Unlocking the Mysteries of the Cell: A Journey into the Building Blocks of Life Embark on an enlightening voyage into the intricate world of cells with our captivating SlideShare presentation. From the tiniest microorganisms to the complex structures within our bodies, delve into the fundamental units of life that shape our existence. In this visually engaging presentation, we explore the fascinating realms of cell biology, unraveling the mysteries of cellular structure, function, and diversity. Discover the inner workings of cells, from the powerhouse mitochondria to the information hub of the nucleus, and delve into the dynamic processes that sustain life. Featuring stunning visuals, insightful explanations, and intriguing facts, our presentation is designed to enlighten and inspire audiences of all backgrounds. Whether you're a seasoned biologist, a curious student, or simply intrigued by the wonders of life, join us on this immersive journey into the heart of the cell. Unlock the secrets of life itself and gain a deeper appreciation for the remarkable complexity and beauty of the cellular world. Don't miss out on this captivating exploration of "the cell" – the foundation of all living organisms.

1. MR. SAGAR PANDYA
ASSISTANT PROFESSOR
M.Sc. Nursing (Child Health Nursing)
Bhagyalaxmi College Of Nursing, Modasa (Guj.)
THE CELL

2. THE CELL
(The basic unit of life)
Engage: Cell History
Cytology- study of cells
1665 English Scientist
Robert Hooke
Used a microscope to
examine cork (plant)
 Hooke called what he
saw "Cells"

3. Cell History
 Robert Brown
◦ Discovered the nucleus in
1833.
 Matthias Schleiden
◦ German Botanist Matthias
Schleiden
◦ 1838
◦ ALL PLANTS "ARE
COMPOSED OF CELLS".
 Theodor Schwann
◦ Also in 1838,
◦ Discovered that animals
were made of cells

4.  Rudolf Virchow
◦ 1855, German Physician
◦ " THAT CELLS ONLY COME FROM
OTHER CELLS".
 His statement debunked
"Theory of Spontaneous
Generation"
Cell Theory
The COMBINED work of Schleiden, Schwann,
and Virchow make up the modern CELL
THEORY.

5. Principles of Cell Theory
 All living things are made of cells
 Smallest living unit of structure and
function of all organisms is the cell
 All cells arise from preexisting cells
(this principle discarded the idea of
spontaneous generation)

6. Cell Types
 Prokaryotic
 Eukaryotic

7. 7
Prokaryotes – The first Cells
 Cells that lack a nucleus or
membrane-bound organelles
 Includes bacteria
 Simplest type of cell
 Single, circular chromosome
 Nucleoid region (center) contains the
DNA
 Surrounded by cell membrane & cell
wall (peptidoglycan)
 Contain ribosomes (no membrane) in
their cytoplasm to make proteins

8. Prokaryotic Examples
ONLY BACTERIA

9.  EUKARYOTIC CELLS
Two Kinds:
Plant and
Animal

10. 10
Eukaryotes
 Cells that have a
nucleus and
membrane-bound
organelles.
 Includes protists, fungi,
plants, and animals.
 More complex type of
cells

11. 11
Eukaryotic Cell
Contain 3 basic cell
structures:
 Nucleus
 Cell Membrane
 Cytoplasm with
organelles

12. The Nucleus: Brain of Cell
 Bordered by a porous
membrane - nuclear
envelope.
 Double membrane
 Contains thin fibers of
DNA and protein called
Chromatin.
 A chromosome contains
thousands of hereditary
units called genes
 Rod Shaped
Chromosomes
 Contains a small round
nucleolus
 Produces ribosomal RNA
which makes ribosomes.

14. • Controls the normal activities of the cell.
• Usually the largest organelle.
• Genes control cell characteristics.
• Each cell has fixed number of
chromosomes that carry genes.
• Inside the nuclear membrane
present a fluid called neucleoplasm.

15. 15
Nuclear Envelope
 Double membrane
surrounding nucleus
 Also called nuclear
membrane
 Contains nuclear pores for
materials to enter & leave
nucleus
Nuclear
pores

16. 16
Inside the Nucleus -
The genetic material (DNA) is found
DNA is spread out
And appears as
CHROMATIN
in non-dividing cells
DNA is condensed &
wrapped around proteins
forming
as CHROMOSOMES
in dividing cells

17. 17
What Does DNA do?
DNA is the hereditary material of the cell
Genes that make up
the DNA molecule
code for different
proteins

19. Cell or Plasma Membrane
Outside
of cell
Inside
of cell
(cytoplasm)
Cell
membrane
Proteins
Protein
channel Lipid bilayer
Carbohydrate
chains
 Composed of double layer of
phospholipids and proteins
 Surrounds outside of all cells
 Controls what enters or leaves the cell
 Also called semipermiable membrane
19

20. 20
Phospholipids Layers
 Heads contain glycerol &
phosphate and are hydrophilic
(attract water)
 Tails are made of fatty acids
and are hydrophobic (repel
water)
 Make up a bilayer where tails
point inward toward each other
 Can move laterally to allow
small molecules (O2, CO2, & H2O
to enter)

21. 21
Cell Membrane Proteins
 Proteins help move large molecules
or aid in cell recognition
 Peripheral proteins are attached on
the surface (inner or outer)
 Integral proteins (transmembrane
proteins) are embedded completely
through the membrane

22. Structure of the Plasma Membrane

23. Fluid Mosaic Model
(1972 Singer & Nicholson)
 The Fluid Mosaic Model,
proposed by Jonathan
Singer and Garth Nicholson in 1972.
 Proteins embedded and
floating in a sea of
phospholipids
protein
Phospholipid
Bilayer

24. Membrane Functions
 Protection
 Communication
 Selectively allow substances
in
 Respond to environment
 Maintaining cell shape and
size
Proteins Functions
 Transport
 Receptors
 Enzymes
 Signal
Transducers
 Support

25. Copyright 2009 John Wiley & Sons, Inc.
Membrane Permeability
 The cell is either permeable or
impermeable to certain substances
 The lipid bilayer is permeable to oxygen,
carbon dioxide, water and steroids, but
impermeable to glucose
 Transmembrane proteins act as channels
and transporters to assist the entrance of
certain substances, for example, glucose
and ions

26. Passive vs. Active
Processes
 Passive processes - Substances
move across cell membranes without
the input of any energy (use the kinetic
energy of individual molecules or ions)
 Active processes - A cell uses energy,
primarily from the breakdown of ATP, to
move a substance across the
membrane, i.e., against a concentration
gradient

27. Cytoplasm
• Jelly-like substance enclosed by cell membrane
or present between the cell membrane and
nuclear membrane
• The cytoplasm of cell is gel-like matrix
composed of water, enzymes, nutrients, wastes,
gases and contains cell structures such as
ribosome, endoplasmic reticulum, mitochondria,
lysosome, nucleus etc.
• The components of cytoplasm are responsible
for cell growth, metabolism, elimination of waste
and replication (reproduction) of the cell.

28.  Two components
1.Cytosol
- Intracellular fluid, surrounds the
organelles
- The site of many chemical reactions
- Energy is usually released by these
reactions
- Reactions provide the building blocks for
cell maintenance, structure, function and

29. 2. Organelles
•Specialized structures within the cell
•Very small (Microscopic)
•Perform various functions for a cell
•Found in the cytoplasm
•May or may not be membrane-bound

30. Cytoskeleton
Network of protein filaments throughout the cytosol
 Provides structural support for the cell
 Helps in maintaining cell shape
 Also help move organelles around
 Made of proteins
 Three types according to increasing size:
1.Microfilaments,
2.Intermediate filaments, and
3.Microtubules.

32. •Microfilaments
Microfilaments are threadlike & made of ACTIN
protein
•Microtubules
-Microtubules are tubelike & made of TUBULIN
protein
-In many cells, microtubules grow out from a
centrosome near the nucleus.
•Intermediate filaments
Intermediate filaments are the fibrous protein
thicker filaments
Cell membrane
Ribosomes
Endoplasmic
reticulum
Mitochondrion
Microtubule
Microfilament

33. Endoplasmic Reticulum:
 Complex network of
transport channels.
 Network of hollow
membrane tubules
 Connects to nuclear
envelope & cell membrane
 Functions in Synthesis of
cell products & Transport
 Two types
Rough endoplasmic reticulum
Smooth endoplasmic
reticulum

34. Rough Endoplasmic Reticulum
 Ribosome's attached to surface
◦ Manufacture proteins
◦ Not all ribosome's attached to rough ER
 May modify proteins from ribosome

35. Smooth Endoplasmic Reticulum
• No attached ribosome's
• Functions in poison detoxification.
• Has enzymes that help build molecules
-Carbohydrates
-Lipids
 Makes membrane lipids (steroids)
 Regulates calcium (muscle cells)
 Destroys toxic substances (Liver)
Functions

36. 36

37. Ribosome:
 Found by Robinson
and Brown.
 First seen in plant cell.
 Small non-membrane
bound organelles.
 Made up from protein
or ribose nucleic acid.
 Contain two sub units
(large subunit or small
subunit)
 Site of protein
synthesis.
 “Protein factory” of the
cell
 Either free floating or
attached to the

38. Mitochondrion
(Plural = Mitochondria)
• Surrounded by a
double membrane.
• Has its own DNA or
mDNA.
• “Powerhouse” of the
cell.
• Generate cellular
energy (ATP).

39. •More active cells like muscle cells have
MORE mitochondria.
•Both plants & animal cells have mitochondria
Site of CELLULAR RESPIRATION (burning
glucose)
• Structures:
* Outer membrane
* Inner membrane (Cristae)
* Matrix
* Intermembrane space

41. Outer membrane –
• Outer most covering of mitochondria.
• Permeable to larger molecules.
Inner membrane –
• Folded inner membrane called CRISTAE
(increases surface area for more chemical
Reactions)
Matrix –
• The mitochondrial matrix is a viscous fluid that
contains hundreds of enzymes responsible for
various functions.
•It is enclosed inside the inner membrane of
mitochondrion.

42. • The matrix of mitochondrion contains mainly
soluble enzymes.
• The other components of this matrix are
ribosome's and DNA.
• The contents of mitochondrial matrix are
viscous in nature.
• This is unlike the cell cytoplasm that
incorporates contents in a liquid state.
• Out of the total protein content of
mitochondrion, 60-70% is present in the matrix.
Intermembrane space –
• Space between inner and outer membranes.

43. Interesting Fact ---
 Mitochondria
Come from
cytoplasm in the
EGG cell during
fertilization
Therefore …
 You inherit your
mitochondria
from your
mother!

44. Golgi Bodies / Golgi Apparatus
Golgi complex –
•Consists of 3-20 flattened, membranous sacs called
cisternae.
•Modify, sort, and package proteins for transport to
different destinations.
•Proteins are transported by various vesicles.

45. •Have a shipping side (cis face) & a receiving side
(trans face).
•Receive proteins made by ER.
•Transport vesicles with modified proteins pinch
off the ends.
• Materials are transported from rough ER to Golgi
body to cell membrane by VESICLES.
•Packaging and shipping station of the cell.
•Also known as “Post Office” of the cell.

46. Proteins in vesicle
membrane merge
with plasma
membrane
Proteins exported
from cell by exocytosis
Plasma
membrane
Transport vesicle
Ribosome
Entry face cisterna
Exit face cisterna
Medial cisterna
Synthesized
protein
Transport vesicle
(to lysosome)
Transfer vesicle
Rough ER
Transfer vesicle
Membrane
vesicle
Secretory
vesicle
9
8
7
6
5
4
3
2
1
4

48. Lysosomes
 Vesicles that form from
the Golgi complex,
contain powerful
digestive enzymes.
 Break down food,
bacteria, and worn out
cell parts for cells.
 Programmed for cell
death (APOPTOSIS).

49. •Recycling Center
•Recycle cellular debris
•Membrane bound organelle containing a
variety of enzymes.
•Internal pH is 5.
•Help digest food particles inside or out side
the cell.
•Main function is Phagocytosis.

50. Vesicle
-A small spherical sac formed by budding off from
a membrane.
Endocytosis
- Materials move into a cell in a vesicle formed
from the plasma membrane.
Three types:- *Receptor-mediated endocytosis
*Phagocytosis
*Bulk-phase endocytosis (Pinocytosis)
Exocytosis
-Vesicles fuse with the plasma membrane,
releasing their contents into the extracellular fluid.
Transcytosis
- A combination of endocytosis and exocytosis.

51. 1
Clathrin-coated
pit
Binding
Receptor
Receptor-LDL
complex
LDL particle Plasma
membrane
Invaginated plasma
membrane
1
Clathrin-coated
vesicle
Clathrin-coated
pit
Binding
Vesicle formation
Receptor
Receptor-LDL
complex
LDL particle Plasma
membrane
Invaginated plasma
membrane
2
1
Clathrin-coated
vesicle
Clathrin-coated
pit
Binding
Vesicle formation
Receptor
Receptor-LDL
complex
Uncoated vesicle
Uncoating
LDL particle Plasma
membrane
Invaginated plasma
membrane
2
3
1
Clathrin-coated
vesicle
Clathrin-coated
pit
Binding
Vesicle formation
Receptor
Receptor-LDL
complex
Uncoated vesicle
Degradation
in lysosome
Lysosome
Transport
vesicle
Transport
vesicle
Fusion with
endosome
Recycling
of receptors
to plasma
membrane
Uncoating
LDL particle Plasma
membrane
Invaginated plasma
membrane
Endosome
Digestive
enzymes
2
3
4
5
6
Receptor-
Mediated
Endocytosis

52. Phagocytosis

53. Bulk-phase Endocytosis

54. Centrosomes (Centrioles)
 Found only in animal cells.
 Paired structures near
nucleus.
 Made of bundle of
microtubules.
 Appear during cell division
forming mitotic spindle.
 Help to pull chromosome
pairs apart to opposite
ends of the cell.
 Role in building cilia and
flagella.

55. •Fluid or Air filled
sacks for storage.
•Small or absent in
animal cells.
•Plant cells have a
large Central Vacuole.
•More common in
plant cell than animal
cell.
Vacuoles

56. Cilia & Flagella
•Function in moving cells,
in moving fluids, or in
small particles across the
cell surface (Provide
motility).
•Cilia are shorter and more
numerous on cells.
•Flagella are longer and
fewer (usually 1-3) on cells.
•Bundles of microtubules with
plasma membrane.
•Basal bodies like
centrioles.

58. Ciliated Epithelium

59. Flagellum