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Cell Structure and Function - Review
View cell structure function
cytoplasm
cytoskeleton
ribosomes
Cell “plasma”
Membrane
Nucleus
Endoplasmic
reticulum
Mitochondrion
Lysosome
Golgi Body
Cell Boundaries
The cell membrane regulates what enters and leaves the cell and also
provides protection and support. The composition of nearly all cell membranes
is a double-layered sheet called a lipid bilayer. As you can see in Figure 7-12,
there are two layers of lipids, hence the name bilayer. The lipid bilayer gives
cell membranes a flexible structure that forms a strong barrier between the
cell and its surroundings. The Plasma Membrane
Identification makers
Figure 7-12
Biology – Homeostasis
Topics
Essential Questions
• Investigate and
analyze the cell as
a living system
including:
1. How is homeostasis maintained?
How are temperature, pH, blood
glucose and water balanced?
• Maintenance of
homeostasis.
2. What is the difference between
active and passive transport?
What is a semi permeable
membrane?
• Movement of
materials into and
out of cells.
3. What is osmotic pressure; can
you predict changes? (isotonic,
hypotonic, and hypertonic)
Homeostasis
Homeostasis is the property of a system that regulates its
internal environment and tends to maintain a stable,
constant condition of properties like temperature, water
balance or pH.
Homeostasis Overview
Cellular Homeostasis
The Cell Membrane
Overview of the cell “plasma” membrane structure
Protein with
marker
Receptor protein
Channel protein
Phospholipid
bilayer
Active
transport
protein
cholesterol
Why are the
tails moving
away?
Passive Transport
Diffusion describes the spread of
particles through random motion
from regions of higher
concentration to regions of lower
concentration. Diffusion
Osmosis is the movement of
water molecules through a
selectively permeable membrane
into a region of higher solute
concentration, aiming to equalize
the solute concentrations on the
two sides
Active and Passive Transport
Passive Transport
Osmosis
Virtual Lab diffusion
Tonicity is a measure of the osmotic pressure gradient (as defined by the
water potential of the two solutions) of two solutions separated by a
semipermeable membrane. It is commonly used when describing the
response of cells immersed in an external solution.
Osmosis Demo
Hypotonic Solution If water molecules continue to diffuse into the cell, it
will cause the cell to swell, up to the point that cytolysis (rupture) may
occur
Isotonic solution isotonic environment happens when an equal
concentration exists inside and outside the cell
Hypertonic Solution If water molecules continue to diffuse out of the cell,
it will cause the cell to shrink, or crenate.
Animal cell
Plant cell
Active Transport
is the movement of a substance against its concentration
gradient (from low to high concentration) requiring the use of
Energy.
Endocytosis and
Exocytosis