Specialisation in cells

Main idea:

All cells are specialised in order to carry out their functions effectively.

Terms:

Surface area to volume ratio –> not surface area!

Red Blood Cells

Description

Red
Biconcave disc (both sides are concave)
Round
No nucleus
Contains haemoglobin (the oxygen-carrying protein)
Function: Transport oxygen

Specialisation:

Does not have a nucleus and organelles
– Maximises the amount of haemoglobin it can accommodate
– Short lifespan (unable to undergo cell division)

Shaped like a biconcave disc to increase the surface area to volume ratio
– allows more oxygen and carbon dioxide to diffuse into the haemoglobin
∴ Allow the RBC to transport oxygen and remove carbon dioxide from all parts of the body effectively

Root hair cell

Description

No chloroplasts
Large surface area to volume ratio
Long protrusion
Large vacuole –> filled with cell sap
Thin cellulose cell wall
Function: absorb water and mineral salts

Specialization:

(Water and nutrients = WN)

Long protrusion increases the surface area to volume ratio of the cell
– more WN can be absorbed through osmosis.

Narrow protrusion also allows the root hair to absorb WN from hard-to-reach areas.

The large central vacuole and thin cell wall help to draw more water from the soil into the cell through osmosis.

∴ Increase the efficiency and amount of WN absorbed by the cell.

Xylem

Description

empty (hollow)
composed of a thickened wall and lignin
Function: transport water

Specialization:

Hollow, walls thickened and waterproofed with lignin
– Strengthens the vessels
– Allows water to pass through freely
– Strong walls give rigidity and support to the plant’s stems

The pits in the walls allow water to diffuse out of the xylem and into surrounding cells.

∴ Allow for quick and efficient transportation of water to all parts of plant

Ciliated cells

Description:

Finger-like extensions (microvilli) at the top of the cell
Intercellular junction
Function: Allows absorption to take place
Specialization:

Microvilli increase the surface area to volume ratio of the cell

∴ Maximises the amount of digested food absorbed by the small intestine

References:

Structure and Function of red blood cells
http://en.wikipedia.org/wiki/Root_hair
Root hair – large central vacuole’s function
Transport in plants – functions of xylem and phloem
Function of xylem – look at comments section as well
What are ciliated cells?

Functions of ciliated cells – why plants don’t have them

http://en.wikipedia.org/wiki/Microvillus

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