The document discusses the key components and structures of plant and animal cells. It begins by explaining how Robert Hooke first observed cells in cork in 1665 under a microscope. It then describes the basic components of cells, including the cell membrane, cytoplasm, organelles like the nucleus, mitochondria, chloroplasts, and vacuoles. The functions of these various organelles are outlined. The document concludes with an overview comparing the main differences between typical plant and animal cells.

1. A TOUR OF THE CELL
PRESENTATION BY: RAJAT KUMAR
IX-A

2. ROBERT HOOKEROBERT HOOKE
Cells were first
discovered by Robert
Hooke, in1665. He
observed a thin slice
of cork under his self
designed
microscope.This slice
of cork resembled the
structure of the
honeycomb consisting

4. CORK COMES FROM THE BARK
OF THE TREE
HONEY COMB

6. 1)these structures look
similar to each other.
2) together they form a big
structure like an onion bulb.
3) the cells of an onion peel
will all look same ,
regardless of the size of the
onion.
4) these small structures
are the basic building units
of the onion bulb and are
called cells.

7. ORGANISMS THAT HAVE A SINGLE CELL.
AMOEBA CHLAMYDOM
ONAS

8.  ORGANISMS HAVING MORE THAN
ONE CELL TO PERFORM VARIOUS
FUNCTIONS.
ANIMALS PLANTSFUNGI

9. BONE CELL
OVUM
SPERM BLOOD CELL
NERVE CELL FAT CELL

10.  A cell is the smallest unit that is capable
of performing life functions.

11.  The shape and size of cells are related to
the specific function they perform.
 Each living cell has the capacity to perform
certain basic functions.
 Cell contains a specific component called
organelles.
 Each kind of cell organelle performs a
special function.
 All cells are found to have the same
organelles , irrespective of their function
and which organism they are found in.

12. > The shape and size of the cells
depend upon the function they
perform. In a human body, each
organ performs a specific
function, hence the cells of
different organs have different
shapes and sizes.

13.  It is the outermost
covering of the cell that
separates the contents of
the cell from the external
environment.
 Allows the entry and exit
of materials in and out of
the cell.It also prevents the
movement of some other
material and is therefore
called a selectively
permeable membrane.
 The plasma membrane is
flexible and is made up of

14.  gaseous exchange takes place froma
region of higherconcentration to a
region of low concentration.

15. the movement of waterfroma region of high
waterconcentration through a semi-
permeable membrane to a region of low water
concentration.

16. Diffusio n Osmo sis
1)It can occur in
any medium.
2)It does not
require a semi-
permeable
membrane.
1)It occurs only in a
liquid medium.
2)It requires a semi-
permeable
membrane.

17. Hypotonic solution
Hypotonic solution is the solution surrounding
the cell which has higher water concentration
than that in the cell.
Water molecules are free to pass across the
cell membrane in both directions, but more
water will come into the cell than will leave. The
net result is that the water enters the cell and

18. When the medium surrounding a cell
has the same concentration of water as
that in the cell it is said to be isotonic.
Water crosses the cell membrane in
both the directions, but the amount
going in is the same as the amount
going out, so there is no overall
movement of water. The cell will stay

19. When the mediumsurrounding a cell has
lowerconcentration of waterthan that
in the cell it is said to be hypertonic.
Watercrosses the membrane in both the
directions, but this time more water
leaves the cell than enters it. Therefore
the cell will shrink.

20. Plasmolysis is the
phenomenon by
which a plant cell
shrinks away from
the cell wall when
it loses water by
osmosis.

21. >Hard outer covering of thecell.
>Present outsidethecell
membrane.
>Cell wall iscomposed of
cellulose.
>Celluloseisacomplex
substanceand providesstructural
strength to plants.
>Cell wall ispresent in theplant
cell and helpstheplant to
withstand theenvironmental
changes.

22. >Hasadoublelayered covering called
nuclear membrane.
 Nuclear membranehasporeswhich
allow thetransfer of material from
insidethenucleusto itsoutside
(cytoplasm).
 Containschromosomeswhich are
visibleasrod-shaped structuresonly
when thecell isabout to divide.
Chromosomescontain information for
inheritanceof featuresfrom parentsto
thenext generation in theform of DNA
molecules. (Deoxyribo Nucleic Acid).

24.  Example : Viruses
 Viruses lack any membranes and hence
do not show any characteristics of life
until they enter a living body and use its
cell machinery to multiply.

25. • It isthefluid content
insidetheplasma
membrane.
• Containsspecialised cell
organelles.

26. 1) Endoplasmic reticulum
2) Golgi apparatus
3) Lysosomes
4) Mitochondria
5) Plastids
6) Vacuoles

27.  ER isalargenetwork of membranebound tubesand sheets.
 Extendsthroughout cytoplasm
 Two types- Rough Endoplasmic Reticulum (RER)
Smooth Endoplasmic Reticulum (SER)
 Servesaschannelsfor thetransport of materialsbetween various
regionsof thecytoplasm or between thecytoplasm and thenucleus.
 Functionsasacytoplasmic framework providing asurfacefor
biochemical activities.

28. First discovered by Camillo Golgi.
 It consist of asystem of membrane- bound vesiclesarranged
parallel to each other in stackscalled cisterns.
 Thematerial synthesised near theER ispackaged and
dispatched to varioustargetsinsideand outsidethecell through
theGolgi apparatus.
 Itsfunctionsincludestorage, modification and packaging of
productsin vesicles.
Involved in theformation of thelysosome.

30. >Wastedisposal system of thecell.
Keep thecell clean by digesting
any foreign material aswell asworn
out cell organelles.
 Contain powerful digestive
enzymescapableof breaking down
all organic material.
When thecell getsdamaged,
lysosomesmay break open and the
enzymesdigest their own cell. Thus
known assuicidebagsof acell.

31. Known asthepowerhouseof thecell.
 Theenergy required for variouschemical activitiesis
released by themitochondriain theform of ATPmolecules.
( Adenosinetriphosphate).
ATPisknown astheenergy currency of thecell.
 Mitochondriahavetwo membranecoverings.
 Outer membraneisvery porous.
Inner membraneisdeeply folded.
Mitochondriaareableto maketheir own proteins asthey
havetheir own DNA and ribosomes.

32.  Present in plant cells.
 Two types- 1) Chromoplasts(coloured)
2) Leucoplasts(colourless)
> Plastidscontaining green pigment chlorophyll arecalled
Chloroplasts.
 Leucoplastsstorematerialsasstarch, oilsand protein
granules.
 Plastidscontain membranelayersembedded in amaterial
called stroma.
 Hasasimilar structurelikethemitochondria.
 Havetheir own DNA and ribosomes.

34.  Storagesac for solid or liquid contents.
 Small size vacuolesarepresent in animals.
 Largein plants.
 In plant cells, vacuolesarefull of cell sap and provide
turgidity and rigidity to thecell.
 Vacuolesstoreamino acids, sugars, variousorganic acidsand
someproteins.
 InAmoeba, thefood vacuolecontainsthefood itemsthat the
Amoebahasconsumed.
 Vacuolesplay an important rolein expelling excesswater
and somewastesfrom thecell.

37. Overview of a plant cell

38. Animal cell Plant cell
Animal cells are generally small
in size.
Plants cells are usually larger
than animal cells.
Cell wall is absent. Cell wall is present.
Except the protozoan Euglena,
no animal cell possesses
plastids.
Plastids (chromoplasts and
leucoplasts) are present.
Vacuoles are smaller in size. Vacuoles are larger in size.