Cells Unit
Biome
 Ecosystem
 Community
 Population
 Organism
 Organ System
 Organs
 Tissue
 Cells
 Organelle
 Molecules

Discuss in Ecology
We will focus on
these areas
Properties of Life
1. Cellular Organization
2. Metabolism
3. Homeostasis
4. Growth & Development
5. Reproduction/Heredity
6. Responsiveness/Interaction
7. Evolution
Cells:
Organize
to form…
Tissues:
Collect &
work
together
to form…
Work
together
to form a
structure
that form…
Work together
to perform
major bodily
Functions.
Work with
others to
create an…
Organism
Organs:
Organ
Systems:
A
group of organs working together for a
particular function
A
defined group of tissues that work together
for one purpose
A
layer of the same
kind of cell
 The
basic unit of “living”
things.
=
a structure that carries out specific
activities in the cell.
 Groups
of atoms; the
smallest unit of most
chemical compounds
 Question:
What is a cell?
 Answer: the most basic unit of life that can
perform all life processes.
 Cells
are very small.
 Cells make up all living things (from
bacteria to elephants).
 They are the building blocks of all things
living.
 Cells
 But
can vary greatly in their size and shape.
they are all still very small.
 Just
how big are cells?
 Cell
size is limited for a reason.
http://learn.genetics.utah.edu/content/begin/cells/scale/
http://htwins.net/scale2/
This is the business end of a needle.
This one’s infested with E. coli.
Finger width
= 16mm
Bacteria
200µm = 0.2mm
Fig. 4-2a, p. 54
40µm = 0.04mm
Fig. 4-2b, p. 54
1µm = 0.001mm
Fig. 4-2c, p. 54
 Hooke
 Leeuwenhoek
 Virchow
 Schleiden
 Robert
Hooke in 1655.
 Looked at oak cork through a magnifying glass.
 Thought the compartments looked like the
rooms monks lived in…cells.
oil lamp
water
flask
specimen
focusing knob
Fig. 4-3b, p. 55
 Anton
van Leeuwenhoek (1660’s)
 Looked
at all kinds of stuff
through the first “microscope”.
 Called
what he saw
“animalicules”, which would later
be discovered to be bacteria.
 Schleiden
(1838)… Discovered cells in plants.
 Virchow (1858)… Was the first to discover
cellular division.

Microscope observations of
organisms led to the discovery of
the basic characteristics common to
all living things.

Scientists first discovered cells in
the 1600s using crude microscopes.

There has been many versions, the
most recent being very
sophisticated electron scanning
microscopes.
CELL THEORY:
 1. All living things are made up of one or more
cells.

This is universal. All living things are made of cells.
 2.
Cells are the basic units of structure and
function in organisms.

Just like amino acids are the basic unit of proteins,
cells are the basic unit of life.
 3.
All cells arise from other cells.
 If
cells are so small,
how do we see them?

We use microscopes.
 Cells
come in a variety of
shapes and sizes.


Some are very, very tiny like
bacteria
Some are relatively large like the
amoeba

All cells share 4 common features: Copy off the
board.
1.
The cell membrane is the outer layer that covers a
cell’s surface and acts as a barrier between the
outside environment and the inside of the cell.
The cytoplasm is the region of the cell within the
cell membrane. The cytoplasm includes the fluid
inside the cell called the cytosol.
A ribosome is a cellular organ that makes proteins.
The DNA of a cell provides instructions for making
proteins, regulates cellular activities, and enables
cells to reproduce.
2.
3.
4.
Prokaryotes
Eukaryotes

No nucleus
Prokaryotes

Nucleus
Eukaryotes
A
large membrane-enclosed structure that
contains the cell’s genetic information (DNA)
 Controls many of the cell’s activities
 Quick
definition: Genetic material (DNA) is
NOT contained in a nucleus
 More info: Generally smaller and less
complicated
 Examples include bacteria
 Are prokaryotes still living if they are less
complicated and microscopic? How do you
know this?
 Gram
positive organisms have a cell wall that
allows them to be stained to see.
 Some
bacteria don’t have a cell wall but they
can be stained with a different stain.
 When
you get sick a lab can run a test to see
if you have an infection and what kind of
infection you have.
B
Click to animate the image.
C
D
A
E
F
 Quick
definition: cells that store DNA in a
nucleus
 More info: inside these cells, parts are
separated from the rest of the cell by
membranes
 Examples: plants, animals, fungi, amoeba
 Look
for a nucleus!
Bacterial cell
Very basic
Animal Cell
Complex
More complex
100x bigger!
2 billion
years older!
Read each example and decide if it is a
prokaryote or a eukaryote.
1.
You scrape the inside of your cheek and
make a slide of the cells that come off.
2.
In an amoeba cell, there are many
complex cell parts and a membrane
wrapped around the DNA.
3.
A bacteria cell has a clump of DNA that
looks like a pile of spaghetti.
 1.
Eukaryote
 2. Eukaryote
 3. Prokaryote
 What
did you learn today?
Objective
Label common parts of an animal
cell and describe their functions
Warm-Up
What is the major difference
between a eukaryotic cell and a
prokaryotic cell?
Part II: Cell Organelle.
Cell wall
Cell membrane
DNA
cytoplasm
ribosome
flagella
 Controls
what moves in and out of a cell
REGULATOR!
 Protects
the cell and gives it shape
A
jellylike material that fills the cell
 Instructions
to run the cell. The “brain”.
 Helps
the cell move (one direction only)
 Follows
instructions to make proteins