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The Fundamental Unit of Life Cheat Sheet (DRAFT) by

for studni rejrrerjen

This is a draft cheat sheet. It is a work in progress and is not finished yet.


Robert Hooke discovered cells in 1665. Leeuwe­nhoek discovered free living cells in pond water in 1674. Robert Brown discovered nucleus in 1831. Purkinje termed 'proto­plasm' in 1839. Schleiden [1838] and Schwann [1839] proposed the cell theory. Virchow expanded the cell theory in 1855. discovery of electron microscope in 1940.


flexib­ility of the plasma membrane enables the cell to engulf food and other materials from its enviro­nment. this process is called endocy­tosis. ex. amoeba
when a living plant cell loses water through osmosis, there is a shrinkage or contra­ction of contents of the cell away from the cell wall. this is called plasmo­lysis.


movement of substances from high concen­tration to low concen­tration until they are spread out
movement of water molecules from high concen­tration to low concen­tration through a semi-p­erm­eable membrane
occurs in any medium
occurs only in liquids
semi-p­erm­eable membrane not reqd
semi-p­erm­eable membrane reqd
can be carried out by dead cells
only living cells carry out osmosis
role of diffusion: gaseous exchange b/w cells & cells and its external enviro­nment.
ex. of osmosis: absorption of water by plant roots, unicel­lular freshwater organisms gain water through osmosis.
ony living cells perform osmosis but dead cell


has higher concen­­tr­ation of water in the medium than in the cell. if we place a cell in it, it gains water and swells up due to endosm­­osis
has higher concen­­tr­ation of water in the cell than in the medium. if we place a cell in hypertonic solution, the cell loses water and shrinks due to exosmosis
has concen­­tr­ation of water same in and outside the cell. if we place a cell in an it, there will be no net movement of water across cell membrane and the cell remains the same size
acc to their chemical compos­ition, diff regions of cells color differ­ently. iodine, safranin & methylene blue solutions.


outermost covering of plant cells. made up of cellulose and is rigid and non-li­ving.
provides protec­tion, shape and structural strength to and freely allows materials to move in and out.
permit plant, fungi & bacteria cells to withstand very dilute external media w/o bursting.


outermost covering of animal cells
outermost covering of plant cells
made up of lipids and proteins
made up of cellulose
flexible and living
rigid and non-living
select­ively permeable membrane
freely permeable membrane
seperates inner contents of the cell from its external enviro­nment, provides protection and shape to cells and allows entry and exit of materials in and out of cells
provides protec­­tion, shape and structural strength and freely allows materials to move in and out


nuclear membrane: double layered covering. separates inner contents of the cell from cytoplasm.
nuclear pores: minute openings in nuclear membrane, allows transfer of material b/w nucleus & cytoplasm.
nucleo­plasm: jelly-like substance containing nucleolus and chromo­somes.
nucleolus: small dark spherical structure composed of RNA and proteins.
chromosome: a thread­-like structure in nucleus known as chromatin reticulum. during cell division, it organizes to form a rod-like structure called chromo­some. it has DNA [funct­ional unit: genes, help in transfer of charac­ter­istics from parents to offspring] and proteins.
controls all activities of the cell, helps in cellular reprod­uct­ion­/cell division & transfer of charac­ter­istics from parents to offspring.


size 1-10nm
size 5-100nm
nuclear region is an undefined nucleus w/o nuclear membrane, containing only nucleic acids [nucleoid]
nuclear region is well defined and nucleus is surrounded by nuclear membrane
single chromosome
more than one chromosome
membrane bound cell organelles absent
membrane bound cell organelles present
ex. blue green algae, bacteria
ex. plant cell, animal cell
unicel­lular organisms: amoeba, chlamy­dom­onas, paramo­ecium & bacteria.
multic­ellular organisms: some fungi [mushr­oom], plants & animals.
chloro­phyll in photos­ynt­hetic prokar­yotic bacteria is associated w/ membranous vesicles but not w/ plastids as in eukaryotic cells.


ribosomes attached to surface
ribosomes absent
helps in synthesis of proteins
helps in synthesis of lipids and fats
seen near nucleus
seen near plasma membrane
ER is a large network of membrane bound tubes and vesicles. it is made up of lipids and proteins.
it serves as channels for transport of materials b/w regions of cytoplasm or nucleus and cytoplasm. acts as a cytopl­asmic framework for various activities of cell. in liver cells of verteb­rates, SER detoxifies poisons and gases.


process of building up of new cell membrane using lipids and proteins synthe­sized by SER AND RER.


membrane bound, vesicles are arranged parallel to each other in stacks [ciste­rns]. often has connec­tions w/ ER. Camillo Golgi.
helps in storage, modifi­cation, packaging and dispat­ching off products in vesicles. complex sugars may be made from simple sugars. involved in formation of lysosomes.


membrane bound sacks filled with digestive enzymes made by RER. waste disposal system of cell. aka 'suicide bags'.
helps keep cell clean by digesting any foreign material and worn out cell organelles


oval shaped organelle having own DNA and ribosomes. surrounded by a double layered membrane. outer membrane porous. inner membrane deeply folded inwards for larger surface area for ATP generating chemical reactions. inner folding is called cristae.
aka powerhouse of cell as it releases energy reqd for various activities of cell [ATP aka energy currency of cell].


colored except green
green coloured
gives color to petals and fruits pollin­ation and dispersal of roots and seeds
help in photos­ynt­hesis
store starch, oil and protein granules
membrane bound organelle having own DNA and ribosomes. chloro­plast contains many membrane layers embedded in the stroma.


storage sacks for liquid­/solid content. small in animal & big [50-90%] in plant cells.
[plant cells] vacuoles are full of sap, provide turgidity and rigidity to cell. store amino acids, sugars, organic acid, & some proteins.
[unice­llular organisms] food vacuoles help in intake & digestion of food and specia­lized vacuoles expel excess water and wastes from cell.


outermost covering: plasma membrane
outermost covering: cell wall
plastids absent
plastids present
vacuoles absent­/small
large vacuoles present
prominent & highly complex golgi apparatus near nucleus
golgi apparatus is in the form of sub-units


occurs in body [somatic] cells
occurs in reprod­uctive cells
1 nuclear division
2 nuclear divisons
chromosome number remains same
chromosome number reduces to half
2 identical daughter cells produced
4 non-id­entical daughter cells produced
helps in growth & repair of tissues in organisms
helps in mainta­ining chromosome number same every generation
process by which new cells are made is called cell division. mitosis: involved in growth & repair of body. miosis: forms gametes.