Transcript 2-1 Exchange with the Environment Version b

Chapter 2
The Cell in Action
2-1
Exchange With the
Environment
Essential Questions
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Explain the process of diffusion.
Describe how osmosis occurs.
Compare active transport with passive
transport.
Explain how large particles get into and out
of a cell.
Science Terms
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Diffusion
Osmosis
Passive transport
Active transport
Endocytosis
Exocytosis
Exchange with the Environment:
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What would happen if your mom and dad did not bring
home any more food and you couldn’t use the toilets or
bring out the garbage?
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You would run out of food and you would have way too much
garbage around.
What is Diffusion?
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Diffusion is the movement of particles from
an area of higher concentration to an area of
lower concentration.
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What does this mean?
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This means that particles will move from where there are
a lot of them and spread out as far as they can from
each other.
Does Diffusion use energy?
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NO!
Diffusion of Water:
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What are cells mostly made of?
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Water!!!
Whenever you mix water with something else,
Lower
you _______________
the concentration of
water.
Diffusion of Water:
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The cell membrane has small holes called
pores, and this makes the membrane…
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Semi-permeable.
What does it mean to be semi-permeable?
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This means that SOME materials are let through
the membrane while others are not!
Osmosis
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What is it?
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The diffusion (movement) of water across the cell
membrane.
Does osmosis use energy?
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NO!
Cells and Osmosis
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What is plasma mostly made of?
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Water!
Cells and Osmosis
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Why would a red blood cell burst if you put
them into pure water?
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The concentration of water outside the cell is
higher than the concentration of water inside the
cell. This means that…
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Water moves into the cell until it…
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Bursts!
Cells and Osmosis:
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Why do plants wilt if they don’t have enough
water?
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The vacuoles empty and cannot support the cell
wall. This causes the plant to wilt!
Add water and the vacuoles refill and cause
the plant to become firm again.
Moving Small Particles
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How are small particles such as sugars
passed across the cell membrane?
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Protein channels
Passive Transport
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What is it?
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Passive transport is moving substances across
the…
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Cell membrane without the use of…
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ENERGY
Passive Transport
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Two examples of Passive Transport are…
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Diffusion
Osmosis
Does Passive Transport use energy?
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NO!!!
Active Transport
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What is it?
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The movement of particles across the cell
membrane WITH the use of ENERGY!!!
Usually from areas of lower concentration to
areas of higher concentration.
Does it use energy?
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YES!
Active Transport
Moving Large Particles:
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What are the two types of movement of very
large particles across the cell membrane?
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Endocytosis
Exocytosis
Endocytosis
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What is it?
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What are the particles put inside of?
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The process of bringing very large particles INTO
the cell.
A vesicle!
Does endocytosis use energy?
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YES!
Exocytosis:
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What is it?
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What are the particles put inside of?
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The process of moving large particles out of a cell
A vesicle (now a lysosome)
Does exocytosis use energy?
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YES!