Fundamentals unit of life

1. BIOLOGY
Chapter- 5
Fundamental of life
Prerna Johari

2. TOPIC
CELLS: THE BASIC UNIT
OF LIFE

3. what is a cell ?
Cell is the basic unit of life.
All organisms are composed of cell
Some organisms are unicellular .eg: bacteria
And while some are multicellular . eg: human
Cell is the fundamental structural and
functional unit of all living organisms.
The study of cell is known as cell biology
or cytology.
It represents a distinct branch of biological
sciences which studies cell is referred to a
Cell Biology.

4. Organisms

5. The Discovery of the Cell
Robert Hooke-1665
Robert Hooke – first tosee and identify cork
“cells.”
Coined the word “cell”.
Looked at cork cells.

6. 1. All living organisms are made of cells.
2. Cells are the basic structural and functional
unit of all living organisms.
3. New cells arise from preexisting cells.

7. Historyof cell study
Robert hooke-1665
Coined the word “cell”.
Looked at cork cells.
Robert brown-1831
Discovered the “nucleus”.
TheodorSchwann- 1838
Cells are unit of biological structures.
Mattias Schleiden-1850
Cell are the fundamental basis of life.
Virchow-1858
All cells come from cells.

8. What is cell
made up of ?
The cell is filled with a semi-fluid
matrix called cytoplasm or
protoplasm which occupies the
major volume of cell. The
cytoplasm is the main site of
cellular activities in both plant
and animal cells. Various
chemical reactions take place in
the cytoplasm to keep the cell in
the ‘living state’.
.
 Cell is the basic structural and functional unit of living
organisms.
 A cell is made up of three main components-
1) Plasma membrane or cell membrane
2) Nucleus
3) Cytoplasm
 .

9. Define cell ?
 A cell is a mass of cytoplasm or protoplasm having a dense
membrane bound nucleus present inside it.
 This nucleus contains the chromosomes which in turn
contain the genetic material in form of DNA.

10. Types
of
cells
(based on
nuclear
organization)
Cell
Prokaryotic
cell
Eukaryotic
cell

11. Types of
cells
Types of cells-
Prokaryotic cell- The cell which lacks a well-organized or well –
defined nucleus and other membrane-bound organelles is
known as prokaryotic cell.
 The organisms which are composed of prokaryotic cells are
commonly called as prokaryotes.
 For example- Bacteria, mycoplasma, PPLO, etc.
Eukaryotic cell- The cell which possesses a well-organized
nucleus and other membrane-bound organelles is known as
eukaryotic cell.
 The organisms which are composed of eukaryotic cells are
commonly called as eukaryotes.
 For example- protists, fungi, plant and animal cells.

12. Difference
between
eukaryotic
cell and
prokaryotic
cell

13.  All eukaryotic cells are not identical. Plant and animal
cells are different.
 A plant cell contains a cell wall outside the cell membrane.
 An animal cell has cell membrane as the outermost
membrane of a cell.
 Plant cell possess cell walls, plastids, and a large central
vacuole. While, animal cells lacks cell wall, central vacuole
and plastids.

14. Shape of cells-
Theshapeandsize
ofcellsarerelatedto
thespecificfunction
theyperform.
 1.Smooth Muscle cell.
 2. Epithelial cells
 3. Nerve cell.
 4. Fat cell
 5. RBCs.
 7
. Spirogyra.
 8.Sperm and Ovum.
 9.Amoeba.
 10.Bacteria.

15. Plasma
membrane
or Cell
membrane
 Plasma membrane is the outermost covering of the
cell that separates the contents of the cell from its
environment.
 It is found in all cells.
 Plasma membrane is made up of two important
biomolecules- Lipids and proteins.

16. Functions of
Plasma
membrane
 Plasma membrane performs various important functions
in the cell.
 It is a selectively permeable membrane that allows or
permit the entry and exit of some materials in and out of
the cell.
 It also acts as a barrier and thus prevents the movement of
some other materials.
 It provides support and protection to the cell.
 Plasma membrane is flexible in nature.The flexibility of
the plasma membrane also help the cell to engulf in food
and other materials from its external environment. Such
process are called endocytosis.
 Amoeba acquires its food through such processes.

17. Movement
of
substances
across the
cell
 The movement of substances takes place into and
out of the cell.
 Plasma membrane plays an important role in
movement of substances into and out of the cell.
Process/ Methods-
 Diffusion -movementof particles from a region of high
concentration to low concentration.
 Osmosis-the diffusion of water through a selectively
permeable membrane.

18. Diffusion
Diffusion – movementof particles from an
region of highconcentration to low concentration.
Example- some substances like carbon dioxide or
oxygen can move across the cell membrane by a
process called diffusion.
Thus, diffusion plays an important role in gaseous
exchange between cells as well as the cell and its
external environment.

19. Osmosis
 Osmosis – the diffusion of water through a selectively
permeable membrane.
 Water also follows the law of diffusion. The movement of
water molecules through takes place through selectively
permeable membrane is called osmosis.
 Osmosis is the movement of water or water molecules from
a region of high water concentration to region of low water
concentration.
 The movement of water across the plasma membrane is
also affected by the amount of solute or substance dissolved
in water.
 Water will move in/out of a cell to equalize the
concentrations.

20. What is
solution?

21. Types of
solutions
Solvent
+Solute =
 There are three types of solutions-
 Hypotonic
 Isotonic
 Hypertonic

25. What will
happen if we
put an
animal cell or
a plant cell
into a
solution of
sugar or salt
in water ?

26. Activity on
Osmosis

27. CellWall

28. CELLWALL
1. a non living rigid structure .
2. Forms an outer covering for
plasma membrane inplant cells.
FUNCTION:
1) Determining Cell Shape.
2) Strength.
3) Controlling Turgor Pressure.
4) Passage of Substances.
5) Protection.

29. Cell
Organelles
Eukaryotic cell possess well-developed membrane
bound little structures within their cytoplasm. These
membrane bound little structures are called Cell
Organelles.
 Nucleus
 Endoplasmic Reticulum (ER)
 Golgi apparatus or Golgi complex
 Lysosome
 Mitochondria
 Plastids
 Vacuoles

31. Nucleus
 Every eukaryotic cell has a well-defined nucleus in
their cytoplasm.
 Robert Brown for the first time in 1833 discovered
a prominent body within the cell and termed it as
“nucleus”.
 The nucleus is a double wall structure that is remain
two surrounded by two nuclear membranes- outer
nuclear membrane and inner nuclear membrane.
 The nuclear membrane has pores called nuclear
pores which allow the transfer of substances or
materials from inside the nucleus to its outside in
the cytoplasm.
 The nucleus contains genetic material in the form
of DNA. Genes are located on DNA.
 Chromatin material – chromosomes

32.  Ultrastructure of the Nucleus :
 The nucleus contains three important parts,
namely,
i) nuclear membrane or nuclear envelope,
ii) nucleolus and
iii) chromatin material or chromosomes.

33. Functions of
Nucleus
 Nucleus play an important role in cell.
 It is controlling center of the cell.
 The nucleus contains genetic material in the form
of DNA. Genes are located on DNA.
 Chromatin material – chromosomes – hereditary
vehicles which passes genetic information from
parents to their offspring.
 It also plays a central role in cellular reproduction.

34. Endoplasmic
Reticulum
• Discovered by Porter and Thompson.
• I t is a complex membrane lined network of
flattened sac, tubles etc..
• runs through out cytoplasm of eukaryotic
cells.
• Consists of 30-40% of total endomembrane
system.
• Divides the intercellular space into
components-Luminal and extraluminal
 FUNCTIONS:
1. Mechanical support
2. Conduction of information
3. Intercellular transport
4. Localization of enzyme
5. Large surface area.

36. • Types of Endoplasmic reticulum-
i) Rough endoplasmic reticulum (RER).
ii) Smooth endoplasmic reticulum (SER).
 FUNCTION OF RER:
1. Protein for transport
2. Protein processing
 FUNCTION OF SER:
1. Storage.
2. Glycogenolysis.
3. Removal of toxic materials.

37. Endomembranesystem
contains only those
organelles whose
functions are
coordinated.
Itconsistsof:
Endoplasmic
reticulum(ER)
 Golgi complex
 lysosomes
 Vacuoles

38. Golgi
Apparatus

39. GOLGIAPPARATUS
• Is a cytoplasmic organelle of
smooth membrane sac.
• Dicovered by Camillo golgi,
• Found in eukaryotic cells (except
mammalian erythrocytes)
• Occur between nucleus and
exposed cell membrane.
• Surrounded by zone of cytoplasm
which is devioded of ribosomes,
mitochondria, etc...
FUNCTIONS:
Package materials. And important
for formation of glycoprotein.

40. LYSOSOMES
LYSOSOMES
• Membrane bound vesicular structure
• Formed by packaging of golgi appartus.
• Very rich in hydrolytic enzymes.
• Enzymes are capable for digesting
carbohydrate, protein, lipid, mucleic acid.
• Polpularly cal l ed as “suicidalbags”,

41. MITOCHONDRIA
• Thesearedouble –membrane bound, sausage –
shaped semi-autonomous organelles.
• The electron micrograph shows that the
boundarymembranes are separated by a fluid
filled space called outer compartment.
• The outer membrane is smooth but the inner
smooth projects in the form of many folds
called cristae into the matrix.
• The matrix is rich in enzymes, a circu lar DNA
• molecule and many small ribosomes.
• The inner membrane and the cristae bear a number
of particles, which havea spherical head– piece
(F1 subunit) and a stalk (F0 subunit) that is
embedded in the lipid of the membrane.
• The F0 – F1combination functions as ATP
synthetase.
• The main function of mitochondria is aerobic
respiration and ATP synthesis.
• “Power houses of cell”

42. Plastids PLASTIDS
• Plastids are double – membrane bound
organelles of different shapes, that are
found only in plant cells and contain
pigments and storage products.
Theycontainpigments,impartingcolorsand
storageproducts.

43. TypesofPlastids-
• Thesearethreetypes of p lastids, depending on their
colour and functions.
I) CHROMOPLASTS
• These are the coloured plastids containing mainly the
yellow, red and orangepigments (carotene and
xanthophylls).
(II) CHLOROPLASTS
• Thesearethe green plastids containing mainly
chlorophylls and very little of carotene and
xanthophylls.
• Chloroplasts may be lens – shaped, oval,spherical ,
discoid, ribbon-like or cup –shaped
• Each chloroplast has a double membrane covering,
enclosing the colourless matrix called stroma.

44.  (II) LEUCOPLASTS
 Colorlessplastids
 V
ariousshapesandsizes w
ithstorednutrients
 LEUCOPLASTcanbedivided
 into3:-
 Amy
loplasts– store carbohydrates
 Elaioplasts– storeoils andfats.
 Aleuroplasts– store proteins.

46. Plastids
Plastidscanbeclassifiedinto:
CHLOROPLAST
• Contains
chlorophylland
carotenoid
pigments.
• F
oundmainlyin
mesophyllof leaves
.
• T
hesearelens
shaped,oval
shaped,spherical,
discoidor even
ribbon-like
organelles.
CHROMOPLAST
• Containsfatsoluble
carotenoid
pigmentslike
carotene,
xanthophylls and
othersarepresent.
• F
oundinyellow
,
orange,red.
LEUCOPLAST
• Colorlessplastids
• V
ariousshapesand
sizes w
ithstored
nutrients
• LEUCOPLASTcanbe
divided
• into3:-
• Amyloplasts–
store
carbohydrates
• Elaioplasts–
storeoils and
fats.
• Aleuroplasts–
store proteins.

47. Vacuoles
In amoeba,
membrane-bound
sacs called
contractile vacuole
and in protista food
vacuole
 VACUOLES:
• In plant cells, Membrane bound space
found In cytoplasm.
• Bounded by single membranecalled tonoplast,

48. VACUOLE
VACUOLES:
• In amoeba, called contractile vacuole
and in proista food vacuole

50. ANIMAL CELL

51. PLANTCELL

52. Reference list
• Robayda, A. (2013). cell the unit of life. Available:
http://www.slideshare.net/AishaRobayda/cell-the-unit-of-life-1?qid=12bc18e8-e13c-
4232-9b02-cf1652411b05&v=qf1&b=&from_search=3 (Accessed 07 march 2014)
• ittah,E. (2013). Cell- The basic Structure of life.
Available: http://www.slideshare.net/ericittah/eric-ittah-canada-eric-
ittah?qid=12bc18e8-e13c-4232-9b02-cf1652411b05&v=qf1&b=&from_search=5
(accessed 07 march 2014)
• Baiju, V. (2011). Cell The unit of life. Available:
http://www.slideshare.net/VigneshBaiju/cell-the-unit-of-life-
10230437?qid=12bc18e8-e13c-4232-9b02-
cf1652411b05&v=qf1&b=&from_search=8 (accessed 07 march 2014)