Chapter 4 - Cell Structure and Function
The printed out notes are more detailed than these slides, you are expected to read the chapter and
your notes - anything is fair game on the test, but the cell chapter is largely review.
Lab: microscopes and membranes
Thurs: 10/9
A. The Cell Theory
1. Every living organism is
made of one or more cells.
2. The cell is the basic unit
of structure and function. It
is the smallest unit that
can perform life functions.
3. All cells arise from preexisting cells.
*Why is the Cell Theory
called a Theory and not
a Fact?
Cells need a large surface area to volume ratio
If there a person was at
the very center of each
house and accidently
started a fire, the
person in which house
would have a better
chance of escaping?
Figure 4.3
Early Contributions
Hooke
Leeuwenhoek
Schleiden
Schwann
Virchow
http://htwins.net/scale2/
B. ALL CELLS HAVE:
1. Cell Membrane
a) Phospholipid Bilayer (double layer)
b) Proteins
c) Carbohydrates
2. Genetic Material
3. Cytoplasm (cytosol)
ORGANELLES float
within cytoplasm and
perform specific
functions
Prokaryote Cells
Figure 4.4a
Eukaryotes
Endosymbiosis :
All organelles seem to share many properties with
bacteria. Lynn Margulis proposed:
endosymbiosis hypothesis: that ancient
colonization of large bacteria (became the
eukaryotic cell) engulfed smaller bacteria
(became the mitochondria, chloroplast, etc.)
Symbiosis = "living together".
*Mitochondria & Chloroplasts have their own DNA
Animation at Microbiological Concepts
https://www.youtube.com/watch?v=3ESXvLHceDc
Endosymbiosis Theory
that ancient colonization of large
bacteria (became the eukaryotic
cell) engulfed smaller bacteria
(became the mitochondria,
chloroplast, etc.)
http://www.youtube.com/watch?v=-FQmAnmLZtE
In your notes:
Create a diagram comparing prokaryotic and
eukaryotic cells. Include examples of each and
anything you can remember
When done, use ch 4 to label the pictures on your notes outline handout
pg 65 and 68
Prokaryote
No
Organelles
Simple
Mostly
single
cells
Archaea
and bacteria
both
Cells
DNA
Cytoplasm
Plasma
Membrane
Ribosome
Cell wall
Eukaryote
Membrane
Bound
Organelles
Nucleus
Complex
Specific in
function
Multicellular
Plants,
Animals,
fungi
Quick Recap.......
1. What are the two main types of cells?
2. Which one is larger?
3. Which one does not have a membrane bound nucleus?
4. What are the three main parts of the cell (that all cells
have)?
5. What are the 3 components of the cell theory?
6. What theory best explains how eukaryotes evolved?
Label the pictures on the top of your notes outline: use 65, 68-69 to help
Prokaryotic or Eukaryotic?
1
2
1. Has membrane bound organelles
2. Includes plant and animals cells
3. Bacteria P
4.
E
5.
P
6. Has no organelles
P
E
E
cell biology is a huge area, and is divided into many branches
that biologists specialize in...
1) Oncology
2) Microbiology
3) Genetics
4) Paleobiology
5) Pathology
............to name a few
Here's an older video that compares prokaryotes and
eukaryotes and discusses how cells evolved, film by the
Phoenix Learning Group (17 minutes)
And a shorter video on the main parts of The Cell
The Parts of the Cell
Cell Diagram Directions:
1. You will get a picture of a animal or plant cell,
label the cell.
2. label as many parts as you can remember
3. Then look in your book to label the rest
4. Write a 2-5 word description of the function of
each part
II. Nucleus:
• Nucleoplasm: semifluid
matrix
• Chromatin: uncoiled, fluid
DNA and proteins
• Chromosomes: coiled,
rodlike DNA structures
• Gene: unit of heredity
located on DNA
• Nucleolus: dark region of chromatin where rRNA
joins with proteins to form ribosomal subunits (parts
to make ribosomes)
• nuclear envelope contains nuclear pores for some
things to enter and exit
III. Endomembrane System:
Includes:
a.Nuclear
envelope
b.Membrane
of the ER
c.Golgi
apparatus
d.Several
types of
lysosomes
I am a reticulated python. Ask me what I have to do with the endoplasmic
reticulum.
A. Nuclear Envelope/ Membrane: RNA leaves nucleus to
instruct production of proteins
B. Endoplasmic Reticulum
(endoplasm= "within
cytoplasm", reticulum= "little
net"
--divides cell into
compartments
--channels molecules through
the cell's interior, like a little
highway, make vesicles
Figure 4.10a
Rough ER
--has ribosomes
--functions in
protein synthesis
-- ER transports newly assembled proteins to the Golgi
Apparatus
Smooth ER
--no ribosomes
--mostly contains enzymes that act in lipid synthesis (such as
hormones like estrogen and testosterone)
Vary depending on location
C. Golgi Apparatus: Delivery System
-flattened stacks of
membranes
-functions in collection,
modifying, packaging
and distribution of
molecules made in the
cell and used
elsewhere
-unprocessed proteins
enter the front end
(cis) near the ER, and
are exported near the
cell membrane, at the
back end (trans)
--the folded stacks are called cisternae
Jobs of the Golgi
Apparatus (aka Golgi
Complex)
1. separates proteins
according to their
destinations
2. modifies proteins (adds
sugar and makes
glycoproteins)
3. packages materials into
vesicles which are exported
outside the cell - secretion
Lysosomes - Intracellular Digestion Centers
--contain high levels of degrading enzymes (to "lyse" means
to dissolve)
--recycle old and worn out cell parts - apoptosis "suicide
sac”
-digest other particles taken in by phagocytosis
--this "food" is stored in food vacuoles, the lysosomes fuse
with the vacuoles and release digestive enzymes
Lysosomes - Intracellular Digestion Centers
TAY-SACHS disease – What do lysosomes have
to do with this deadly disease?
Article and Video on Tay Sachs http://6abc.com/archive/9036458/
https://www.youtube.com/watch?v=RzEpkBU-ITA
Tay-Sachs disease is caused by the absence or significantly reduced
level of a enzyme called beta-hexosaminidase (Hex-A). Normally, Hex
A is a digestive enzyme that is part of the lysosome.
Without the correct amount of the Hex-A enzyme, a fatty substance or
lipid called GM2 ganglioside accumulates abnormally in cells,
especially in the nerve cells of the brain.
Ribosomes - Sites of Protein Synthesis
-each is composed of two
subunits, one large and
one small
-mRNA is "read" by the
ribosomes and amino
acids are assembled into
proteins
-ribosomes are
manufactured by the
nucleolus, assembles by
ER
--polyribosomes – strings of ribosomes in the
cytoplasm that work to make a protein
Free vs Bound Ribosome
Free ribosomes: produce proteins that are used by the cell.
- ex: for metabolism of food.
Bound ribosomes: produce proteins that are transported out of
the cell.
- ex: for a specific function, such as digestive enzymes
and polypeptide hormones.
Mitochondria
--contains its own DNA,
support for Endosymbiosis
Theory
• mitochondria divide
before cell division, they
are not synthesized like
other cell parts
--function: store energy for
cell use. Energy is stored in
the form of ATP adenosine triphosphate
-2 membranes, one smooth outer membrane, and an inner
membrane folded into layers called cristae
--Cristae has two compartments: the matrix and the
intermembrane space
What happens if your mitochondria don’t work?
Mitochondrial Disease Video
Why is mitochondrial disease
so devastating to children?
Consider the mitochondria
have their own DNA separate
from the parental DNA. How
could you cure this disease?
https://www.youtube.com/watch?v=6_ylLEhRG30
Focus on Plant Cells
Chloroplasts - Where Photosynthesis Takes Place
Plants only
--has its own DNA, like
mitochondrion
--functions: to convert
light energy to
carbohydrates
--carbohydrates then
broken down in
mitochondria to
produce ATP
Parts of chloroplast
--thylakoids are the individual disk shaped compartments
-- Grana: stack of thylakoids
--stroma is the fluid surrounded the thylakoids
*Chloroplasts are a
type of plastid
Chromoplasts –
red, yellow and
orange pigment
Leucoplasts –
colorless (potatoes)
Cytoskeleton- support system
a. Microfilaments (now called actin filament) – occur in bundles,
form tracks within the cell for the movement of organelles, used to
form pseudopods (ameba)
b. Intermediate filaments - support membrane, cell to cell
junctions
c. Microtubules - (little pipe) radiate from the centrosome - form
the spindle during cell division
Centrioles – used during cell
division to move and separate
chromosomes, only found in
animal cell
Cytoskeleton
How do cells maintain their shape?
How do they move?
- pseudopod
- cilia
- flagella
Pseudopod – extensions of the cell that allow for
movement (ameba), depend on actin filaments
Cilia (hair) & Flagella (whip)
--function in movement
-- 9 + 2 Arrangement of microtubules
http://www.youtube.com/
watch?v=7pR7TNzJ_pA
Hey....remember enzymes?
The Peroxisome
Found in plant and animal cells, this organelle
plays a critical role in normal cell functioning.
In human cells, peroxisomes house
some
sixty enzymes, involved in
metabolic processes such as bile acid,
cholesterol, and plasmalogen biosynthesis, as
well as ß-oxidation
peroxisome produces hydrogen peroxide as a
by-product of its normal function.
-To neutralize this potentially toxic compound,
a peroxisome imports the hydrogen peroxidemetabolizing enzyme catalase, from the
cytosol of the cell. Catalase converts hydrogen
peroxide to water and oxygen
Vacuole
-- mainly storage or specific functions
(contractile vacuole, fat vacuole)
-- Plant cells have a CENTRAL VACUOLE - used for storage
and help to maintain hydrostatic pressure
QOD:
1. What does the cell theory state?
2. Explain why cells are so small using the idea surfacearea- to- volume ratio.
3. Compare and contrast plant and animal cells
use a graphic organizer: (venn, tree map, etc)
•Plant Cell
•Animal cell
•Eukaryote
•Plasma Membrane
•Nucleus
•Ribosome
•ER
•Mitochondria
•Chloroplast
•Cell wall
•Cytoplasm
•Golgi Apparatus
•Vacuole
•Centrioles
•Fern Cells
•Muscle Cells
•Human Cells
Plant
Animal
Tree Map
Double Bubble (like a venn diagram)
Cell wall
Eukaryote
vacuole
centrioles
Nucleus
Mitochondria
Plant Cell
Chloroplast
Fern
Cytoplasm
Animal Cell
Muscle
cells
Plasma
Membrane
Ribosome
ER
lysosome
Golgi apparatus
humans
Eukaryote
Plant Cell
Animal Cell
vacuole
centrioles
Nucleus
Cell wall
Chloroplast
Fern
Mitochondria
Muscle
cells
Cytoplasm
Plasma
Membrane
Ribosome
ER
lysosome
Golgi apparatus
humans
QOD: Proteins in the Cell
What parts of the cell are involved with protein
production and what role does each part play?
Most of the
Endomembrane:
• Nucleolus
• Rough ER
• Golgi
• Vesicles
• Free Ribosome
Mini Quiz
1. What part of the cell
produces vesicles for export?
2. What part of the cell makes
proteins?
3. What part of the cell
produces ATP?
4. What part of the cell
transports materials throughout
the cytoplasm?
5. What part of the cell has a
cis and a trans face?
https://www.youtube.com/watch?v=1Z9p
qST72is&feature=youtu.be
a. ________________
b. ________________
c. _________________
d. _________________
e. _________________
f. __________________
f.
Find the:
a. Nucleolus
b. Centriole
c. Vesicle
d. Smooth
ER
e. Lysosome
Figure 4.7b
What is this structure?
What is this structure?
Terms / Concepts for Show, Don't Tell
cell_theory
mitochondria
chloroplast
prokaryote
protein_synthesis
eukaryote
nucleus
lysosome
ribosome
endoplasmic_reticulum
cytoskeleton
golgi_apparatus
enzyme
messenger_RNA
chromatin
phospholipid_bilayer
cilia
flagella
microscope
peroxisome
Single Cheek Cell - at different illuminations