Name_____________________________________
Period________
Date_____________
Objective: SWBAT describe active transport.
Do Now
Vocabulary
Activity #1
Activity #2
Exit
DO NOW
True or False
Plant and animal cells both have a nucleus
True
False
Only plant cells have cell walls
True
False
Cells get all their minerals by diffusion
True
False
Root cells and hair cells contain lots of chloroplasts.
True
False
Chlorophyll contain chloroplasts
True
False
VOCABULARY (Use your text to define the words below.)
Active
transport
Inhibitors
Against a
concentration
gradient
Endocytosis
Phagocytosis
Pinocytosis
ACTIVITY #1-Reading (Annotate the text as you read.)
Active Transport - Energy to Transport
Active transport describes what happens when a cell uses energy to transport something. We're not talking about
phagocytosis (cell eating) or pinocytosis (cell drinking) in this section. We're talking about the movement of
individual molecules across the cell membrane. The liquids inside and outside of cells have different substances.
Sometimes a cell has to work and use some energy to maintain a proper balance of ions and molecules.
Active transport usually happens across the cell membrane. There are thousands of proteins embedded in the cell's
lipid bilayer. Those proteins do much of the work in active transport. They are positioned to cross the membrane so
one part is on the inside of the cell and one part is on the outside. Only when they cross the bilayer are they able to
move molecules and ions in and out of the cell. The membrane proteins are very specific. One protein that moves
glucose will not move calcium (Ca) ions. There are hundreds of types of these membrane proteins in the many cells
of your body.
Many times, proteins have to work against a concentration gradient. That term means they are pumping something
(usually ions) from areas of lower to higher concentration. This happens a lot in neurons. The membrane proteins
are constantly pumping ions in and out to get the membrane of the neuron ready to transmit electrical impulses.
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Even though these proteins are working to keep the cell alive, their activity can be stopped. There are poisons that
stop the membrane proteins from transporting their molecules. Those poisons are called inhibitors. Sometimes the
proteins are destroyed and other times they are just plugged up.
Imagine that you are a cell and have ten proteins working to pump calcium into the cell. What if a poison came
along and blocked eight of them? You could not survive with just two pumps working and would slowly die. It would
be like expecting you to breathe with your mouth and nose plugged up.
1. Describe the two major types of active transport?
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2. What are the similarities and differences between diffusion and active transport by protein pump?
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3. Energy for active transport comes from a cell’s ___________________.
A. Golgi complex
B. nucleus
C. mitochondria
D. lysosomes
4. What does working against a gradient mean? (Use this sentence starter. Working against the gradient means…)
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5. Where does active transport occur?
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Activity #2 Endocytosis
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Endocytosis is a type of active transport that moves particles, such as large molecules, parts of cells, and even whole
cells, into a cell. There are different endocytosis variations, but all share a common characteristic: the cell's plasma
membrane fold inward, forming a pocket around the target particle. The pocket pinches off, resulting in the particle
containing itself in a newly created intracellular vesicle formed from the plasma membrane.
Phagocytosis (the condition of “cell eating”) is the process by which a cell takes in large particles, such as other cells
or relatively large particles. For example, when microorganisms invade the human body, a type of white blood cell, a
neutrophil, will remove the invaders through this process, surrounding and engulfing the microorganism, which the
neutrophil then destroys.
In preparation for phagocytosis, a portion of the plasma membrane's inward-facing surface becomes coated with
the protein clathrin, which stabilizes this membrane's section. The membrane's coated portion then extends from
the cell's body and surrounds the particle, eventually enclosing it. Once the vesicle containing the particle is
enclosed within the cell, the clathrin disengages from the membrane and the vesicle merges with a lysosome for
breaking down the material in the newly formed compartment (endosome). When accessible nutrients from the
vesicular contents' degradation have been extracted, the newly formed endosome merges with the plasma
membrane and releases its contents into the extracellular fluid. The endosomal membrane again becomes part of
the plasma membrane.
A variation of endocytosis is pinocytosis. This literally means “cell drinking”. Discovered by Warren Lewis in 1929,
this American embryologist and cell biologist described a process whereby he assumed that the cell was
purposefully taking in extracellular fluid. In reality, this is a process that takes in molecules, including water, which
the cell needs from the extracellular fluid. Pinocytosis results in a much smaller vesicle than does phagocytosis, and
the vesicle does not need to merge with a lysosome
In receptor-mediated endocytosis, as in phagocytosis, clathrin attaches to the plasma membrane's cytoplasmic side.
If a compound's uptake is dependent on receptor-mediated endocytosis and the process is ineffective, the material
will not be removed from the tissue fluids or blood. Instead, it will stay in those fluids and increase in concentration.
The failure of receptor-mediated endocytosis causes some human diseases. For example, receptor mediated
endocytosis removes low density lipoprotein or LDL (or "bad" cholesterol) from the blood. In the human genetic
disease familial hypercholesterolemia, the LDL receptors are defective or missing entirely. People with this condition
have life-threatening levels of cholesterol in their blood, because their cells cannot clear LDL particles.
Although receptor-mediated endocytosis is designed to bring specific substances that are normally in the
extracellular fluid into the cell, other substances may gain entry into the cell at the same site. Flu viruses, diphtheria,
and cholera toxin all have sites that cross-react with normal receptor-binding sites and gain entry into cells.
The reverse process of moving material into a cell is the process of exocytosis. Exocytosis is the opposite of the
processes we discussed above in that its purpose is to expel material from the cell into the extracellular fluid. Waste
material is enveloped in a membrane and fuses with the plasma membrane's interior. This fusion opens the
membranous envelope on the cell's exterior, and the waste material expels into the extracellular space. Other
examples of cells releasing molecules via exocytosis include extracellular matrix protein secretion and
neurotransmitter secretion into the synaptic cleft by synaptic vesicles.
TYPES OF ENDOCYTOSIS
Phagocytosis
Pinocytosis
Receptor-meditated
endocytosis
Describe the
process/purpose
Nickname
What causes the human genetic disease familial hypercholesterolemia?
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REGENTS QUESTIONS
1. Which means of particle transport requires input of energy from the cell?
a. diffusion
b. osmosis
c. facilitated diffusion
d. active transport
Figure 7-5
2. Which means of particle transport is shown in Figure 7–5 above?
a. endocytosis
b. exocytosis
c. facilitated diffusion
d. protein pump
3. What is true about active transport?
a. it requires energy
c. It moves substances down the concentration gradient
b. it does not require energy
d. it moves material from high to low concentration
4. Engulfing of bacteria by white blood cells is called as
a. Phagocytosis
b. Pinocytosis
c. Exocytosis
d. Endocytosis
5. A substance is most likely to diffuse into a cell when
a. it is a large organic food molecule such as protein or starch
b. it is enclosed in an organelle such as a vacuole
c. the concentration of the substance is greater outside the cell than inside
d. the pH of the substance is greater than the pH of the cell
EXIT TICKET
After the lesson, now I understand…
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Something I still need help with…
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Glucose enters cells most rapidly by _________________
A. diffusion
B. facilitated diffusion
C. ion channels
D. phagocytosis
________________ transport requires energy from ATP to move substances across membranes.
A. Passive
B. Active
A cell must expend energy to transport substances using ________________.
A. diffusion
B. facilitated diffusion
C. ion channels
D. osmosis
E. endocytosis
White blood cells engulf, digest, and destroy invading bacteria using __________________.
A. Facilitated diffusion
B. pinocytosis
C. phagocytosis
D. osmosis
The carrier proteins that help in facilitated diffusion are _______________ proteins.
A. peripheral
B. integral
All of the
A.
B.
C.
D.
E.
following are kinds of passive transport EXCEPT ________________________
diffusion
facilitated diffusion
osmosis
phagocytosis
ion channels
Endocytosis that brings in small dissolved molecules (solutes) and fluids is called ___________________.
A. pinocytosis
B. phagocytosis
C. facilitated diffusion
D. osmosis
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Golgi bodies use ____________________ to transport molecules out of cells.
A. ion channels
B. phagocytosis
C. pinocytosis
D. exocytosis
The pressure exerted by water moving during osmosis is called __________________ pressure.
A. tonic
B. diffusion
C. selectively permeable
D. osmotic
Placing an animal cell in a hypotonic solution will cause water to ______________________.
A. move into the cell
B. move out of the cell
When molecules move DOWN the concentration gradient it means they are moving from ______________
A. an area of low concentration to an area of higher concentration
B. an area of high concentration to an area of lower concentration
Gases like oxygen and carbon dioxide move across cell membranes using _____________________
A. endocytosis
B. ion channels
C. diffusion
D. facilitated diffusion
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Complete the transport terms.
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*
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1. Active transport requires _E_ __ __ __ __ __ to move molecules across membranes.
2. _A_ __ __ is the molecule that provides the energy for active transport.
3. Golgi bodies use _E_ __ __ __ __ __ __ __ __ __ to release molecules outside the
cell.
4. _D_ __ __ __ __ __ __ __ __moves oxygen and carbon dioxide molecules from a high concentration to
a low
concentration across membranes.
5. The cell organelles that burns glucose and provides ATP for active transport are the
_M_ __ __ __ __ __ __ __ __ __ __ __,
6. Water moves across membranes by _O_ __ __ __ __ __ __.
7. A small membrane sac used to transport substances during exocytosis & endocytosis
= _V_ __ __ __ __ __ __
8. Kind of endocytosis that takes in small dissolved molecules (solutes) or fluids
= _P_ __ __ __ __ __ __ __ __ __ __
9. _P_ __ __ __ __ __ __ transport does NOT REQUIRE energy.
10. During _F_ __ __ __ __ __ __ __ __ __ __ diffusion carrier proteins grab glucose molecules, change
shape, and flip to the other side of the membrane, like a revolving door.
11. A _C_ __ __ __ __ __ __ protein is an integral membrane protein that helps move molecules across a
cell
membrane.
12. A cell placed in an _I_ __ __ __ __ __ __ __ solution neither swells or shrinks because the
concentration
of molecules outside the cell is the same as inside.
13. A solution in which there is a HIGHER concentration of molecules OUTSIDE the cell than inside
= _H_ __ __ __ __ __ __ __ __ __.
14. A CONCENTRATION _G_ __ __ __ __ __ __ __ forms whenever there is a difference in
concentration
between one place and another.
15.Pinocytosis, phagocytosis, and Na+-K+ pumps are all kinds of _A_ __ __ __ __ __ transport because
they
use energy to move substances across membranes.
16. A solution in which the concentration of molecules outside the cell is LOWER than inside
= _H_ __ __ __ __ __ __ __ __.
17. A _S_ __ __ __ __ __-_P_ __ __ __ __ __ __ __ __ _P_ __ __ __ uses ATP to move three
Na+ ions out of a cell while it moves two K+ ions in.
18. Pinocytosis & phagocytosis are both kinds of _E_ __ __ __ __ __ __ __ __ __ __.
19. When molecules move from high to low along a concentration gradient we say they are moving
“_D_ __ __ __” the gradient.
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20. _O_ __ __ __ __ __ __ pressure is caused by water inside a plant cell pushing against the cell wall.
21. The shrinking of a plant cell membrane away from the cell wall when placed in a hypertonic solution is
_P_ __ __ __ __ __ __ __ __ __ __.
22. White blood cells use _P_ __ __ __ __ __ __ __ __ __ __ __ to engulf and destroy bacteria that
glycoproteins recognize as “not self”.
23. The swelling and bursting of animal cells when placed in a hypotonic solution is called
_C_ __ __ __ __ __ __ __ __.
24. Proteins (like carrier proteins) that stick INTO the cell membrane either part way or all the way
through are called _I_ __ __ __ __ __ __ __ proteins.
25. Ca++, H+, Na+, and K+ move across membranes by going through passageways called
_I_ __ __ _C_ __ __ __ __ __ __ __.
called
the
LOOK AT THE DIAGRAMS. The black dots
represent solute molecules dissolved in water
In which beaker is the concentration of solute
the greater?
A
*
*
A
or
B
*
*
*
B
*
*
*
*
*
*
*
*
*
*
If the solute (dots) in this diagram is unable to pass through the dividing
membrane, what will happen?
A. the water level will rise on the right side of the tube
B. the water level will rise on the left side of the tube
C. the water level will stay equal on the two sides
*
*
*
*
*
COMPARE/CONTRAST
the kinds of transport
*
*
Active (ATP)
or
Passive
(KINETIC
ENERGY)
*
*
*
*
What does it use to
help:
Membrane proteins?
Vesicles?
Needs no help
(phospholipids)?
*
*
*
*
Example of
substance(s) that
use this kind of
transport in cells
DIFFUSION
FACILITATED
DIFFUSION
OSMOSIS
FACILITATED
DIFFUSION
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(ION CHANNELS)
SODIUM-POTASSIUM
(NA+ -K+) PUMP
(ANIMALS)
ENDOCYTOSIS
(PHAGOCYTOSIS)
ENDOCYTOSIS
(PINOCYTOSIS)
EXOCYTOSIS
RECEPTOR-MEDIATED
ENDOCYTOSIS
PROTON PUMP
(PLANTS)
Modified from: http://brookings.k12.sd.us/biology/other_units.htm
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