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8/6/2019 Special is Ed Cells
http://slidepdf.com/reader/full/special-is-ed-cells 1/13
Specialised Cells
8/6/2019 Special is Ed Cells
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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
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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
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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
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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.
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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).
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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
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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
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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
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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
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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.
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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.
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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