Cellular Transport

1
Cellular Transport
2
Transportation of
Substances Across a Cell's Membrane
BEFORE WE CONTINUE ON WITH MOVEMENT BETWEEN
CELLSIT IS IMPORTANT TO KNOW ABOUT THE DIFFERENT
TYPES OF CELLS THAT EXIST!
3
Types of cells

• PROKARYOTES
• -UNICELLULAR
• -ARE THE LARGEST GROUP OF ORGANISMS
• -SIMPLE STRUCTURE
• -NO NUCLEUS
• -NO MEMBRANE BOUND ORGANELLESwait what is an
  organelle?
• -APPEARED ABOUT 4 BILLION YEARS AGO- most
  primitive
• EXAMPLE bacteria

• EUKARYOTES
• -MORE ADVANCED
• -ALL CELLS IN MULTICELLULAR ORGANISMS ARE
  EUKARYOTES AND SOME IN UNICELLULAR ORGANISMS.
• - HAVE NUCLEUS
• -HAVE MEMBRANE BOUND ORGANELLES
• -COMPLEX INTERNAL STRUCTURE
• - APPEARED ABOUT 1 BILLION YEARS AGO
• EXAMPLE fish, humans, paramecium

4
PROKARYOTIC CELLS
No membrane bound nucleus. Instead, genetic info
is in the nucleoid or a circular loop called a
plasmid!
Since you are more familiar with the eukaryotic
cells from the cells unit, lets look at bacteria,
prokaryotes.
Bacteria cells are very small- like the size of
an animal cells mitochondria
Prokaryotes feature 3 major shapes rods,
spherical, and spiral
5
PROKARYOTIC CELLS
Bacteria serve as decomposers, act in the
nitrogen cycle, are agents of fermentation, and
play an important role in our own digestive
system. But they can also make us SICK! ?
6
PRO OR EUK
EUK EUK EUK PRO PRO EUK PRO

• Snake cells
• Human cheek cells
• Venus fly trap plant cells
• Blue-green algae (cyanobacteria)
• E.Coli
• Salmon cells
• Salmonella Bacterium cells

7
. HOW THE EUKARYOTE FORMED FROM THIS FIRST BASIC
PROKARYOTE
Mr. Phagocyte Yum.Bacterium Excuse me.Mr.
Phagocyte What?Bacterium You know, why don't
we join forces and I can help you and you can
help me and we can become a 'eukaryotic' cell?
Whaddaya say?Mr. Phagocyte OK
Prokaryote
8
PROKARYOTE
EUKARYOTE
WITHOUT membrane bound WITH membrane
organelles bound organelles
9
And now back to our scheduled program on.
CELL TRANSPORT

• With your table partner try to answer these
  questions
• What structure do things need to get past in
  order to get in or out of cells?
• Would it be easier for you to get to a place
  walking with the wind or against the wind?
• What might be needed to cross into and out of
  cells? What might be needed to get into a cell
  or out of a cell?

10

• With your table partner try to answer these
  questions
• What structure do things need to get past in
  order to get in or out of cells?
• 2. Would it be easier for you to get to place
  walking with the wind or against the wind?
• 3. What might need cross into and out of cells?
  What might need to get into a cell or out of a
  cell?

Cell Membrane
With the wind...it would help you move and push
you so you would not have to use as much energy
Food, nutrients, bacteria, viruses, other cells
like the sperm going into the egg cell
11
THINGS NEED TO PASS THROUGH THE Cell Membrane
DOUBLE LIPID LAYER
The cell membrane is made up a ___________________
_______. Phospholipids have a head that is
attracted to water _____________________ and a
tail that repels water ___________.
HYDROPHOBIC
HYDROPHILIC
12
In the cell, there are 2 layers of phospholipids.
As you can see in the drawing below, the 2
layers of lipids have the heads facing outward
toward the water, and the tails facing inward
where there is no water. This double layer of
phospholipids forms a tough yet flexible
_________________.
MEMBRANE
13
About Cell Membranes

• All cells have a cell membrane
• Functions
• Controls what enters and exits the cell to
  maintain an internal balance called homeostasis
• Provides protection and support for the cell

TEM picture of a real cell membrane.
14
About Cell Membranes (continued)

• Structure of cell membrane
• Lipid Bilayer -2 layers of phospholipids
• Phosphate head is polar (water loving)
• Fatty acid tails non-polar (water fearing)
• Proteins embedded in membrane

Phospholipid
Lipid Bilayer
15
Protein channels
Also located within the lipid bilayer are
____________________ and ____________________
chains..
carbohydrates
The proteins can act as channels or pumps. They
also identify your cells and sometimes act as
receptor sites.
The carb chains identify the cell as belonging to
you. They are like little labeling flags.
If a cell enters your and has different
carbohydrate chains, the white blood cells will
attack them because they are foreign invaders of
your body. This is how cells fight infection
16
Fluid Mosaic Model of the cell membrane
Polar heads love water dissolve.
Membrane movement animation
Non-polar tails hide from water.
Carbohydrate cell markers
Proteins
17
About Cell Membranes (continued)

• 4. Cell membranes have pores (holes) in it
• Selectively permeable Allows some molecules in
  and keeps other molecules out
• The structure helps it be selective!

Pores
18
Structure of the Cell Membrane
Outside of cell
Carbohydrate chains
Proteins
Lipid Bilayer
Transport Protein
Phospholipids
Inside of cell (cytoplasm)
Animations of membrane structure
Go to Section
19
CONCENTRATION GRADIENT
A situation in which particles are highly
concentrated in one area and in low concentration
elsewhere.
20
Types of Cellular Transport

• Animations of Active Transport Passive Transport

• Passive Transport
• cell doesnt use energy
• Diffusion
• Facilitated Diffusion
• Osmosis
• Active Transport
• cell does use energy
• Protein Pumps
• Endocytosis
• Exocytosis

21
Passive Transport

• cell uses no energy
• molecules move randomly
• Molecules spread out from an area of high
  concentration to an area of low concentration.
• (High?Low)
• Three types

22
PASSIVE TRANSPORT Movement of small particles
across a membrane WITHOUT USING ENERGY!
Types of Passive Transport
DIFFUSION Random movement of particles from areas
of high to low concentration
FACILITATED DIFFUSION Allows larger particles to
get through by using protein channels
OSMOSIS THINK H2O-smosis Movement of water from
high to low concentration
23
Passive Transport 1. Diffusion
Simple Diffusion Animation

• Diffusion random movement of particles from an
  area of high concentration to an area of low
  concentration.
• (High to Low)
• Diffusion continues until all molecules are
  evenly spaced (equilibrium is reached)-Note
  molecules will still move around but stay spread
  out.

http//bio.winona.edu/berg/Free.htm
24
Passive Transport 2. Facilitated Diffusion
A
B

• 2. Facilitated diffusion diffusion of specific
  particles through transport proteins found in the
  membrane
• Transport Proteins are specific they select
  only certain molecules to cross the membrane
• Transports larger or charged molecules

Facilitated diffusion (Channel Protein)
Diffusion (Lipid Bilayer)
Carrier Protein

• http//bio.winona.edu/berg/Free.htm

25
Passive Transport 2. Facilitated Diffusion
Glucose molecules
Cellular Transport From a-
High
High Concentration

• Channel Proteins animations

Cell Membrane
Protein channel
Low Concentration
Low
Transport Protein
Through a ?
Go to Section
26
Osmosis animation
Passive Transport 3. Osmosis

• 3.Osmosis diffusion of water through a
  selectively permeable membrane
• Water moves from high to low concentrations

• Water moves freely through pores.
• Solute (green) to large to move across.

27
Effects of Osmosis on Life

• Osmosis- diffusion of water through a selectively
  permeable membrane
• Water is so small and there is so much of it the
  cell cant control its movement through the cell
  membrane.

28
Hypotonic Solution

• Osmosis Animations for isotonic, hypertonic, and
  hypotonic solutions

Hypotonic The solution has a lower
concentration of solutes and a higher
concentration of water than inside the cell. (Low
solute High water)
Result Water moves from the solution to inside
the cell) Cell Swells and bursts open
(cytolysis)!
29
Hypertonic Solution

• Osmosis Animations for isotonic, hypertonic, and
  hypotonic solutions

Hypertonic The solution has a higher
concentration of solutes and a lower
concentration of water than inside the cell.
(High solute Low water)
shrinks
Result Water moves from inside the cell into
the solution Cell shrinks (Plasmolysis)!
30
Isotonic Solution

• Osmosis Animations for isotonic, hypertonic, and
  hypotonic solutions

Isotonic The concentration of solutes in the
solution is equal to the concentration of solutes
inside the cell.
Result Water moves equally in both directions
and the cell remains same size! (Dynamic
Equilibrium)
31
How Organisms Deal with Osmotic Pressure

• Paramecium (protist) removing excess water video

• Bacteria and plants have cell walls that prevent
  them from over-expanding. In plants the pressure
  exerted on the cell wall is called tugor
  pressure.
• A protist like paramecium has contractile
  vacuoles that collect water flowing in and pump
  it out to prevent them from over-expanding.
• Salt water fish pump salt out of their
  specialized gills so they do not dehydrate.
• Animal cells are bathed in blood. Kidneys keep
  the blood isotonic by remove excess salt and
  water.

32
Active Transport

• cell uses energy
• actively moves molecules to where they are needed
• Movement from an area of low concentration to an
  area of high concentration
• (Low ? High)
• Three Types

33
Types of Active Transport
Sodium Potassium Pumps (Active Transport using
proteins)

• 1. Protein Pumps -transport proteins that require
  energy to do work
• Example Sodium / Potassium Pumps are important
  in nerve responses.

Protein changes shape to move molecules this
requires energy!
34
Types of Active Transport

• 2. Endocytosis taking bulky material into a
  cell
• Uses energy
• Cell membrane in-folds around food particle
• cell eating
• forms food vacuole digests food
• This is how white blood cells eat bacteria!

35
Types of Active Transport

• 3. Exocytosis Forces material out of cell in
  bulk
• membrane surrounding the material fuses with cell
  membrane
• Cell changes shape requires energy
• EX Hormones or wastes released from cell

Endocytosis Exocytosis animations
36
What type of solution are these cells in?
C
B
A
Hypertonic
Isotonic
Hypotonic
37
THE KEYS THINGS ABOUT PASSIVE TRANSPORT ARE 1-
THEY DO NOT REQUIRE ENERGY and 2- THE THREE TYPES
ARE diffusion, osmosis, and facilitated
diffusion.
38
OSMOSIS
DIFFUSION OF WATER.

• What makes this type of diffusion have a special
  name?
• It is for WATER
• Diffusion is general, osmosis is specific
• Water must cross a membrane

In organisms, osmosis transports water INTO or
OUT OF cells.
CARROT EXAMPLE
39
PLANT CELLS!
WHAT TYPE OF CELLS HAVE CELLS WALLS? If there is
a lot of water entering a plants cells by
osmosis, it has a lot of water pressure pushing
out on the cell walls. This type of water
pressure is called
TURGOR PRESSURE
EXAMPLES OF HIGH AND LOW TURGOR PRESSURE Notice
the cell wall and the cell membrane.
40
The environment in which a cell resides The
solution in which the cell is exposed to (its
environment) will either make it shrink, swell,
or stay the same. There are 3 types of solutions
it can be in hypotonic, hypertonic, and isotonic.
Below beneath under Less than normal deficient
HYPO means

HYPER means
Over above beyond Excessive excessively
ISO means
Equal
41
LAB TIME
Lets explore some cells in different
environments.
42
HYPOTONIC
Solutions that have a LOWER amount of water
inside the cell than outside the cell.

.

• Water moves into cell from solution
• Cell expands (and may burst) CYTOLYSIS

43
MORE HYPOTONIC SOLUTIONS
CYTOLYSIS The swelling of a cell due to water
moving into the cell.
44
HYPERTONIC SOLUTIONS
Solutions that have a HIGHER amount of water
inside the cell than outside the cell.

• Water moves out of the cell into the solution
• Cell shrinks - plasmolysis

45
MORE HYPERTONIC SOLUTIONS
PLASMOLYSIS The water loss due to water moving
out of the cell to a lower concentration. Cell
will shrink.
46
ISOTONIC SOLUTION
Solutions that have an equal amount of water
inside the cell and outside the cell.
EQUILIBRIUM Equal amounts of water move in and
out of cell.
47
Facilitated Diffusion

• Only very very very small particles can get
  through a cell membrane by diffusion. A cell has
  another way of getting bigger ones inside.
  Facilitated diffusion allows larger particles to
  enter the membrane by diffusion. There are
  _____________ _______________ within the cell
  membrane that act as tunnels that let them in.
  When a particle gets inside the cell through
  these channels, it is called facilitated (helped)
  diffusion.

PROTEIN
CHANNELS
48
PASSIVE TRANSPORT IN ACTION Facilitated
diffusion for bigger particles
Molecules will randomly move through the opening
in a process called diffusion. This requires no
energy, molecules move from an area of high
concentration to an area of low
concentration. REQUIRES NO ENERGY
49
ACTIVE TRANSPORT
Processes where something gets into or out of the
cell by a procedure which uses ENERGY!
There are 3 types of active transport
PUMPS
ENDOCYTOSIS
EXOCYTOSIS
50
PUMPS
If a particle needs to get into or out of the
cell against the concentration gradient, it will
need to use ENEGY. This means that the particles
need to go from an area of LOW concentration to
an area of HIGH concentration. THEY ARE MOVING
AGAINST THE CONCENTRATION GRADIENT! Within the
cell membrane are PROTEINS that have channels
which act as pumps. Lets take a look at a
pump in action
51
PUMPS in action
Some proteins actively use energy from the ATPs
in the cell to drag molecules from area of low
concentration to areas of high concentration
(working directly against diffusion) an example
of this is the sodium/potassium pump. Here the
energy of a phosphate (shown in red) is used to
exchange sodium atoms for potassium atoms.
52
Large Particle Movement

• Sometimes larger things need to enter or exit the
  cell, but they cannot fit through a protein
  channel. They will enter or exit by endocytosis
  or exocytosis.

ENDOCYTOSIS Cell surround an object and engulfs
it within the membrane and forms a vacuole.
53
The cell membrane can also engulf structures that
are much too large to fit through the pores in
the membrane proteins this process is known as
endocytosis. In this process the membrane itself
wraps around the particle and pinches off a
vesicle inside the cell. In this animation an
ameba engulfs a food particle.
54
EXOCYTOSIS

• The cell pushes a vacuole to its surface, the
  vacuole opens and the object is expelled.

Large molecules that are manufactured in the cell
are released through the cell membrane.
55
EXAMPLES of ENDO
White blood cells Amoeba engulfing paramecium
EXAMPLES of EXO
Cells expelling waste

• Exocytosis (animation) click for movie link

56
THE END
Part of this powerpoint taken from
www.worldofteaching.com