special is ed cells

8/6/2019 Special is Ed Cells

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Specialised Cells



Sperm Cell

The sperm cell (male gamete)- designed to fertilise eggs

A sperm cell is very small and has alittle tail/flagellum which

provides movement so it can swimand find an egg to fertilise ²Packed with mitochondria

Its head contains enzymes (in thevacuole) which allow it to digestits way through an egg membraneso the two nuclei can join

It contains half the number ofchromosomes in the nucleus -these carry genetic informationfrom the father, which will bepassed on to the offspring



Ovum CellThe ovum cell (femaleGamete)- designed to befertilised

An ovum is large and bulky becauseno active movement is needed - it just sits and waits for the sperm

to find it

It contains yolk (in the cytoplasm)which provides a large food storeneeded for the developing youngorganism once it's fertilised

It contains half the number ofchromosomes, which carrygenetic information from themother - this will be passed on tothe offspring



Red blood CellThe red blood cell ² carriesoxygen

Thin outer membrane allows oxygento diffuse through easily.

Bi-concave shape increases thesurface area to allow moreoxygen to be absorbedefficiently.

No nucleus means that the wholecell is full of haemoglobin whichcombines with and carries oxygen

around the body.Bi-concave shape, i.e. thinner in the

middle, the more flexibleframework allows cells tosqueeze through even the tiniestcapillaries



White blood CellThe white blood cell ² fights disease

Irregular shape, some with many lobed nuclei.

Can change shape to squeeze out of bloodvessels and get to the site of infection.

Some make antibodies.

Others have cytoplasm which can flow makingit possible for the cell to change shape,

surround and engulf bacteria.

Can increase in numbers to fight disease.



Nerve CellNerve cell ² Passes sensoryimpulses from receptor toeffector

Dendrites to make connections withother neurones.

Long axon or nerve fibre to carrythe impulse to the target organ.

End plate forms a synapse with aneffector (a muscle or a gland).



Ciliated Cell

The cilia cell - designed tostop lung damage

Cilia cells line all the airpassages in your lungs

They have tiny hairs (cilia),which filter the air as itblows through

The hairs sweep mucus withtrapped dust and bacteria upto the back of the throatwhere it is swallowed



Muscle Cell

TheMuscle cell ² allowsskeletal movement

Elongated in shape.

Have fibres which slide into eachother and cause the muscle tocontract or become shorterand then relax to its originallength.

Contain filaments of muscleproteins.

Need energy to work thereforehave a lot of mitochondria



Palisade Cell

The palisade cell - designedfor photosynthesis

A palisade cell is tall with a largesurface area

It's found on the top side of a leaf -ideal for good absorption ofcarbon dioxide and light - bothare needed for photosynthesis

They're packed with chloroplasts,

which contain the green pigmentchlorophyll, which is needed forphotosynthesis



Guard CellThe Guard cell ² helps to reduce waterloss

Surround stoma in the outer layer of leaves.

Predominate on the lower surface of the leafto reduce water loss.

Cell wall closest to the pore is thicker andless flexible.Have chloroplasts and carry outphotosynthesis.

Consequent changes in glucose concentration

and osmotic potential allow water to enterand leave.

When turgid, guard cells pull the thickenedwall in, opening the stoma



X ylem Cell

The X ylem cell ² carries water fromroots to leaves

Long and tube-like hollow vessels.

Cells have no end walls, so form a 'pipeline'carrying water from leaves to root.

Spirals and rings of lignin strengthen the

walls, to withstand pressure of water.



Phloem Cell

The Phloem cell ² Carries sugarsfrom leaves

Living cells with perforated end walls, hencethe name sieve tubes.

Have vertical strands of cytoplasm whichcarry glucose and other sugars dissolvedin water to growing and storage areas ofthe plant.



Root Hair Cell

The root hair cell - designed forabsorbing

The long hair cell increases thesurface area of the root, which

helps absorption of water andminerals

It has a really thin cell wall, whichmakes it easier for minerals topass across into the root itself

special is ed cells

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