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Aleena James

Microscopy is research using microscopes

The magnification of an object is how many times the bigger the image is when
compared to the object. The material is put under microscope (object). And the
appearance of this material when viewed under microscope is referred as image


Page 2

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Aleena James

Tube of filtrate is placed in the ultracentrifuge and spun at a low speed
The heaviest organelle (nuclei) are forced to the bottom of the tube, where
they form a thin sediment or pellet
The fluid at the top (supernatant) is removed and transferred to another tube

Page 3

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Aleena James

Lens is electromagnetic (as electrons are Lens is made up of glass
­vely charged the beam can focus using

Ultrastrcuture of the cell means each cell type has an internal structure that suits for
its job
EUKARYOTIC CELLS have a distinct nucleus and possess MEMBRANE

Page 4

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Aleena James

DOUBLE MEMBRANE- the outer membrane controls movement of material in and
out of organelles. Inner membrane is folded to form extensions known as cristae
CRISTAE- inner folded membrane. these provide large surface area for the
attachement of enzymes involved in the respiration
MATRIX- a semi rigid material containing…

Page 5

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Aleena James

SMOOTH ENDOPLASMIC RETICULUM (SER)- lacks ribosomes on its
surface and is often more tubular in appearence. FUNCTIONS ARE :-
Synthesise, store and transport lipids and carbohydrates

GOLGI APPARATUS- similar to SER in structure except it is more compact. It
consists of a stack of membranes that make up…

Page 6

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Aleena James

Completely breaks down the cell after they've died (autolysis)

Phagocytosis- mechanism by which cells engulf particles to form a vesicle or a vacuole.

RIBOSOMES- small cytoplasmic granules found in all cells. They may occur in the
cytoplas or associated with RER. They are two types:- 80s (found in…

Page 7

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Aleena James

They contain carbon, hydrogen and oxygen
The proportion of oxygen to carbon and hydrogen is smaller than in
They're insoluble in water
They're soluble in organic solvemts such as alcohols and acetone
The main groups of lipids are triglycerides, phospholipids and waxes


Page 8

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Aleena James

They form a bilayer sheet. They're very important because:-
One layer has its hydrophilic heads pointing inwards (interacting with water in
One layer with hrdrophobic heads pointing outwards (interacting with water
which surrounds all cells)
The hydrophobic tails of both phospholipid layers point into the centre of…




This is a concise set of notes with clear diagrams and micrographs which would be useful to all A level biology students studying cell structure. It would be useful to make your own set of flashcards from this information that could be downloaded and used to test yourself with. 



Excellent set of well detailed notes, proving to be a huge help in my revision efforts! :D

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