Special cells and their function

Remember:

Name, Shape and Function

Although all cells share common features, they are designed to do a particular job within an organism.  The structure of each cell relates to its function.

Nerve cell: carries message around the body and has long thin shape.

Red blood cell: have a large cell membrane surface area and are designed to absorbs and carries oxygen across the organism.

Sperm cell:  Fertilises the egg cell and has a long wiggly tail to  facilitate movement. 

Root hair cell: these specialised root cells grow as long thin hairs which spread out into the soil.

This enables the plant to have a  large cell membrane surface area for absorbing water and mineral salts from the soil.

If you were to compare the mineral content of the root hair cell and the surrounding soil, you will find that the root hair cell has more.  From our understanding of diffusion, the root hair cell should loose minerals to the soil instead of gaining from it.  So how does it do it?

It does it by a cleaver process called 'Active Transport'.  This allows the plant to absorb minerals against the concentration gradient.  

Active Transport is very important in a plant as it provides important materials for its growth.

Egg cell: Full of cytoplasm and if fertilised, it develops into an embryo.  

Palisade Leaf cell: Consists of many chloroplasts and carries out photosynthesis. Has a tall shape, which gives it a large surface area for absorbing CO₂ from the air in the leaf. Tall shape also increases the chances for light to hit the chloroplasts.

Guard cell: Their function is to open and close, facilitating the exchange of gases and water vapour. Have a kidney like shape. The gap or pore in the middle of two guard cells is called a Stoma. Stomata (many pores) opens and closes as the cell becomes turgid or flaccid. They are sensitive to light, opening during day-time and closing at night.  Closing during night helps to prevent water losses from the plant. Their thin outer walls and thickened inner walls are ideal for opening and closing function.