This document provides an overview of prokaryotic and eukaryotic cells, including their structures and functions. It begins by defining prokaryotic and eukaryotic cells based on the presence or absence of nuclei. The main structures and characteristics of prokaryotic cells are described, including the cell wall, plasma membrane, mesosomes, ribosomes, and circular DNA. Key structures of eukaryotic cells are also outlined, such as the nucleus, mitochondria, Golgi bodies, endoplasmic reticulum, and linear DNA. The structures of plant and animal cells are compared. Finally, similarities and differences between prokaryotic and eukaryotic cells are summarized.

1. Prokaryotic and Eukaryotic
Cell : Structure and
Functions
SUBMITTED BY :- GUIDED BY :-
ADITI CHANDRAKAR DR. JAISHANKAR PAUL
M.SC. 1st SEMESTER
BIOTECHNOLOGY
SCHOOL OF STUDIES
BIOTECHNOLOGY
PT. RAVISHANKAR SHUKLA UNIVERSITY 1

2. CONTENT
 Introduction
 Prokaryotic cell: characteristics
 Structure & functions of Prokaryotic cell
 Eukaryotic cell: characteristics
 Structure & functions of Eukaryotic cell
 Difference between plant & animal cell
 Comparision of Prokaryotic & Eukaryotic cell
 Similarities between Prokaryotic & Eukaryotic cell
 References
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3. INTROUCTION
 On the basis of presence or absence of nucleus
the cell are classified into two main types:
i) Prokaryotic cell
ii) Eukaryotic cell
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4.  Prokaryotic cell:-
( pro= before, karyon = nucleus)
 “Prokaryotic cells are the cells that do not have a
true nucleus and membrne-bound organelles.”
 E.g. Bacterial cell, PPLO etc..
 Eukaryotic cell:-
( Eu= true , karyon= nucleus )
 “Eukaryotic cells are the cells that contain
membrane-bound nucleus and organelles.”
 E.g. Protists, fungi, plants and animal cells
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5. PROKARYOTIC CELL
 Prokaryotic cells are single-celled (unicellular)
microorganisms known to be earliest on earth.
 Oldest type of prokaryotic cell appeared
approximately 3.5 billion years ago.
 Prokaryotic cell are simplest type of cell.
 Prokaryotes are the largest group of organisms.
 They are found in all environments.
 Prokaryotes includes Eubacteria and Archaebacteria
(Halophiles, Thermophiles, Methanogens).
 Photosynthetic prokaryotes includes Cyanobacteria
that perform photosynthesis.
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6. Characteristics of prokaryotic cells
:
 Prokaryotic cell lack nuclear membrane, nucleolus,
due to which DNA and RNA remain dispersed
throughout the cytoplasm.
 Mitochondria, Golgi body, Chloroplasts, Endoplasmic
reticulum and Lysosomes are absent.
 The genetic material is present on a single
chromosome.
 The cell wall is made up of carbohydrate
(polysaccharide) and amino acids.
 Ribosomes are 70S type (subunits 50S + 30S type)
 Nucleus is known as nucleoid
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7.  Prokaryotes are smaller in size when compared to
eukaryotic cells.
 Infoldings of plasma membrane inside the cytoplasm
is found which is known as mesosome and perform
the function of mitochondria.
 They divide asexually by binary fission.
7

8. Prokaryotic cell: structure and their
functions
1) Glycocalyx :- It is the outermost protective covering
followed by cell wall and then plasma membrane.
 It could be loose sheath called slime layer in some,
whereas in others it may be thick and tough called
capsule.
 Functions :- It helps in moisture retention, protects
the cell when engulfed (phagocytosis) and help in
the attachment of cells to nutrients and surfaces.
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9. 2) Cell wall :- Bacterial cell wall is rigid and strong
structure.
 Functions :- Cell wall determines the shape of the
cell and provide a strong structural support to
prevent the bacterium from bursting or collapsing.
3) Cell membrane :- This layer is semi-permeable in
nature and surrounds the cytoplasm .
 This membrane is similar structurally to that of the
Eukaryotes.
 Functions:- It interacts with outside world and
regulate the entry and exit of substances in the cell.
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10. 4) MESOSOME:- It is formed by extension of plasma
membrane into the cytoplasm.
 Mesosomes are analogus to mitochondria.
 Function:- It helps in cellular respiration.
5) CYTOPLASM:- It is a jelly like substance present
inside the cell membrane.
 All the organelles are suspended in cytoplasm.
6) PILI:- These are hair-like outgrowths that help the
bacterium to attach to the surface of other bacteria.
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11. 7) FIMBRIAE:- are small bristle like fibres sprouting out
of the cell.
 Function :- Help to attach the bacteria to the rocks in
streams and also to the host tissues.
8) FLAGELLA:- are long filamentous appendages
consisting of a hook, filament and basal body.
 Function :- Helps in locomotion
9) RIBOSOMES :- 70S ribosomes (two subunits 50S &
30S) are present in prokaryotic cell.
 Function :- Involve in protein synthesis.
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12. 10) NUCLEOID :- It is the region in the cytoplasm where the
genetic material is present.
11) DNA :- is the genetic material of the cell.
 Function :- It directs what protein should the cell create
and regulates the action of cell.
12) PLASMID:- are self replicating , circular, extra
chromosomal DNA structures.
 Plasmids are not involve in reproduction.
13) INCLUSION BODIES:- Reserve materials in prokaryotic
cells are stored in the form of inclusion bodies
e.g. phosphate granules, glycogen granules etc..
12

13. Diagram of a typical prokaryotic
cell: bacterial cell
13

14. EUKARYOTIC CELLS
 Eukaryotes arose from prokaryotes and developed
into larger and more complex organisms.
 Eukaryotic cells appeared approximately one billion
years ago.
 Eukaryotes include some unicellular protists to
multicellular fungi, plants and animals.
 These have a nucleus enclosed within the nuclear
membrane.
 Eukaryotic cells are generally more advance than
prokaryotic cell.
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15. CHARACTERISTICS OF EUKARYOTIC
CELL :-
 Eukaryotic cells have complex internal structure.
 They have the nucleus enclosed within the nuclear
membrane and nucleolus is also present in the
nucleus.
 All the cell organelles (mitochondria, endoplasmic
reticulum, ribosomes, golgi body, vacuoles etc..)are
present in the cytoplasm.
 Flagella and cilia are the locomotory organs in a
eukaryotic cell.
 Ribosomes are of 80S type (subunits 60S + 40S
type)
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16.  Cell wall made up of cellulose is present in plant cells but
completely lacking in animal cells.
 Cells contain a cytoskeletal structure.
 Eukaryotic cells divide by mitosis.
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17. EUKARYOTIC CELL :- STRUCTURES
AND THEIR FUNCTIONS
Plasma membrane/cell membrane
 Plasma membrane is a thin, elastic, transparent semi-
permeable membrane, found in all cells.
 Functions :- Transport of water, molecules and ions.
 It acts as a protective layer around the protoplasm of the
cell
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18. Cell wall
 Cell wall is the outermost rigid structure present outside the
plant and fungal cells.
 It is absent in animal cells.
 Function:- It provide definite shape to a cell and helps in
cell-to-cell interaction.
 It acts as a protective layer that protects the cell from any
injury or pathogen attack.
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19. Cytoskeleton
 In eukaryotic cell microfilaments and microtubules together
constitute cytoskeleton which provide perfect shape to cell and
also give mechanical support to the cell.
 Function:- Helps in cyclosis of protoplasm.
 Involved in movement of cell.
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20. ENDOPLASMIC RETICULUM
Endoplasmic reticulum is a complex network of tubular membranes
exclusively present in the cytoplasm of the eukaryotic cell.
 Endoplasmic reticulum is of two types:-
(i) Rough endoplasmic reticulum:- contains ribosomes
(ii) Smooth endoplasmic reticulum:- lacks ribosomes
 Functions:- Provide more surface for metabolism, helps in the transport
and intracellular circulation.
 Also helps in protein synthesis.
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21. Nucleus
 Nucleus is a double membrane bound organelle
which directs and control all the cellular functions
and also contain genetic material.
 Nucleus consists of :-
(i) Nuclear membrane
(ii) Nucleoplasm
(iii) Chromosomes
(iv) Nucleolus
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22. Golgi apparatus
 Golgi body is made up of flat disc-shaped structure called cisternae and
are arranged parallel and concentrically near the nucleus.
 Functions:- Important site for the formation of glycoproteins and
glycolipids.
 It is mainly involved in modifying, sorting and packaging of cell products
into secretory vesicles.
.
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23. RIBOSOMES
 Ribosomes are tiny granules composed of mRNA
and protein.
 Function:- Main site for protein synthesis
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24. Lysosome
 Lysosomes are vesicular bodies filled with hydrolytic
enzymes and are involved in digestion of protein, lipid,
carbohydrate and nucleic acid.
 They are also called as “Suicidal bags”.
 Functions:- Dead cells inside the body are removed by
lysosomes.
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25. Cytoplasm
 Cytoplasm consists of jelly-like homogenous ground
substance.
 It contains cell organelles and inorganic material.
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26. MITOCHONDRIA
 Mitochondria is a double membrane bound organelle.
 It is also known as “ power house of the cell” because they
produce energy.
 Functions:- Principle organ for the cellular respiration. .
 Produce cellular energy in the form of ATP.
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27. PLASTIDS
 Plastids are the double membrane bound organelle
and are only found in plants.
 Based on the type of pigments, plastids are of three
types:-
(i) Chloroplast :- Greenish colour plastids containing
chlorophyll.
(ii) Chromoplast:- contains a pigment called carotene that
provides plants yellow , red or orange colour.
(iii) Leucoplast:- are colourless and store lipids,
carbohydrate or protein. 27

28. Cilia and Flagella
 Cilia and Flagella :- Hair-like projections covered
with plasma membrane with core of axoneme (9+2
array).
 Function:- Cilia and flagella helps in locomotion.
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29.  Centrioles are paired barrel -shaped cell organelle
found in alI animal cells but absent in plant cells.
 Function:- They are involved in development of
spindle fibres.
 Regulate cell division of cells.
 They also form basal body of cilia and flagella.
CENTRIOLE
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30. Vacuoles
 Vacuoles are non-living membrane bound structures
of cytoplasm present in all eukaryotic cells.
 Functions:- Helps in the function of osmoregulation.
 Also helps in phagocytosis and pinocytosis.
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31. Microbodies
 Many membrane bound minute vesicles called
microbodies that contain various enzymes are
present in both plants and animal cells.
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32. Diagram of Eukaryotic cells:- (A)Plant
cell
(B)Animal cell
32

33. Difference between Plant cell and
Animal cell
Features Plant cell Animal cell
Cell shape Plant cell is large
and has a fixed
rectangular shape
Animal cell is small
and irregular or
round in shape
Cell wall Present Absent
Nucleus Present; nucleus lies
on one side of cell
Present; nucleus lies
in the centre of the
cell
Mitochondria Present in fewer
numbers
Present in large
numbers
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34. Features Plant cell Animal cell
Plastids Present Absent
Centrosome Absent Present
Vacuole One large central
vacuole is present
Many small vacuoles
are present
Lysosomes Present but very
rare
Present
Mode of nutrition Primarily autotrophic Heterotrophic
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35. Comparison of prokaryotic and
eukaryotic cell
Features Prokaryotic cell Eukaryotic cell
Type of cell Always unicellular Unicellular and
multicellular
Cell wall Usually present,
chemically complex in
nature.
Present in plant cell but
absent in animal cell
Cell size Cells are smaller in size Cells are larger in size
nucleus Absent, instead they
have a nucleoid region in
the cell
present
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36. 36
Features prokaryotic cell Eukaryotic cell
Ribosomes Present, 70S type
(Subunits 50S & 30S)
Present, 80S type
(subunits 60S & 40S)
DNA arrangement Circular Linear
Mitochondria Absent Present
Plasmids Present Very rarely found in
eukaryotic cells
Centriols Absent Present in animal cells
Flagella Consists of a single fibril Consist of two central
and nine peripheral
(9+2) fibrils

37. Features Prokaryoti c cell Eukaryotic cell
Cell division Amitosis and binary
fission
Through mitosis and
meiosis
Reproduction Asexual both asexual and
sexual
Respiration Takes place on
plasma membrane
Takes place inside
the mitochondria
DNA Never associated
with histone protein
Always associated
with histone protein
Golgi body Absent Present
Lysosome Absent Present
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38. Features Prokaryotic cell Eukaryotic cell
Endoplasmic
reticulum
Absent Present
Nucleolus Absent Present
Cytoplasm Present, but cell
organelles absent
Present, containing
cell organelles
Example Bacteria and
archaebacteria
Plant cells and
animal cells
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39. Similarities between Prokaryotic
and Eukaryotic cell
 Both types of cells have plasma membrane of similar
construction.
 Both types of cells have genetic information encoded in DNA
using identical genetic code.
 Both types of cells have similar mechanism for transcription
and translation of genetic information, including similar
ribosomes.
 Similar mechanism for synthesizing and inserting membrane
protein.
 Similar apparatus for conservation of chemical energy as ATP
(located in the plasma membrane of prokaryotes and the
mitochondrial membrane of eukaryotes).
 Similar mechanism of photosynthesis. 39

40. REFERENCES
 Biology textbook of Class IX (N.C.E.R.T.)
 Cell and Molecular Biology- Concept and
experiment by Gerald Karp (6th Edition)
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41. THANKYOU
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