Specialized cells have unique structures and functions: - Fat cells store fat and expand greatly in size, with little cytoplasm but large amounts of fat. Cone cells in the eye contain visual pigments and many mitochondria to power changes in pigment allowing color vision. Root hair cells have a large vacuole to increase water absorption through osmosis. Sperm cells have a tail for propulsion, mitochondria for energy, and an acrosome of enzymes to penetrate eggs. Nerve cells transmit electrical signals along axons to distant areas, aided by insulating myelin sheaths.

1. SPECIALISED
CELLS
Some examples

2. FAT CELL
• If you eat more fat than you need, your body
makes fat & stores is in fat cells.
• These cells help animals to survive when food is in
short supply.
• !

3. • They have a small amount of cytoplasm and large amounts of
fat. Why do you think they have only a small amount of
cytoplasm?
• They have few mitochondria. Why?
• They can expand – a fat cell can end up 1000 times its original
size as it fills up with fat!

4. CONE CELL
• Found in light-sensitive layer of our eye (retina)
• Enable us to see in color
• The outer segment contains a chemical, the visual pigment,
which changes in colored light.
• Energy is needed to change the visual pigment back to its
original form

5. • The middle segment is packed full of mitochondria.
Why do you think this is?
• The final part of the cone cell is a specialized synapse
that connects to the optic nerve When colored light
makes the visual pigment change, an impulse is
triggered. The impulse crosses the synapse and
travels along the optic nerve. What happens to this
impulse?

6. ROOT HAIR
CELL
• Found close to the tip of growing roots.
• Plants need water and dissolved mineral ions. What
do they need these for?
• Root hairs increase the surface area. Why is a large
surface area beneficial?
• Root hair cells have a large permanent vacuole that
speeds up the movement of water from the soil into
the cell by osmosis.

7. SPERM CELL
• Sperm cells must travel a long way to fertilize an egg!
Depending on the animal, it may need to travel
through water or through the female reproductive
system.
• They carry paternal genetic information.
• They must break into the egg when they eventually
get there.

8. • Sperm cells have a long tail which whips from side-to-side.
What is the function of this tail?
• The middle section is full of mitochondria. Why does it need
so many mitochondria?
• The acrosome stores digestive enzymes for breaking down
the outer layers of the egg. Why is the location of the
acrosome important?
• A large nucleus contains the genetic information.

9. NERVE CELL
• Neurons make up nerves and carry impulses between sensory
organs and effectors, and the brain.
• Dendrites are extensions of the cell and receive information
which they pass on. They provide a large surface area. Why is
this beneficial?
• The axon is a long extension of the cell body and carries
impulses to the axon terminal. Where does the impulse go next?
Why does the axon need to be long?

10. • The myelin sheath insulates the axon to prevent
loss of the impulse and makes it travel quickly. Why
is this important?
• The impulse finally arrives in the synaptic end
button where neurotransmitters are stored. What
happens to these neurotransmitter chemicals at
the synapse?