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Chapter 8

A Tour of the Cell
How can we see cells?

Light microscope
–

Not
Uses light and lenses to magnify
Electron microscope
–
–
Uses beam of electrons
Gives a 3-D picture
a flashcard.
Electron vs. Light
Not
a flashcard.
What can you see without a microscope?
View the size of cells
Not
a flashcard.
Here are some pictures of cells
Cell Types
Bone
Cell
Cartilage
Cell
Not
Muscle
Cell
Blood
Cell
a flashcard.
Nerve
Cell
Small
Intestine
Cell
Discovery of the Cell
Made possible by the development of the
microscope
 Robert Hooke first used a microscope in
1665

 Examined
a thin slice of cork
 Found similar formations, “a great many little
boxes,” when looking at stems of trees, carrots, and
ferns
 Cells – named after the small rooms in which monks
lived
Cork cells
Not
a flashcard.
Cell Theory
The 3 Parts to the Cell Theory:
All living things are composed
of one or more cells
Cells are the basic units of life
All cells come from pre-existing
cells
There are 2 types of cells
Prokaryotic
Example: bacteria
Eukaryotic
Examples: plant & animal
Which is Bigger?
Bacteria Cell
Animal Cell
Small
Bigger
Not
a flashcard.
Plant Cell
Biggest
Cell Type: Prokaryotic
 No
true nucleus
 No organelles
with membranes
Cell Type: Eukaryotic
 Has
at least 1
true nucleus
 Has
organelles
with membranes
Prokaryotes vs. Eukaryotes
Why aren’t cells large?

As cell size

Rates of chemical exchange may then be
inadequate for cell size
 Cell
, the surface area to volume ratio
size, therefore,
remains small
Not
Cell Size
a flashcard.
Not
a flashcard.
• Surface
A small cellArea
has a greater
ratio of surface
to Volume
Ratioarea
to volume than a large cell of the same shape
30 µm
Figure 4.3
Surface area
of one large cube
= 5,400 µm2
Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings
10 µm
Total surface area
of 27 small cubes
= 16,200 µm2
Unicellular vs. Multicellular
Unicellular
Made of only ONE cell
or
Multicellular
Made of more than one cell
Organelles


There are 16
organelles I
would like you to
know. 
Be able to label
each of them and
describe their
functions.
Not
a flashcard.
Cell Wall
Not
in
animal cells
Provides:
protection
shape
support
Cell Membrane



Made of phospholipids
Selectively permeable
Maintains homeostasis
The Cell Membrane…
Not
a flashcard.
Controls what enters and leaves the cell
Cytoplasm
 Clear
fluid
that surrounds
the organelles
 Jelly-like
The Cytoskeleton



Fibrous network in cytoplasm
Provides support and maintains shape
Made of microtubules
Nucleus
The cell’s control
center
 Contains DNA
 RNA is made here

Nucleolus
Inside
the
nucleus
Produces
ribosomes
Mitochondria
Makes energy
 The more
mitochondria, the
more energy the cell
can produce!
(muscle cells)

Endoplasmic Reticulum
A folded membrane
attached to the nucleus
 ‘Intra-cellular highway’

Ribosomes


Small and ‘circular’
Assembles amino acids to make proteins
Vessicles
 Small
packages
that transport
proteins from
the ER to the
Golgi apparatus
Golgi Apparatus


Flattened sacs
Packages proteins and lipids to leave the cell
Lysosomes
 sacs
of enzymes
 digests particles
Vacuoles


Stores food, enzymes,
and waste
Plants: only 1 LARGE
Chloroplasts
Found only in plants
 Contains chlorophyll (green)
 Converts sunlight to useable energy

Elodea Cells
Not
a flashcard.
Centrioles


Used in cell replication; only in animal cells
Pulls chromosomes apart
Cilia vs. Flagella
Locomotive appendages:

Cilia is short and
hairlike (large #’s)

Flagella is longer
and whiplike
(small #’s)
Real Pictures of Cilia
Not
a flashcard.
It’s all connected!
Not
a flashcard.
Difference Between Plant & Animal Cells
Plant Cells Have:
 A Cell wall
 Chloroplasts
 Larger vacuole
 No centrioles
A Plant Cell
Not
a flashcard.
A Real Plant Cell
Not
a flashcard.
Another Plant Cell
Not
a flashcard.
Important
Info!
An Animal Cell
Not
a flashcard.
Another Animal Cell
Not
a flashcard.
Cell Cheer!
 The End! 
See you
soon!