cytoplasm & cell organelle's structure, types and their important functions

1. Cytoplasm

2. Cytoplasm
Cytoplasm
Cytosol/Matrix Cell organelles Cell Inclusions
(Hyaloplasm)
(fluid part of cytoplasm)
• Mitochondria
• Plastid
• Endoplasmic reticulum
• Golgi complex
• Lysosomes
• Ribosomes
• Micro bodies,
Microtubules &
Microfilaments
• Centriole
• Centrosomes
• Vacuoles
• Cilia & Flagella
• Reserve material
• Secretory material
• Excretory material

3. Cytosol/Matrix/ Hyaloplasm
• Composition : Inorganic compounds – water(75- 85%), salts of
Na, K & other metals.
Organic compounds – carbohydrates, lipids,
proteins, nucleoproteins, nucleic acids, enzymes etc.
• Pheripheral (outer, near plasma membrane) layer is non-granular,
viscous, clear & rigid so called plasma gel or ectoplasm or cortex.
• Inner layer is granular, less viscous called plasma sol or endoplasm
or medulla.
• Functions : provides raw material for cell organelles, site of
biosynthesis of lipid, nucleotides, proteins etc., site of glycolysis
(glucose pyruvic acid i.e. glycolosis).

4. Cyclosis
• It is an active movement of cytoplasm around vacuole or the
movement of food vacuole in cytoplasm(In Paramecium).
• Also called cytoplasmic streaming.
• It helps in,
 Movement of cell organelles e.g. food vacuole in Paramecium.
 Distribution of materials inside cells
 Formation of pseudopodia in Amoeba.

5. Mitochondria (GK mito: thread, chondrion: granule)
• Discovered by Koliker in 1880 AD, later on 1890 AD Altman named it as
Bioplast.
• The term Mitochondria was given by C. Benda in 1898 AD.
• Commonly called “power house of cell”.
• Absent in prokaryotes, present in all eukaryotic cells except mature
mammalian RBC & sieve tube of phloem in vascular plants.
• Mitochondria contains enzymes, protein(70 %) , lipids(25-30%), 0.5% of
RNA & traces of DNA(1%).
• Shape : Rod shaped, Filamentous, Spherical, Oval, Cylindrical or can
change its shape depending upon the condition of cell.
• Size : Size varies from cell to cell.
Yeast cell =1µm3 (smallest) , Toad =20-40µm3(largest).
• Number : variable, found more on growing, dividing & metabolically active
cells. E.g. In Chlamydomonas = 1, Muscles of insects = 500,000 per cell.
• Location : It is located in metabolically active area where energy is required
continuously.

6. • Ultrastructure of Mitochondria
Inter cristae space
Inner chamber

7. • Mitochondria is bounded by a double layered membrane i.e. Inner &
outer membrane.
• Space between inner and outer membrane is called outer chamber,
filled with watery fluid.
• Inner membrane is filled with a matrix which contains inorganic salts,
ribosomes & DNA.
• Outer membrane is smooth. Inner membrane is folded into a
number of folds called cristae, which increases the surface area for
cellular respiration.
• Cavity inside cristae is called Inter cristae space.
• On the matrix, there are numerous tennis racket like structure known
as Oxysomes (F1 particles or elementary particles). In the head of
these particles ATP synthetase is present which controls the synthesis
of ATP, so these are also called ATP particle.

8. Functions of mitochondria
• They are “power house of cell” as they store energy in the form of
ATP in oxysomes.
• It helps in cellular respiration.
• It is the site of Krebs cycle or TCA cycle i.e. conversion of pyruvic
acid into ATP.
• They can synthesize some amino acids.
• Regulate the Ca+ ion concentration inside the cell.
• Helps in yolk formation in ovum.
• It also forms middle part of sperm.
• It is the site of synthesis of haeme of haemoglobin & myoglobin.
(a protein found in the muscle tissue of vertebrates)

9. Plastid
• They are double membrane bound cytoplasmic organelles found in plant
and some protozoans such as Euglena.
• They are absent in bacteria, blue green algae(cyanobacteria), fungi but may
contain chromatophore. Plastid may be coloured or colourless.
• The term plastid was given by Haeckel (1886 AD).
• Types, there are 3 types of plastid, Chloroplast
Chromoplast &
Leucoplast.
 Chloroplast (GK, chloros=green, plastos=formed)
• Most common plastid, they have green pigment called chlorophyll.
chloroplast was first observed by Anton Von leeuwenoek in 1697.
• The term chloroplast was given by Schimper in 1883 AD.
• It is found in all photosynthetic cells of plant.
• Shape : Biconvex in higher plants, however it may be filamentous, saucer
shaped, ovoid, discoid, spheroid, star, spiral etc.
• Size : Usually measures 2-3µm in thickness & 50-10µm in diameter but size
may vary.
• Number : Chlamydomonas = 1, Spirogyra = 1-16, In higher plants may
present 20-40 per cell or may be up to 500 per cell.

10. Ultrastructure of Chloroplast
Fig : Ultrastructure of chloroplast

11. • Bounded by double layered membrane, outer & inner lipo-protenious
membrane with an inter membrane space between them.
• Inner membrane contains two parts, grana & stroma (matrix).
• In stroma or Matrix, dark reaction of photosynthesis takes place. It
contains proteins(> 50%), mRNA, circular DNA, tRNA, ribosomes,
water, Mn2+
, Fe2+, Mg2+, ATP particles & enzymes.
• Grana are embedded in stroma. Light reaction of photosynthesis
takes place in grana. Each granus contains disk shaped membranous
sac called thylakoid. Each grana are connected by a network of
membranous tubules called Intergrana or Stroma lamellae or Frets.
• Grana or thylakoids contains all types of enzymatic components
required for photosynthesis.

12. Functions of Chloroplast
• Chloroplast helps in photosynthesis as it contains chlorophyll.
Chloroplast are the “kitchen of cells”.
• They evolve oxygen during photosynthesis, balance O2 & Co2 in
biosphere, prevent global warming by reducing Co2, they maintain
nature greenery.
• They store starch in protein body called Pyrenoids in
algae.(Spirogyra)

13.  Chromoplast (GK, chroma=colour, plastos=formed)
• They are coloured plastids which contains various pigments other than
green.
• They make fruit & flowers attractive to attract insects for pollination.
• Types,
 Phaeoplast(dark brown pigments) – E.g. xanthophyll & Fucoxanthin,
found in diatoms, dinoflagelates & brown algae.
 Rhodoplast(red pigments) – E.g. R-phycoerythrin & R-phycocyanin,
found in red algae.
 Chromatophore in blue green algae. E.g. C-phycoerythrin, C-
phycocyanin & chlorophyll-a.
 Chromatophore of photosynthetic bacteria. E.g. carotenoid.

14.  Leucoplast(GK, leuos=white, plastios=formed)
• They are colorless plastid. They are found in parts which are not
exposed in sunlight.
• They store & reserve food(starch).
• Types,
 Amyloplast : they store starch, found in potato tubers, wheat & rice
grains.
 Elaioplast or Oleosome or Lipoplast: they store lipids, found in
sunflower, mustard, ground nut, olive etc.
 Proteinoplast or Aleuroplasts : they store protein, found in seeds.

15.  Semi-autonomous nature of Mitochondria & Chloroplast
• Mitochondria & chloroplast contains all requirement for protein
synthesis i.e. ribosomes, DNA molecule which can transcript into
RNA (Transcription : DNA mRNA) & ATP molecule & it can
replicate or make its copy of itself during cell division. Thus they are
semi-autonomous cell organelles.

16.  Endoplasmic reticulum (ER)
• ER was first observed by Garnier (1897 AD), its ultrastructure was given by Porter,
Claude & Fulham (1945 AD), the term Endoplasmic reticulum was given by Porter
(1953AD).
• ER is present in all cells except germinal cell & mature mammalian RBC. Absent in
prokaryotic cell.
• Types,
 Smooth or agranular endoplasmic reticulum(SER) : ribosomes absent.
 Rough or granular endoplasmic reticulum(RER) : ribosomes present.
• Structure : composed of three types of structure, Cisternae, Vesicle & Tubules.
Cisternae : long , flattened, sac like , narrow,
two layered, un-branched tubules near nucleus,
40-50µm in diameter & contains ribosomes on
the membrane.
Vesicle : oval, membrane bound structure
having diameter about 25-500µm. They
remains often scattered on cytoplasm.
Tubules : wider, tubular & branched forming
reticular system around Cisternae & Vesicle.
They are about 50-190µm in diameter.

17. • Functions,
 ER acts as cell circulatory system. It helps in the transport
of material.
 It also acts as cytoskeleton providing mechanical support.
 It helps in the storage of glycogen, protein synthesis, lipid
synthesis, synthesis of hormones.
 Helps in the formation of primary lysosomes.
 Helps is the synthesis of nuclear membrane during cell
division.
 Helps in detoxification of harmful drugs.

18.  Golgi Complex
• Discovered by Camillo Golgi in 1898 AD in the nerve cell of cat & barn owl.
• It is also called Lipochondrion or Idiosome or Dalton complex or Dictyosomes.
• Absent in prokaryotic cell. Occurs in all eukaryotic cell except mature mammalian
RBC, antherozoids of bryophyta & pteridophyta & sieve tubes of phloem of
angiosperm.
• Shape & size varies according to the cell, present in large numbers in plant cells.
• Structure, Under electron microscope golgi body consist of three smooth
membranous compartments such as; Cisternae or flattened sac, Vacuoles &
Vesicles.
Cisternae or flattened sac : they are elongated,
double layered, flat & curve parallel sac with
swollen ends. They are about 180-230A0 in size.
They are about 3-12 in animal cell & 10-20 in
plant cell.
Vacuoles : They are spherical & lies infornt of
cisternae.
Vesicle : small structure associated with
cisternae & vacuoles. They may be smooth &
coated types.

19. Functions of golgi body
• Helps in cell excretion.
• Balances the fluid inside cells.
• Helps in cytokinesis(division of cytoplasm) during cell division.
• Helps is the formation of primary lysosome.
• Helps is the formation of hormones in endocrine cells.
• Golgi body of intestine helps in the absorption of lipid.

20.  Lysosomes(GK, lysis=digestive, soma=body)
• Discovered by Christain de Duve in 1955 AD in the liver cells of rat.
• They are involved in intra cellular digestive activities. They contains digestive or
hydrolysing enzymes capable of lysis or digestion . So they are called suicidial
bags.
• Present in all eukaryoic cells except mammalian RBC, some fungi (Yeast), Euglena
& meristematic cells.
• They are spherical or irregular. Size ranges from 0.2-0.8µm. Average size is 0.5µm.
• Lysosome contains 40 types of enzymes divided into six categories, protease,
nuclease, glycosidase, phosphatase, sulphatase & esterase.
• Lysosomes are of 4 types; Primary, secondary, Autophagosome (autolysosomes)
& Residual bodies (tertiary lysosome or telolysosome).
 Primary lysosome; are small sac like bodies. They have digestive enzymes in
inactive forms.
 Secondary lysosomes; made by fusion of primary lysosome with other extracellular
or intracellular material. It contains ingested food & digestive enzymes.
 Autophagosome; formed when cells feed upon intracellular organelles such as
mitochondria & ER.
 Residual bodies; are lysosomes with undigested food, they are generally thrown out
of cell by exocytosis.

21. Functions of lysosomes,
• Autophagy; digestion of reserve food or cell organelles.
• Heterophagy; digestion of foreign food particles.
• Autolysis; self destruction of cell by the release of digesting enzymes.
Because of autolysis lysosomes are called suicidal bags.
• Defense against pathogens.
• Can engulf carcinogens (cancer causing agents).

22.  Ribosomes
• First isolated by Claude in 1943AD & named “Microsomes”. These
were first reported by Robinson & Brown (1953AD) in plant cells &
were called “ribosomes” by G. Palade in 1955 AD.
• Found in all cells(prokaryotic & eukaryotic) except mature sperm cell
& RBC.
• They are found freely(in prokaryotes) or remains attached on ER.
They are “The site of protein synthesis”.
• In Eukaryotic cells ribosomes are found in two forms, in cytoplasm
(cytoplasmic ribosomes) i.e. free form and bound form(RER & outer
nuclear membrane).
• They are also found inside some cell organelles like mitochondria &
plastids.
• Shape : sphere, dome or cap like shape.
• Size : 70s=200-290A0 × 170-210A0 ; 80s=300-340A0 × 200-240A0
• Number : depends upon the RNA content of cell, ribosomes are more
on plasma cells, liver cells, meristematic cells, cancer cells, endocrine
cell. Escherichia coli contains 20,000-30,000 ribosomes.

23. • Types & structure,
 70s ribosomes : smaller in size , found in prokaryotic cell, they have sedimentation
coefficient 70s and molecular weight 2.7 ×106 daltons. (70s = 30s & 50s) .
 80s ribosomes : larger in size, found in cytoplasm of Eukaryotic cell, they have
sedimentation coefficient 80s & molecular weight 4.5 ×106 - 5.0 ×106 daltons.
(80s=40s & 60s). 40s & 60s
[1 dalton = 1.65 ×10-24 gm]
 Larger subunit 50s & 60s are dome shaped & attached to ER by glycoprotein.
 Smaller subunit 30s & 40s are oval shaped & fits into the cap on flat side of larger
subunit. It is the binding site of mRNA.
 When many ribosomes are attached to mRNA it is called polysome or
polyribosome.
Functions,
Site of protein synthesis,
protein factories of cells, stores
proteins.
Synthesize enzymes for intracellular
& extracellular use.

24.  Vacuoles (latin, vaccus=empty sac)
• Single membrane cell organelles bounded by a tonoplast, fluid filled
sac.
• Plant cell contains larger vacuoles while in animal cell small vacuoles
are present.
• Structure,
 Vacuole has two parts, Tonoplast & cell-sap.
 Tonoplast is outer layer, lipoprotenious, selectively permeable
membrane about 40A0 in thickness.
 Cell sap is a fluid present inside vacuole, it contains water, minerals,
sugar, amino acids, proteins, waste products etc.
• Functions,
 Stores water, minerals & organic compounds
 Helps in digestion(food vacuoles), osmoregulation(contractile
vacuoles) in protozoans.
 Gas vacuoles provides buoyancy in prokaryotes.

25.  Centrioles, Basal bodies & Centrosome
• Centrioles are small hollow structure present in animal cell, absent in
plant cells.
• Centrosomes are formed by two darkly stained granules of centrioles
surrounded by a transparent centrosphere or cytocentrum. As
centriole are found in pairs so called diplosome.
• They are found in the base of cilia & flagella called basal bodies.
• They are found in protozoans, algae & all animal cells except mature
mammalian RBC & prokaryotes.
• Functions, controls the movement of cilia & flagella, helps in the
formation of spindle fibres.

26. • Microbodies;
- Sphaerosomes : small spherical bodies, helps in lipid metabolism.
- Peroxisomes : circular shaped, protects cell organelles from toxic
substances, involve in oxidation of fatty acids.
- Glyoxysomes : spherical shaped, helps in carbohydrate metabolism
• Microtubules (Neuro-tubules) : They are slender protein tubes or
threads, found in cilia, flagella , nerve cells, meristematic cells etc.
They provide mechanical support to cell, helps in spindle fibre
formation, locomotion, feeding, distribution of coloured pigments in
cells, carry nerve impulses.
• Microfilaments :They are long, thin & fine protein filaments present
in muscle fibres. They help in cyclosis, locomotion, movement,
absorption, endocytosis, helps in cleavage during cell division.
• Cilia & flagella : They helps in movement(flagella in bacteria, cilia in
Paramecium), food capturing(Paramecium), cilia of kidney(nephrons)
moves the filtrate, in respiratory tract cilia helps in elimination of
solid particles, cilia of larva helps in their dispersal, eggs of amphibian
& mammals are driven out from oviduct by cilia.

27.  Nucleus
• Nucleus is the “Brain of cell”, it is the most significant cell
organelles which controls all the cellular activities of cell &
carries the heriditary information.
• It was first described by Robert brown in 1831 AD in orchid cell
(Nepali name : Sunakhari or Sungava).
• It was first observed by Anton Von Leeuwenhoek.
• Occurrence :
- found in all eukaryotic cell except mature mammalian RBC,
sieve tube of phloem, tracheids & vessels of xylem contains true
nucleus.
- all prokaryotic cell contains incipient nucleus or nucleoid or
prokaryon or genophore i.e nucleus without nuclear
membrane & nucleolus.

28. • Number :
- Uninucleate (monokaryotic cell) : single nucleus e.g.
oesteoblast cell, simple plant & animal cell, some fungal
cell etc.
- Binucleate cell : two nuclei e.g. Paramecium(macronucleus
& micronucleus), cancer cells, liver cells, cartilage cells etc.
- Polynucleate/ multinucleate cells : many nuclei e.g.
Rhizopus (fungi), Vaucheria (green algae).
• Shape & Size :
- varies from cell to cell. It may be spherical, cuboidal,
ellipsoidal(depressed sphere), discoid or even irregular.
- In young cell it occupies about 25% & in mature cell it
occupies about 10% of cell volume.

29. Ultra-structure of Nucleus
Ribosomes
ER
Outer membrane
&
Inner membrane
Peri-Nuclear Space
Nucleolus or Plasmasome
Chromatin Network or reticulum
Heterochromatin
Nucleoplasm/Nuclear sap
Nuclear Pore(Annulus)
Euchromatin
Fig : Ultra-structure of Nucleus
Nuclear membrane or Karyotheca

30. • Ultra structure of Nucleus shows following parts,
- Nuclear membrane/ karyotheca
- Nuclear sap/ nucleoplasma
- Chromatin fibre/ nuclear reticulum
- Nucleolus/plasmasome
• Nuclear membrane :
 It is a thin, transparent membrane, discovered by Erclab in 1845 AD.
 Composed of two membranes inner & outer membrane. Space
between inner & outer membrane is called peri-nuclear space filled
with fluid.
 Outer membrane is continuous with RER.
 It contains nuclear pore, it helps in the exchange of material between
nucleus & cytoplasm. Pore is fitted with a cylindrical structure called
Annulus & forms pore complex or pore basket.
 Function : It provides definite shape & size to nucleus, helps in
passage of organic & inorganic nutrients, helps in phagocytosis &
pinocytosis.

31. • Nuclear Sap :
 It is a homogeneous, semi fluid & transparent gel.
 Composed of water, nucleotides, sugars, minerals, proteins,
ribosomes, lipids, mRNA, tRNA etc.
 It also contains basic proteins, which take basic stain(dye)
e.g. nucleoprotamines, nucleohistones and acidic
proteins(non histones proteins) e.g. phosphoprotein.
 Functions : It maintains definite shape & size of nucleus,
provides nutrients, supports nucleolus & chromatin fibers, it
is the site of enzyme activities.

32. • Chromatin fibers: (GK, chroma=colour)
 It is a thread like, coiled & elongated structure.
 It forms network called chromatin reticulum.
 It was first observed by W. Fleming (1882 AD).
 It is of two types,
 Heterochromatin : darkly stained, occurs around nucleolus &
periphery, it is metabolically innert, it contains large amount of
RNA & less amount of DNA.
 Euchromatin : light in colour, contains large amount of DNA, it
is metabolically & genetically active.
 Chromatin threads shows beaded structure due to dense region
of DNA & proteins called Chromomeres.
 During cell division chromatin fibre condense by dehydration &
spirilization into short rods like structure called chromosomes.

33. • The term chromosome was given by Waldayer(1888 AD).
• It is a thread like filamentous body, heriditary in structure, it
store replicate & transmit cooded information of biological
importances.
• Chromosome is composed of 50% protein & 50% DNA.
• Humans= 23 paris(2n or diploid) of chromosomes, 22 paris are
similar in male & female called Autosomes or Homologous
chromosomes.
• 23rd pair is sex chromosome, in female=XX & in male=XY.
• “X” chromosome is rod shaped while “Y” chromosome is “J”
shaped.
• Pea(Pisum sativum)=14 pairs
• Carrot(Daucus carota)=18 pairs
• Maize(Zea mays)=20 pairs
• Onion(Allium sepa)=16 pairs
• Nematode worms= 2 pairs
• Protozoans=300 in each cell

34. • Structure & function of
chromosomes
 Chromosome is covered externally by a
pellicle which contains matrix inside.
 In matrix chromonema is present which is
composed of two sub chromatids called
chromonemata.
 Tips of chromosome is called telomere, it
prevents the end of chromosome from
sticking together.
 Secondary constriction II is the site of
breakage & subsequent fusion.
 Secondary constriction I (nucleolar
organizer)is necessary for the formation of
nucleolus.
 Primary constriction or centromere is
functional during cell division.
 Satellite is the part below secondary
constriction I. It is sphere shaped & short. It
contains SAT- chromosome(sine acid
thymo nucleinico). It serves as identifying
markers for secondary constriction.
Telomere
Secondary constriction II
Secondary constriction I
(nucleolar organizer)
Primary constriction(Centromere)
Pellicle
Matrix
Chromonema
Satellite
(Contains two
Chromonemata)

35. • According to the location of centromere chromosome are of
following types,
• Functions of chromosome
 It contains DNA which acts as genetic material & transfer it
to offspring.
 Controls the synthesis of proteins.
 Helps to produce variation through DNA.

36. • Nucleolus :
It is a spherical, dark coloured granule. It has three
regions, granular, fibrillar & amorphous regions.
It is composed of RNA & non-histones acidic proteins.
Functions : It stores & synthesize RNA, helps in spindle
fibre formation, helps in the synthesis of nuclear
protein.
• Functions of Nucleus :
Controls cellular activities.
Helps in cell division.
Controls the synthesis of proteins.
Helps in ribosome formation.
Transfer hereditary character.
Helps in genetic variation.

37. Cell inclusions
• As a result of metabollic activities, several kinds of non-
living substances are produced within the cell, called cell
inclusions or deutoplasmic bodies or Egrastic bodies. E.g.
proteins, starch, cellulose, organic acids, Nectar, Resins,
oils, plant pigments etc.
• 3 types, Reserve materials, Excretory material &
Secretory materials.
• Reserve materials : stored product inside cells.
E.g. – carbohydrates : glucose, fructose, sucrose, Starch
grains, inulin(soluble polysaccharide), pectin, cellulose,
glycogen.
- Nitrogenous matter : proteins & amino acids
- Fats & oils

38. • Excretory materials : waste products of plants, not useful
for plants but valuable for human.
E.g. – Tannins(bitter compound found in bark , leaves, fruit ,
seeds. Used to manufacture ink & for tanning of leather).
- Resins (found in stem of pine, used in paints & varnishing).
- Latex(white milky substance produced by lactiferous cells
of Rubber plant).
- Gums(produced by cellulose )
- Alkaloids (nitrogenous substance found in root, seed , bark
& leaf, used in medicines).
- Essential oils(found in leaf, used to manufacture oil, soaps,
perfume etc.)
- Organic acids(found in citrus fruits).

39. • Secretory materials : secreted by protoplasm.
E.g. – Nectar
- Plant pigments(E.g. Anthocyanins, anthoxanthins,
chlorophyll-a, b, c ).
- Hormones & enzymes(promotes growth & development).