we see
are all made up of millions and
millions of cells!
 This is why we call cells “the tiny
building blocks of life.” See p. 26.


Guess what? Your own body is made
of more than a trillion cells! (That’s a
million millions!)

Organelles are the “organs” or parts
of a cell.
 They all have specific functions to
complete inside the cell so the cell
can survive.
 Let’s look at the organelles in an
animal cell…

http://waynesword.palomar.edu/lmexer1a.htm#plan
The job of the nucleus
is to be the “command
center” of the cell.
 It is the brain.
 It houses the DNA—
the personal
code/genes of an
organism that is unlike
any other.

The cell membrane
is like the “skin” of a
cell.
 It keeps all the
organelles inside
the cell and protects
them.

The cytoplasm is
held in place by the
cell membrane.
 It would be similar to
“glue” or “jello.”
 It holds all the other
organelles in place
inside the cell.

http://www.cellsalive.com/cells/cell_mo
del.htm

http://waynesword.palomar.edu/lmexer1a.htm#plan
Just like in animal
cells, the nucleus in a
plant cell works as
the brain.
 It controls the work
of all the other cell
organelles.


Just like in an animal
cell, the cytoplasm in
a plant cell is the
jelly-like fluid that
contains all the other
organelles.
The cell wall is like
the “skin” of a cell.
 It is a stiff cover that
protects and
provides support
and structure to the
cell.

Chloroplasts are like
the “solar panels” of
plant cells.
 The chloroplasts are
the green organelles
floating in the
cytoplasm.
 These are what makes
plants look green.
 The green chloroplasts
trap sunlight and make
food for the cell called
chlorophyll!

Compare and Contrast

Single-celled organisms
 Amoeba
 Bacteria

Multi-celled organisms
 Plants
 Animals
 People (You and me!)

Single-celled organisms are made up
of only one cell!
 Most are too small to be seen by the
naked eye (able to be seen without
any help from an eye instrument).
 To see these organisms, you have to
use a microscope.
Amoebas have no exact shape, they can
change their shape at will.
Amoebas are small, one-celled
microscopic creatures.
 They are hard to find because they
are transparent and look like
decaying organisms.
 They move by using
what scientists call
“false feet”. See? 


To eat, amoebas will surround their
prey (another small organism) with
their false feet and then engulf it.
1
2
Bacteria can grow in any
environment: underwater, in soil, in
nuclear waste, deep in the Earth’s
crust, ON plants and animals, and IN
plants and animals.
 There could be three types of
bacteria in your own body:

 Harmless
 Beneficial
 Harmful
A multi-celled organism is an
organism that consists of more than
one cell.
 Most living things that you can see
with your naked eye are multi-celled
organisms.


…Like you, and me, and your dog,
and the tree outside!!
Your own body is many different cells
that all do many different jobs.
 Let’s see how cells really do become
“the building blocks of life” for you!

•Cells form tissues (like muscle tissue).
Tissues form organs (like
the heart and stomach).
•Organs form systems.
•For example: the
digestive system is
formed from the
tongue, stomach, and
intestines working
together.
Organ systems form organisms.
 All your organ systems working
together make you work! (You have
eleven working together in all.)

Cells
Tissues
Organs
Organ Systems
Organisms

http://www.kbears.com/sciences/mic
roscope.html

http://www.cellsalive.com/cells/cell_
model.htm

http://classroom.jc-schools.net/sciunits/cells.htm#5