The Cell in Action!!!
STATE UNIVERSITY OF SURABAYA
By: Ms. Dhita
Section 1 Objectives:
•Explain the process of diffusion
•Describe how osmosis occurs
•Compare passive transport with active
•Explain how large particles get into
and out of cells
Exchange with the Environment
An organism must be able to obtain energy and
raw materials and get rid of waste.
Cell division allows organisms to grow and repair
Exchange of materials between a cell and its
environment takes place at the cell’s membrane.
What is Diffusion?
Everything is made up of moving particles.
Particles travel from where they are crowded to
where they are less crowded.
This movement from areas of high concentration
(crowded) to areas of low concentration (less
crowded) is called DIFFUSION
Cells do not need energy to use energy for diffusion
Diffusion of Water
Cells of organisms are surrounded by and filled with
fluids that are made mostly of water.
OSMOSIS – the diffusion of water through cell
Water is made of up molecules
Pure water has the highest concentration of water
molecules, but when you mix something, you lower the
concentration of water molecules.
Semipermeable means only certain substances can
If certain substances pass through a semipermeable
membrane, over time the water molecules move
from the liquid with the high concentration of water
to the liquid with low concentration of water
The Cell and Osmosis
The Animal Cell The Plant Cell
Plasma (surrounds red Osmosis occurs in plant
blood cells) is made up of cells
water, salts, and sugars. When a wilted plant is
Concentration of these watered, osmosis makes
particles is kept in the plant firm again!
balance by osmosis.
Hypotonic, Isotonic, & Hypertonic Solution
If environment is:
MORE SOLUTES outside cell
MORE WATER IN CELL
over time, cell loses water
“Iso-” means environment “=” cell
No change in cell volume
LESS SOLUTES outside cell
LESS WATER IN CELL, more solutes in cell.
over time, cell gains water
Comparison of 3 Types of Solutions
HYPERTONIC ISOTONIC HYPOTONIC
Moving Small Particles
Small particles, such as sugars, cross the cell membrane
through passageways called CHANNELS.
Channels are made up of proteins in the cell membrane.
Particles travel through the channels either through:
Passive Transport Active Transport
Movement of particles across Process of transporting
a cell membrane without the
particles that requires
use of energy by the cell.
the cell to use energy.
Particles move from an area
Usually involves the
of high concentration to an
area of low concentration. movement of particles
Diffusion and Osmosis are from an area of low
examples of Passive concentration to an area
of high concentration!
Moving Large Particles
Large particles move into and out of the cell by
Endocytosis = “Within the Cell”
Exocytosis = “Outside the Cell”
Active transport process that surrounds a large particle.
Encloses the particle in a vesicle.
Brings the particle into the cell.
2 types of endocytosis:
What are Vesicles??
Sacs formed from pieces of cell membrane
Active transport which moves large particles out of
A vesicle forms around a large particle within the
Vesicle carries the particle to the cell membrane.
Vesicle fuses with the cell membrane and releases
the particle to the outside of the cell.
Quiz . . .
What is the difference between active
transport and passive transport!
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