Cell Specialisation

Cell differentiation

The developments of cells into specialised types 

Tissues

Group of cells that perform a specific function and have a common origin

Organ

A structure which has a specific function and consists of different tissues

System

Consists of two or more organs 

Palisade mesophyll cell Features (4)

• Large amounts of chloroplasts to absorb light for photosynthesis 

• Cellulose wall to protect the cell and keep it frigid

• Large Vacuole to maintain turgor pressure 

• Found in leaves 

Root hair cell Features (4)

• Found in plant root tips 

• Increases surface area to maximise the movement of water and ions from the soil into the plant root 

• Cell membrane - Partially permeable to water and ions - Contains channels to transport water and mitochondria for the active transport of ions

• Thin cellulose wall to provide short diffusion pathway

• Vacuole with a low water potential to help the movement of water into the cell

• Doesnt contain chloroplasts as the root isnt exposed to light 

Sperm Cell (5)

• They have a tail like structure for movement - undulipodium

• Many mitochondria to produce energy for movement 

• The head has an acrosome containing digestive enzymes 

• When the sperm meets the egg the enzymes are released to digest a protective layer that allows the sperm to penetrate

• Function - fertilise the egg cell delivering genetic information

Egg Cell (4)

• Contain nucleus with genetic material

• Protective membrane called the Zona pellucida

• This layer hardens once sperm enters and becomes impermeable preventing more than one sperm from entering 

• Corona radiata supplies the proteins needed by a fertilised egg cell 

Red Blood Cell (5)

• Known as erythrocytes and produced in the bone marrow 

• Contains haemoglobin - haemoglobin binds to 4 oxygen molecules 

• No nucleus or organelles - increase space for haemoglobin so there is more efficient transport of oxygen 

• Biconcave flexibles discs - squeeze through capillaries and their shape increases surface area to volume ratio

• Haemoglobin molecules are closer to the cell membrane is a short diffusion distance for oxygen and this increases rate of diffusion across plasma membrane

White blood cell

• Produced in the thymus and bone marrow 

• Neutrophils have multi-lobed nuclei to enable them to squeeze through small gaps to reach a site of infection 

• Cytoplasm contains lysosomes that contains enzymes used to digest pathogens during phagocytosis 

• Lymphocytes include B cells which produce antibodies and T cells that work alongside the B cells to destroy pathogens