Transcript Chapter 7.5 PowerPoint

Chapter 4
Section 2 Active Transport
Objectives
• Compare active transport with passive transport.
• Describe the importance of the sodium-potassium
pump.
• Distinguish between endocytosis and exocytosis.
• Identify three ways that receptor proteins can
change the activity of a cell.
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• Many important cellular substances have a lower
concentration outside the cell than inside the cell
• If a cell could only move substances with passive
transport, where would these substances move?
out of the cell
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Chapter 4
Section 2 Active Transport
Movement Against a Concentration Gradient
• To move certain substances into the cell, they must
have a way to move substances _________
against the
concentration gradient…
low
high
– That is from a __________
to ___________
concentration
energy
– This type of transport requires ____________
so it
is called _____________
transport
active
– It is similar to how you need energy to swim
against the flow of a river
___________
• Most often, the energy needed for active transport is
supplied directly or indirectly by _________.
ATP
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carrier
• Some active transport processes use __________
proteins, like those used in facilitated diffusion
• So let’s review…
– A carrier protein…
binds
• _________
to a substance
carries it across the membrane
• _________
releases it on the other side
• _________
• However, in active transport, carrier proteins move
low
high
substances from a ________
to _________
“pump”
concentration, acting like a membrane __________
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Chapter 4
Section 2 Active Transport
• One of the most important membrane pumps in
animal cells is a carrier protein called the
potassium pump.
___________
sodium - __________
• In a complete cycle, the sodium-potassium pump
out of
transports __________
sodium ions, Na+, ______
three
into the cell.
a cell and two potassium ions, K+, _____
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Chapter 4
Section 2 Active Transport
Sodium-Potassium Pump
• Na+ =
• K+ =
outside
inside
• If this was passive transport, which way would the
sodium ions move?
in
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Chapter 4
Section 2 Active Transport
Sodium-Potassium Pump
• Na+ =
• K+ =
outside
inside
• If this was passive transport, which way would the
potassium ions move?
out
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Chapter 4
Section 2 Active Transport
Sodium-Potassium Pump
• Na+ =
• K+ =
• But active transport, makes the ions move in the
opposite
_________________
direction
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Chapter 4
Section 2 Active Transport
• Step 1: _________
Three sodium ions and a __________
phosphate
group from ATP bind to the pump
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Chapter 4
Section 2 Active Transport
• Step 2: The pump changes ________
shape and transports
out
sodium ions ________
of the cell
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Chapter 4
Section 2 Active Transport
• Step 3: Two ______________
ions bind to the pump
potassium
into
and are transported _________
the cell
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Chapter 4
Section 2 Active Transport
• Step 4: The phosphate group is ____________
released back
inside the cell
•
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•
The sodium-potassium pump is important for animal
bursting
cells because it prevents them from ____________
– Sodium ions naturally diffuse into the cell through
ion channels
– if they couldn’t get out, which way would
water move to balance out the particles?
inside
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• Some simpler organisms have a different “pump”
contractile
called a ______________
vacuole
push water out of
• It expands and contracts to _________
the cell
• This is important because it lives in a watery
hypotonic
environment, which would be a _____________
solution
paramecium
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Chapter 4
Section 2 Active Transport
Movement in Vesicles
proteins and
• Many substances, such as _____________
large to be transported
____________________,
polysaccharides are too __________
by carrier proteins.
• These substances are moved across the cell membrane by
vesicles
_______________.
• The movement of a substance into a cell by a vesicle is called
endocytosis
__________________
– Think “en” is like “in”
• The movement of a substance by a vesicle to the outside of a
exocytosis
cell is called ___________________.
– Think “ex” is like exit
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Chapter 4
Section 2 Active Transport
Endocytosis
pouch around a
• The cell membrane forms a _________
substance, then ________
pinches off to form a vesicle that
food
transports materials, like ________,
into the cell
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• There are two types of endocytosis
solid
– Phagocytosis = engulfing __________
particles
like food
• http://highered.mcgrawhill.com/sites/0072495855/student_view0/chapt
liquid
er2/animation__phagocytosis.html
– Pinocytosis = engulfing ____________ particles
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Chapter 4
Section 2 Active Transport
Exocytosis
fuses to the cell membrane, which
• The vesicle _________
__________
up to release items like _______
opens
waste or
proteins
____________
made by the cell
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Chapter 4
Section 2 Active Transport
Membrane Receptor Proteins
communicate with each other to
• Cells must ______________
coordinate your growth, metabolism, and other
activities
signal
• To do so, some cells release ____________
molecules that carry information or
______________
________________
to nearby cells
messages
• Cells can receive the messages because the cell
membrane contains specialized proteins, called
receptor
______________
proteins, that bind to these signal
molecules.
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Chapter 4
Section 2 Active Transport
• When signal molecules bind to receptor proteins,
they may cause three different changes in the
cell…
permeability
– Changes in ________________________
second
– Triggering the formation of a __________
messenger
______________
enzymes
– Activating ________________
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Chapter 4
Section 2 Active Transport
Changes in Permeability
• The binding of a signal molecule to the receptor protein causes
open allowing specific ions to cross
an ion channel to __________,
the cell membrane.
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Chapter 4
Section 2 Active Transport
Second Messengers
signal
• The original _____________
molecule triggers the production of
a second messenger, which may trigger a series of
biochemical
_______________________
reactions in the cell
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Chapter 4
Section 2 Active Transport
Enzyme Action
• When a signal molecule binds to the receptor protein, the receptor
enzyme speeding up chemical
protein may act as an ____________,
reactions inside the cell.
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drugs
• Many __________
affect the binding of signal
molecules to receptor proteins, affecting the function
of the cell
– Examples…
imitates
• The illegal drug heroin _____________
a
signal molecule and binds to receptor proteins
beta
• Prescribed drugs called ________
blockers
_____________
prevent or block signal
molecules from binding to receptor proteins in
heart
___________
cells, which _________
slows down
the heart rate of patients with rapid heart beats
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Question 1
•
Which molecule provides energy for active transport
to occur?
A. chlorophyll
B. ATP
C. Carbon dioxide
D. Signal molecule
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Question 2
•
In the sodium potassium pump, which substances
get released inside of the cell?
A. Sodium ions
B. Potassium ions
C. Phosphate groups
D. Both B and C
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Question 3
•
Which substance would a cell take in through
endocytosis?
A. Sodium ions
B. polysaccharides
C. Amino acids
D. monosaccharides
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Question 4
•
What type of membrane protein interacts with signal
molecules?
A. Cell surface marker
B. Receptor protein
C. Transport protein
D. enzymes
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Question 5
Which type of transport may occur in dead
cells…passive or active?
passive
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