Chapter 4: Cells in Action
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Cells in Action
A cell is a factory: an organism must obtain energy, raw materials, and eliminate waste.
These functions keep cells healthy so they can grow through cell division.
Cell growth allows cells to divide, therefore growing and repairing tissue as needed.
Diffusion
Particles naturally travel from crowded areas (dense) to less dense places.
Diffusion is the process by which molecules spread from areas of high concentration, to
areas of low concentration.
When the particles are even throughout a space - it is
called EQUILIBRIUM
Diffusion
Molecules move from areas of High concentration to areas of Low concentration.
Osmosis
Cells are surrounded by and filled with mostly water.
Diffusion of water is so important that it was given a special name – Osmosis.
Pure water has the highest concentration of water molecules
Osmosis – Diffusion
Chapter 4: Cells in Action
Red Blood Cells
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Pure Water would rush into a Red Blood Cell
Plasma – would maintain the Red Blood Cells
Isotonic:
Cells maintain normal shape.
Hypertonic Solution:
Cells shrink because water departs the cell
Hypotonic Solution:
Cells swell as they take in more water and rupture.
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Chapter 4: Cells in Action
 Passive Transport – Small Particles:
 Particles move through channels (protein cells). Diffusion and Osmosis are examples of
Passive Transport - Thus no Energy is used for particles to move (High- Low) through a
membrane.
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 Active Transport - Energy:
 Active Transport usually involves the movement of small particles from an area of low
concentration to an area of High concentration.
 Thus using Energy to perform this process.
 Large Particles:
Large Particles use Active Transport to move in and out of cells
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to move in and out of
cells
 Reverse Osmosis is a process that forces water across semipermeable membranes under
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Chapter 4: Cells in Action
 Reverse Osmosis:
 Reverse Osmosis is a process that forces water across semipermeable membranes under
high pressure. The high pressure reverses the natural tendency of the solutes to travel
from high to low concentration areas – this is how water is purified.
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Endocytosis
Cell comes in contact with particle
Cell membrane begin to wrap around particle
The particle is completely surrounded – vesicles pinch off.
Endocytosis means “within the cell”
Chapter 4: Cells in Action
Endocytosis
Three Types: Phagocytosis, Receptor-Mediated and Pinocytosis.
Phagocytosis – captures large particles by sending out pseudopods (false feet)
Receptor Mediated – receptors on the membrane captures specific substances before
endocytotic process begins.
Pinocytosis– the cell membrane usually surrounds a substance – forming a vesicle to carry it into
the cell.
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Exocytosis
Large particles are packaged in vesicles to leave the cell
Vesicle travels to membrane wall and fuses.
Cell releases the Vesicle
Exocytosis means “Outside the Cell”
Materials discharged from cell (vacuole passes plasma membrane to dump contents out of
cell).
Photosynthesis:
Plants use the energy captured by chlorophyll to change carbon dioxide and water into food.
Glucose is a carbohydrate used by plants to convert sunlight into stored sugars (Energy).
Chapter 4: Cells in Action
Cellular Respiration:
 Cellular Respiration uses oxygen to breakdown food.
Photosynthesis vs Cellular Respiration:
Photosynthesis:
Uses Sunlight Energy and CO to make Glucose and releasing O
2
Cellular Respiration:
Cells use O to breakdown glucose and Releases CO .
2
2
2
Chapter 4: Cells in Action
 Cells in Action:
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 A cell is a _____________: an organism must obtain ____________,
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 raw ______________, and eliminate _____________.
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 These functions keep cells healthy so they can grow through cell
division.
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 Cell growth allows cells to ______________, therefore
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 _________________ and repairing _______________ as needed.
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 Diffusion:
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Particles naturally travel from crowded areas (dense) to less dense
places.
Diffusion is the process by which molecules spread from areas of
___________ concentration, to areas of ________ concentration.
When the particles are even throughout a space - it is
called ____________________.
Chapter 4: Cells in Action
Diffusion
Molecules move from areas of _________ ____________________
to areas of ________________ ________________________.
Osmosis
Cells are ______________________ by and ________________ with
mostly water.
___________________ of water is so important that it was given a
special name – Osmosis.
Pure water has the highest concentration of water molecules
Osmosis – Diffusion
Chapter 4: Cells in Action
Red Blood Cells
Pure Water would ________ into a Red Blood Cell
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Plasma – would maintain the Red Blood Cells
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Isotonic:_______________________________________________
______________________________________________________
Cells maintain normal shape.
Hypertonic Solution: ____________________________________
Cells shrink because water departs the cell
Hypotonic Solution: _____________________________________
______________________________________________________
Cells swell as they take in more water and rupture.
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Chapter 4: Cells in Action
 Passive Transport – Small Particles:
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 Particles move through channels (_______________ cells).
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Diffusion and _________________ are examples of Passive
Transport - Thus no ________________ is used for particles to move
(_________- ________) through a membrane.
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 Active Transport - Energy:
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 Active Transport usually involves the movement of small particles
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 from an area of _______ concentration to an area of _______
concentration.
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 Thus using Energy to perform this process.
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 Large Particles:
Large Particles use Active Transport to move in and out of cells
Chapter 4: Cells in Action
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to move in and
out of cells
 Reverse Osmosis:
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 Reverse Osmosis is a process that forces water across
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 ______________________ membranes under _______ pressure.

 The high pressure reverses the natural tendency of the solutes to

 travel from high to low concentration areas – this is how water is
purified.

Chapter 4: Cells in Action
Endocytosis
Cell comes in contact with particle
Cell membrane begin to __________ around particle
The particle is completely surrounded – vesicles _____________ off.
Endocytosis means “_____________ ______ _________”
Endocytosis
____________Types: Phagocytosis, Receptor-Mediated and
Pinocytosis.
Phagocytosis – captures large particles by sending out pseudopods
(________ _________)
Receptor Mediated – receptors on the membrane captures
_________________ substances before endocytotic process begins.
Pinocytosis– the cell membrane usually surrounds a substance –
forming a _______________ to carry it into the cell.
Chapter 4: Cells in Action
Exocytosis
__________ particles are packaged in vesicles to leave the cell
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 ____________ travels to membrane wall and fuses.
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 Cell releases the Vesicle
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 Exocytosis means “________________ _______ __________”
Materials discharged from cell (vacuole passes ______________
_______________________ to dump contents out of cell).
Photosynthesis:
Plants use the energy captured by ______________________ to change
____________ _____________ and water into food.
Glucose is a ______________________ used by plants to convert
sunlight into stored sugars (Energy).
Chapter 4: Cells in Action
Cellular Respiration:
 Cellular Respiration uses oxygen to breakdown food.
Photosynthesis vs Cellular Respiration:
Photosynthesis:
Uses Sunlight Energy and CO to make Glucose and releasing O
2
Cellular Respiration:
Cells use O to breakdown glucose and Releases CO .
2
2
2
Chapter 4: Cells in Action