Specially for Science students. Understand cell completely with easy language. Easy language for students who are not good in English. Students who are in high school just read it with conscious mind and grab the points which will help in understanding cell easily as well as it will help you to score good in tests/exams. For students who are in universities colleges need to understand it completely by putting some efforts.

1. BY:- MANJOT SINGH

4. INTRODUCTION
• It is the Fundamental and Structural Unit of
Life.
• Self replicating structure.
• Some species are unicellular and some are
multicellular.
• Diameter : 2–120micro-meter.

5. ROBERT HOOK
• The first cell was observed
by Robert Hooke in 1665
from Slice of Cork.
• Robert hook discovered the
first dead cell.

6. Living Cell Discovery
• The first living cell was observed
by Anton van Leeuwenhoek.
• He is known as the father of
Microbiology.

8. Difference between Plant Cell and
Animal Cell
PLANT CELL ANIMAL CELL
• Cell wall is present. • Cell wall is absent.
• Chloroplast is present. • Chloroplast is absent.
• Large and permanent vacuole is
present.
• Small and temporary vacuole is
present.
• Centrosome is absent. • Centrosome is present.
• Food storage in form of starch. • Food storage is in the form of
glycogen.
• Nucleus in present near the cell
membrane.
• Nucleus is present the center of
the cell.
• They are autotrophs. • They are heterotrophs.

9. UNICELLULAR CELLS MULTICELLUAR CELLS
Single cell organisms Organisms with more than one
cell.
Eg: Monera, Protista Eg: Animals, Fungi, Plants

10. CELL THEORY
• It was proposed by Matthais Schleiden and
Theoder Schwann in 1839.
• All living things are made up cells.
• Cells are the smallest working unit of the living
things.
• All new cells take birth from cell division of
pre-existing cells.

11. TYPES OF CELLS
• There are many types of cell :-
i. Stem cell
ii. Bone cell
iii. Blood cell
iv. Muscle cell
v. Sperm cell
vi. Female egg cell
vii. Fat cell
viii.Nerve cell
• The main type of cell are :-
i. Prokaryotic Cell
ii. Eukaryotic Cell

12. Prokaryotic Cells
• They are the primitive cells.
• They possess small and shrink nucleus.
• The nucleus is present near the cell membrane.
• Membrane bounded cell organelles are absent.
• 70s ribosomes are present.
• DNA are double circular.
• Histone proteins in DNA are absent.
• Chromosomes are naked.
• Example: Monera and Protista.

13. Eukaryotic Cells
• They are true cell.
• The nucleus is large and round shape.
• The nucleus is present in the center of the cell.
• Membrane bounded cell organelles are present.
• 70s and 80s ribosomes are present.
• DNA are well developed.
• Histone protein in DNA are present.
• True chromosomes are present.
• Example: Plants, Fungi, Animals.

14. CONSTITUENTS
• Different substances that make a cell are
collectively called Protoplasm.
• Protoplasm is composed of :-
i. Water – 70-85% in a cell
ii. Carbohydrates – 1%
iii. Lipids – 2-3%
iv. Proteins – 10-20%
v. Electrolytes – Sodium(Na+), Potassium(K+),
Magnesium(Mg2+), Calcium(Ca2+),
Chloride(Cl-) and Bicarbonate(HCO3-)

15. SUBCELLULAR STRUCTURES
• Major Structures Present in a Cell are :-
i. Cell Boundaries
ii. Cytoplasm
iii. Cell Organelles
iv. Nucleus

16. CELL BOUNDARIES
Capsule Cell Wall
Cell
Membrane

17. CAPSULE
• It is present outside the cell wall.
• It is also called Slime layer.
• Capsule is made up of Polysaccharide.
• Eg:- Gram Positive Bacteria and Gram
Negative Bacteria

19. CELL WALL
• Cell wall was discovered by Robert Hook.
• Cell wall is dead, thick and hard.
• Functions:
i. Protection of the cell.
ii. Join two cell.
iii. Maintaining the shape.

21. Cell Membrane
• Cell membrane is living and thin layer.
• It is made up of Phospholipid(55%) and
Protein(45%).
• Thin pliable elastic outermost structure which
envelops the cell.
• It consists of Bilipid Layer
with embedded proteins
that are :-
i. Integral Proteins
ii. Peripheral Proteins

24. Function of Cell Membrane
• Protection : Forms outermost boundary of the cell
organelles .
• Digestive: Takes food in and excrete waste products.
• Selectively Permeable:
i. Non-Polar Molecules: Gases (like O2,CO2,N2), Lipids,
Steroid Hormones, Alcohols can dissolve in the non-
polar regions of the membrane and move rapidly
across the membrane.
ii. Polar Molecules: H2O soluble ions, Glucose, Urea,
etc. have much lower solubility. Therefore Penetrate
the membrane much more slowly.

25. • Chemical and Physical Properties: This
controls the free passage of ions in and out of
the cell. This property helps in maintaining
components in Intracellular fluid(ICF) and
Extracellular Fluid(ECF).
• Joint: Links adjacent cells together by
junctional complexes to form tissues.
• Insulating Properties: It acts as dielectric
material of a charged condenser, thus cell
membrane have very high insulating value.

26. CYTOPLASM
• Thick, gel-like semitransparent fluid that is
found in both plant and animal cell.
• The constituent parts of cytoplasm are
cytosol, cell organelles and cytoplasmic
inclusions.
• Bounded by the plasma membrane and
contains many organelles in a eukaryotic cell
(cell containing membrane bounded nucleus).

28. CELL ORGANELLES
• There are eight main cell organs:
i. Endoplasmic Reticulum
ii. Golgi Body
iii. Ribosomes
iv. Lysosomes
v. Mitochondria
vi. Centrosome
vii. Vacuole
viii.Plastid

29. ENDOPLASMIC RETICULUM
• Name and discovered by Keith R. Porter and
Thomson in 1945.
• Absent in prokaryotic cell.
• Present in eukaryotic cell.
• Functions of Endoplasmic Reticulum:-
i. Cell skeletal.
ii. Protein and Lipid synthesis.
iii. Detoxification in Liver.
iv. Lysosome and golgi body formation.

30. Types of Endoplasmic Reticulum
Rough ER- It is present near the nucleus membrane and
ribosomes are present.
Smooth ER- It is present near the cell membrane and ribosomes
are absent.

32. GOLGI BODY
• It was discovered by Camillo Golgi in 1895.
• It has some more names:-
i. Golgi apparatus
ii. Golgi complex
iii. Idiosomes
iv. Dicteosomes (In plants)

33. • Parts of Golgi Body:-
1. Cisterni - It is bag like structure in which
branches are absent.
2. Tubes - In this branches are present and its
function is to receiving the substances.
3. Vesicles - Its function is packing the
substances.

34. STRUCTURE

35. • Function of Golgi Body:-
i. Export and import of substances.
• Receives substance from Endoplasmic
Reticulum.
• Packing of substances in vesicles.
• Export or import of substance from cisterni.
ii. Formation of Lysosomes.
iii. Synthesis of Polysaccharide.

36. LYSOSOME
• It was name and discovered by Christian de Duve
in 1955.
• It is also known as Suicidal Bag because of
Phekosytosis.
• It is Polymorphic Structure.
• Function:-
i. Extra cellular digestion.
Eg: Ovam membrane is digested by sperm lysosome.
ii. Intra cellular digestion.
iii. External particle or bacteria digestion.

37. • Structure of Lysosome:-

38. RIBOSOME
• It was discovered by George E.Palade in 1955.
• It is membrane less organ.
• It is present in prokaryotic and eukaryotic cell.
• It is smallest organelle (150A-250A).
• Ribosome is made up of RRNA+Protein= Ribo-
Nuclic Protein.
• It is also known as Cell engine.
• It’s main function is Protein Synthesis.

39. Types of
Ribosome
70s
It is mainly present in
prokaryotic cells and sometimes
in eukaryotic cells also.
It is made up with 50s and 30s.
80s
It is present in Eukaryotic Cells
only.
It is made up of 60s and 40s.
s= Sediment Unit.
Chloroplast and mitochondria have 70s ribosome, that’s why they
are called organ with organ.

40. • Structure of Ribosomes:-

41. MITOCHONADRIA
• First discovered by Albert von Kolliker in 1857.
• Discovered by Altman and Fleming.
• Named by Carl Benda.
• It also known as Power House of the cell because
it makes energy in form of ATP.
• Life span is of 3-10 days.
• It is double membrane organ .
• Anew mitochondria is made by old dead
mitochondria.

42. • Structure of Mitochondria:-

43. CENTROSOME
• Centrosome is the membrane bound organelle
present near the nucleus.
• It is consists of two structures known as Centrioles.
• Centrioles are hollow, cylindrical structures made
up of microtubules.
• Centrioles are arranged ate right angles to each
other.
• Functions:-
i. Form spindle fibers which help in the movement
of chromosomes during cell division.
ii. Help in formation of cilia and flagella.

44. • Structure of Centrosome:-

45. VACUOLES
• Single membrane sac filled with liquid or sap (water,
sugar and ions).
• In animal cells, vacuoles are temporary, small and less
in number.
• In plant cells, vacuoles are large and more in numbers.
• May be contractile or non-contractile.
• Functions:-
i. Store various substances including waste products.
ii. Maintain osmotic pressure of the cell.
iii. Store food particles in amoeba cells.
iv. Provide turgidity and rigidity to plant cells.

46. • Structure of Vacuole:-

47. PLASTID
• Named by Heakel.
• Plastids are double membrane bound
organelles found inside plant sand some algae,
• They are responsible for activities related to
making and storing food.
• They often contain different types of pigments
that can change color of the cell.

49. Chromoplast
• Chromoplasts are
plastids that produce
and store pigments.
• They are responsible
for different colors
found in leaves,
fruits, flowers and
vegetables.

50. Leucolplasts
• Leucoplasts are
colorless plastids
that store foods.
• They are found in
storage organs
such as fruits,
tubers and seeds.

51. Chloroplasts
• Double membrane bound organelles found
mainly in plant cells.
• Usually spherical or discoidal in shape.
• Shows two distinct regions-grana and stroma.
• Grana are stacks of thylakoids(membrane bound,
flattened discs).
• Thylakoids contain chlorophyll molecules which
are responsible for photosynthesis.
• Stroma is colorless dense fluid.

52. • Functions:-
• Convert light energy
into chemical energy
in the form of food.
• Provide green color to
leaves, stems and
vegetables.

53. NUCLEUS
• Discovered by Robert Brown in 1831.
• It is dense spherical body located near the center of the
cell.
• Diameter varies from 10-25micrometer.
• Present in all the cells except Red Blood Cells and Sieve
Tube Cells.
• Well developed in plants and animals.
• Undeveloped in bacteria and blue-green
algae(cyanobacteria).
• Most of the cells are uninucleated.
• Few types of cells have more than one nucleus for example
Skeletal Muscle Cells.

55. • Nucleus has a double layered covering called
nuclear membrane.
• Nuclear membrane has pores of diameter about
80-100nm.
• Colorless dense sap present inside the nucleus
known as nucleoplasm.
• Nucleoplasm contains round shaped nucleolus
and network of chromatin fibers.
• Fibers are composed of DNA and histone protein.
• These fibers condense to form chromosomes
during cell division.

56. • Chromosomes contain stretches of DNA called
Genes.
• Genes transfer the hereditary information
from one generation to other generation.
• Function:-
• Control all the cell activities like metabolism ,
protein synthesis, growth and cell division.
• Nucleolus synthesizes RNA to constitute
ribosomes.
• Store hereditary information in genes.

57. Number of Nucleus in a Cell
i. Uninucleated
• Cell in which only one nucleus is present.
• Eg:- Eukaryotic cells
ii. Binucleated
• Cells in which two nucleus are present.
• Eg:- Paramecium
iii. Multinucleated
• Cells in which more than two nucleus are
present.
• Eg:- Endosperm

58. • Centriole: It is situated in close of nucleus and
serves to initiate the process of cell division. The
centrioles are present inside the apparatus called
centrosome.
• Granules: It is in the cytoplasm represent various
forms of stored secretions e.g. pigments,
hormones, digestive secretion, etc.
• Nucleoli: They are more clearly visualised in a
developing nucleus of the cell. These may take up
basic stains(Karyosomes) or acid
stains(Plasmosomes). These are rich in RNA