Unit IV:
Cell Structure & Transport
Part 1 – Cell Structure
Hierarchy of Cell Structure

Cells
 Organelles
 Mixtures
 Compounds

Atoms/Elements
Cell Discoveries…

How a cell came to be called a “cell”…
Cell Discoveries…

Microscope man…
Cell Theory

1. All living things are made of cells


2. All cells come from other cells


Any exceptions?
Where did the first cell come from?
3. Cells are the basic units of life

Meaning?
Cell Theory

1. All living things are made of cells


2. All cells come from other cells


Schleiden – plants + Schwann – animals = ALL
Virchow – cell reproduction
3. Cells are the basic units of life

Meaning?
Cell Structure - Typical Cell?
Most cells contain
same organelles
and compounds,
but,
cells are NOT
identical in
structure
(appearance)
Cell Structure & Function


The job fits the parts!
This applies to shape of cell & organelles in it

Structure and function go hand-in-hand for all
parts of living things…including cells
Depending on what the cell’s job, it must be
structured differently than a “typical cell”
 For example…

Neurons: carry electrical messages
How related to its structure?
Neurons: carry electrical messages
- have many branches & are long…allows
them to communicate better
Muscle cells contract to cause movements
How related to its structure?
Muscle cells contract to cause movements
- are very long…allows them to contract
Respiratory lining cells have cilia (tiny hairs)
How related to function?
Respiratory lining cells have cilia (tiny hairs)
- cilia move mucus along tube
Cell Types: The Prokaryotic Cell



No nucleus; single circular
chromosome
No membrane-bound organelles
Ex: bacteria
~ cell wall (peptidoglycan)
~ some with flagella
~ no specific spot for DNA
pro = first; before
kary – kernel; nucleus
Cell Types: The Eukaryotic Cell




Has membrane-bound
nucleus that holds DNA
Has “fancy” organelles
Usually larger in size
Ex: everything EXCEPT
bacteria
Eu – good
Cell Types: Plant Cell
~ cell wall (cellulose)
~ chloroplasts
~ large central vacuole
~ NO centrioles
~ NO cilia or flagella
Cell Types: Animal Cell
~ NO cell wall
~ NO chloroplasts
~ small vacuoles
~ centrioles
~ may have cilia or flagella
POP Quiz – Cell Structure

1. Which of the following are prokaryotic cells?
A. plants

B. animals
C. fungi
D. bacteria
2. If a particular cell has a cell wall, it is unlikely
to contain A. centrioles B. ribosomes C. chloroplasts D. DNA
POP Quiz – Cell Structure

3. Prokaryotic cells will NOT contain a A. cell wall B. cell membrane C. nucleus D. flagellum

4. Animal cells are easily distinguished from
plants because they lack a A. cell wall B. cell membrane C. nucleus D. flagellum
POP Quiz – Cell Structure

5. All of the following structures can be found in
ALL cell types, EXCEPT A. cell membrane
B. mitochondria

C. DNA
D. ribosomes
6. Schleiden’s contribution to the cell theory was
that A. All animals are made of cells
B. All cells come from preexisting cells
C. All plants are made of cells
D. None of the above
POP Quiz – Cell Structure

7. Bob finds something in his yard and wonders if it
is living or nonliving. Which of the following would
be the best evidence that it is living?
A. It moves
B. It gives off heat

C. It contains cells
D. It gives off water
8. Which of the following is NOT a part in the cell
theory?
A.
B.
C.
D.
All organisms are made of cells
Cells are all the same shape and size
Cells are the basic unit of life
All cells come from preexisting cells
Endosymbiotic theory
Cell Structures
(refer to your cell diagrams)

Cell wall

Tough covering…provides structure & protection;
animal cells do not have these
Cell Structures
(refer to your cell diagrams)

Cell Membrane


Lipid bilayer; controls cell
homeostasis & transport
Cytoplasm

Water-based fluid;
contains dissolved
substances
Cell Structures

(refer to your cell diagrams)
Cytoskeleton

Fibers that form framework of cell
Cell Structures
(refer to your cell diagrams)

Nucleus


Membrane-bound…
contains DNA; controls
cell activities
Nucleolus

Spot within nucleus;
deals with RNAs
Cell Structures
(refer to your cell diagrams)

Endoplasmic Reticulum (ER)



“highway system”; chemicals made by cell travel thru
this
Rough ER – holds ribosomes (makes proteins)
Smooth ER – site of lipid synthesis
Cell Structures
(refer to your cell diagrams)

Ribosomes

Site of protein synthesis; may be “free” or bound
to rough ER
Cell Structures
(refer to your cell diagrams)

Golgi Apparatus


“post office”; packages & sends out chemicals
Flattened sacs stacked on each other
Cell Structures
(refer to your cell diagrams)

Mitochondria

Membranous; turns glucose into energy molecules
(ATP)

All eukaryotic cells have these
Cell Structures
(refer to your cell diagrams)

Chloroplast


Membranous; contains chlorophyll
turns light & CO2 into glucose
Cell Structures
(refer to your cell diagrams)

Vacuoles


Storage vesicles
Central vacuole – in
plants; very large
Cell Structures
(refer to your cell diagrams)

Lysosomes

Contain digestive enzymes; “eat” substances
Cell Structures
(refer to your cell diagrams)

Peroxisomes

Contains enzymes that detoxify chemicals
Cell Structures
(refer to your cell diagrams)

Centrioles

Used to make fibers for mitosis
Cell Structures
(refer to your cell diagrams)

Flagella


Tail-like structure; moves cell
Cilia

Hair-like structures; move
cell or fluids in cell
environment
Cell Structures
(refer to your cell diagrams)

Microvilli

Finger-like extensions; increase surface area
Endosymbiont Theory
Mitochondria & chloroplasts are thought to
have come from ancient prokaryotic cells
Evidence: Both mitochondria and chlorplasts…
 have their own DNA
 have their own ribosomes
 have membranes similar to bacteria
 divide like bacteria (binary fission)

Recap - Cell Structure
Eukaryotic cells are much more complicated than
prokaryotic cells, but all cells have:
cell membrane, cytoplasm, DNA,
ribosomes, & cytoskeleton
What is so critical about each of these that ALL cells
have them?
Unit IV:
Cell Structure & Transport
Part 2 – Cell Transport & Homeostasis
Cell Membrane
phospholipids: the main ingredient of the cell
membrane; they have polar side & nonpolar sides
Which side of the molecule “likes” water?
How does that relate to the way it must face?
Cell Membrane:
controls what goes in/out

Structure:
 fluid-mosaic model
 molecules stick to each
other, but able to move
 phospholipid bilayer:
~ polar (hydrophilic)
…faces outward
~ nonpolar (hydrophobic)
…faces inward
non = not
phil = love
phob = fear
bi - two
Cell Membrane:
controls what goes in/out

Structure:




integral proteins help with transport
cholesterol keeps it fluid
glycoproteins act as “ID tags”
receptors react to chemicals
Cell Membrane:
controls what goes in/out
What is the
purpose of…
Glycolipids &
Glycoproteins?
Cholesterol?
Integral
proteins?
12. What is the
function of the
cell membrane?
11
10
1
13. What are the
three parts of the
cell theory?
2
3
4
5
9
8
7
6
14. What is the
function of the
nucleus?
15. What is the
difference
between a
prokaryote and
eukaryote?
Cell Transport

Active Transport –
requires energy; moves
against concentration
gradient (low to high) or
involves large particles


1. endocytosis – “traps”
stuff & brings in
2. exocytosis – releasing
stuff to outside
Cyto - cell
Cell Transport

Passive Transport –

no energy required; moves with concentration
gradient (high to low)
Cell Transport

Passive Transport

1. diffusion – move from high to low concentration until
equilibrium is reached
Cell Transport

Passive Transport
 2. osmosis- diffusion of water through selectively
permeable membrane (like cell membrane)
Typically, water can
move freely in/out
of membrane but
solutes (like
glucose) cannot
Water moves to try
to equal out the
concentrations on
both sides

Hypotonic – lower concentration of solute


Hypertonic – higher conc. of solute


Ex: distilled water is pure water…it would be
hypotonic to cells (and everything else!)
Ex: the Dead Sea is very salty…it would be
hypertonic to cells
Isotonic – equal conc. of solute
Osmosis:
water moves to the side with more “stuff”

What happens if a cell is placed in an
environment that has a low solute
concentration?


Where is there more “stuff”?
What will the result be?
Hypo – below
Osmosis:
water moves to the side with more “stuff”

What happens if a cell is placed in an
environment that has a high solute
concentration?


Where is there more “stuff”?
What will the result be?
Hyper – above; over
Osmosis:
water moves to the side with more “stuff”

What happens if a cell is placed in an
environment that has an equal solute
concentration?


Where is there more “stuff”?
What will the result be?
iso – equal
Cell Transport

Passive Transport

3. facilitated diffusion- like diffusion, but
with “helper” molecule (larger molecules like glucose
need this)…still goes high to low
The End
LAB – Osmosis in Potato Cells

I. PURPOSE


How will potato cells react when placed in
hypertonic or hypotonic solutions?
II. BACKGROUND


Hypertonic solutions have more “stuff” dissolved.
Hypotonic solutions have less “stuff” dissolved.
LAB – Osmosis in Potato Cells



III. HYPOTHESES
 Potato cells in hypertonic solution will ___
 Potato cells in hypotonic solution will ___
IV. PROCEDURE (draw pic)
V. DATA
SALT
MASS (g)
MASS (g)
CONC (%)
0% (Hypo)
10% (Hyper)
Initial
Final
MASS
Difference
LAB – Osmosis in Potato Cells

VI. CONCLUSION



What happened in set-up? Explain why it
happened.
Does this support OR not support your hypotheses.
Describe 2 sources of error related to this lab.
Highlight these in your notes…




Passive Transport
Diffusion
Osmosis
Facilitated diffusion








Active transport
Endocytosis
Exocytosis


Phospholipid bilayer
Fluid mosaic
Cholesterol
Glycolipid (-protein)
Channel/helper protein
Integral protein
Peripheral protein
Highlight these in your notes…



Prokaryotic
Eukaryotic
Endosymbiont theory



Mitochondria
Chloroplasts
Cell theory




Cell membrane
Ribosome
Cytoplasm
DNA/chromosome
Highlight these in your notes…
ALL CELLS…
Cell membrane
Ribosome
Cytoplasm
DNA/chromosome






Cell
wall
Flagella (cilia)


EUKARYOTES only…
Rough ER
Smooth ER
Golgi
Mitochondria
Chloroplast
Lysosome
Nucleus
Quiz – Cells #2
 Answer
on your own paper.
 You do NOT need to write the
questions.
Quiz – Cells #2

1. Name the parts. Choices…
helper protein – peripheral protein - phospholipid
glycoprotein – glycoprotein - cholesterol
Quiz – Cells #2

2. Describe the function of each part of
the cell membrane.
A. helper protein
B. glycoproteins
C. cholesterol
Quiz – Cells #2
3. Why does it have to be a LIPID layer
that makes up the cell membrane?
 4. Why does it have to be a BILAYER (2
layers) for the cell membrane?
 5. Which part “loves”
water? A
………..or B

Cell Size Limits
What is the lower limit of
cell size determined by?
~ is set by having enough
DNA to code metabolism,
do metabolism, and
reproduce
Cell Size Limits
What is upper limit set by?
Upper limit is set by surface
area to volume ratio
~Must be enough plasma
membrane (SA) to allow fast
enough transport rate to supply
entire cytoplasm (volume) with
chemicals
Cell Size Limits
As cell
enlarges,
volume
increases
faster than
surface area