Cell biology studies the fundamental unit of life, the cell. There are two main types of cells - prokaryotic cells, which lack organelles and a nucleus, and eukaryotic cells, which have organelles and a nucleus enclosed in a membrane. The cell theory states that cells are the basic unit of life, all living things are made of cells, and new cells are produced from existing cells. Cells have several organelles that allow them to carry out functions necessary for life.

2. The key to
every biological
problem must
finally be
sought in the
cell, for every
living organism
is, or at some
time has been,
a cell. E.B.
Wilson, 1925
Why Study
Cell Biology?

3. CELL AS UNIT OF LIFE
 Fundamental or basic unit of life
 10 to 100 micrometers (μm) and
1 to 10 μm in diameter
 Robert Hooke (1665) - Latin word
“cellulae” meaning small rooms
 Anton van Leeuwenhoek (Dutch)
first to observe living cells
“animacules”
 In year 1838, Matthias Schleiden
(German) stated that all plants
“are aggregates of fully
individualized, independent,
separate beings, namely the
cells themselves.”

5. Cells are Us

6. Cilia on a protozoan Sperm meets egg
Cells are Us

7. A person contains about 100
trillion cells. That’s
100,000,000,000,000 or 1 x 1014
cells.
There are about 200 different
cell types in mammals (one of
us).
Cells are tiny, measuring on
average about 0.002 cm (20
um) across. That’s about 1250
cells, “shoulder-to-shoulder”
per inch.
nerve cell
Red and
white
blood
cells
above
vessel-
forming
cells.
Cells are Us

8. CELL AS UNIT OF
LIFE
 A German physiologist named
Theodor Schwann (1839),
reported that all animal
tissues also consist of
individual cells.

9. Two Fundamentally Different Types of Cells
A prokaryotic cell
A eukaryotic cell

10. Us vs. Them -
Eukaryotes
and
Prokaryotes

13. CELL THEORY
1. Cell is the fundamental unit
of life.
2. All living things are
composed of cells.
3. Cells arise from pre- existing
cells.

14. MODERN CELL
THEORY
1. Cells are the smallest living
things, the basic units of
organization of all organisms.
2. All organisms are composed of
one or more cells, and the life
processes of metabolism and
heredity occur within these
cells.
3. Cells arise only by division of a
previously existing cell.

18. The Cell Theory
All organisms are composed of one or more cells.
Cells are the smallest living
things.
All organisms living today are
descendents of an ancestral cell.
Cells arise only by division of previously existing cells.
The cell theory (proposed independently
in 1838 and 1839) is a cornerstone of
biology.
Schleiden
Schwann

19. DEVELOPMENT OF CELL
THEORY

20. ROBERT HOOKE
Nationality: English
Year: 1635 - 1703
Study/ Contribution:
 First to use microscope
 Responsible for the beginnings of
cytology

22. ANTON VAN
LEEUWENHOEK
Nationality: Dutch
Year: 1632 - 1723
Study/ Contribution:
 Discovered bacteria in rainwater
 Studied the structure of plant and
animal cells

24. JEAN BAPTISTE
PIERRE ANTOINE DE
MONET
Nationality: French
Year: 1744 - 1829
Study/ Contribution:
 Proposed that cells are filled with
fluids

25. FRANCESCO REDI &
LAZZARO SPALLANZANI
Nationality: Italian
Year: 1627 – 1697; 1729 -
1799
Study/ Contribution:
 discovered the
Spontaneous Generation
Theory

27. HENRI DUTROCHET
Nationality: French
Year: 1776 - 1847
Study/ Contribution:
 Proposed that cell is the fundamental
unit of living organism
 Proposed that all living things are
made up of cells

28. ROBERT BROWN
Nationality: Scottish
Year: 1773 - 1858
Study/ Contribution:
 Discovered the presence of nuclei
within cells
 Describe nucleus as small dense,
round body inside the cell

29. FELIX DUJARDIN
Nationality: French
Year: 1801 - 1860
Study/ Contribution:
 Noted that all living things contain a
thick jelly fluid called sarcode
 Recognized that one-celled
organisms are in existence

30. MATTHIAS SCHLEIDEN &
THEODORE SCHWANN
Nationality: German
Year: 1804 – 1881; 1810 -
1882
Study/ Contribution:
 Plants and animals are
made – up of cells

31. JOHANNES PURKINJE
Nationality: Czechoslovakian
Year: 1787 - 1869
Study/ Contribution:
 Coined the term “protoplasm”
 Described as jelly – like material that
fills the cell

32. MAX SCHULTZE
Nationality: German
Year: 1825 - 1874
Study/ Contribution:
 Used the term protoplasm to show
that this material is found in all
organism
 Protoplasm as the physical basis of
life

33. RUDOLF VIRCHOW
Nationality: German
Year: 1821 - 1902
Study/ Contribution:
 Found that cells divide to form new
cells
 Cells came from pre- existing cells
 Formulated the cell theory

34. LOUISE PASTEUR
Nationality: French
Year: 1882 - 1895
Study/ Contribution:
 Supplied the proof for Virchow’s
theory of biogenesis

36. JAMES WATSON &
FRANCIS CRICK
Nationality: American
British
Year: 1928 - ____; 1916 -
2004
Study/ Contribution:
 Built model for the
structure of DNA

37. CELL: ITS PARTS &
FUNCTIONS

38. PROKARYOTIC CELLS

39. EUKARYOTIC CELLS

40. NUCLEUS
 The largest and most easily
seen organelle
 Latin, “kernel” or “nut”
 contains most of the genes in
the
eukaryotic cell.
 controls or regulates all
chemical reactions within the
cell.

41. PARTS OF NUCLEUS
 Nuclear envelope – two (2)
phospholipid bilayer membranes
 Nuclear pores – form 50 to 80 nm
apart
 Nucleolus – region where intensive
synthesis of ribosomal RNA
 Nuclear lumina - inner surface of
the nuclear envelope is covered
with a network of fibers

42. NUCLEUS

43. The Nucleus Think of the nucleus as the cell’s
control center.
Two meters of
human DNA fits
into a nucleus
that’s 0.000005
meters across.

44. NUCLEAR PORES &
LUMINA

45. ENDOMEMBRANE
SYSTEM
 “endo” meaning within or internal
 group of membranes and organelles in eukaryotic
cells that works together to modify, package, and
transport lipids and proteins.
 nuclear envelope, the endoplasmic reticulum, the
Golgi apparatus, lysosomes, various kinds of vesicles
and vacuoles, and the plasma membrane.

46. ENDOPLASMIC
RETICULUM (ER)
 largest of the internal membranes
 endoplasmic means “within the
cytoplasm,” and reticulum is Latin
for “little net.”
 Extensive network of membranes
that it accounts for more than half
the total membrane in many
eukaryotic cells.
 Rough ER & Smooth ER

47. ENDOPLASMIC
RETICULUM (ER)
 In rough ER , newly synthesized
proteins can be modified by the
addition of short-chain
carbohydrates to form
glycoproteins.
 In the case of smooth ER, synthesis
of lipids, metabolism of
carbohydrates, detoxification of
drugs and poisons, and storage of
calcium ions. E.g. synthesis of
lipids, including oils, steroids, and
new membrane phospholipids.

48. Ribosomes and the Endoplasmic Reticulum

49. The Rough Endoplasmic Reticulum
Protein movement
(trafficking)
Protein synthesis
(about half the
cell’s proteins are
made here).
Protein
“proofreading”
Functions:

50. GOLGI
APPARATUS/COMPLE
X
 warehouse for receiving,
sorting, shipping, and even
some manufacturing.
 Named after an Italian
physician Camillo Golgi
 Latin cisternae meaning
“collecting vessels”

51. GOLGI
APPARATUS/COMPLE
X
 The two sides of a Golgi stack are
referred to as the cis face and the
trans face; these act, respectively, as
the receiving and shipping
departments of the Golgi apparatus.
The term cis means “on the same
side,” and the cis face is usually
located near the ER.
 The trans face (“on the opposite
side”) gives rise to vesicles that pinch
off and travel to other sites

52. LYSOSOMES
 a membranous sac of
hydrolytic enzymes that
many eukaryotic cells use to
digest (hydrolyze)
macromolecules.

53. LYSOSOMES
 a process called
phagocytosis (from the
phagein, to eat, and kytos,
vessel, referring here to the
cell). The food vacuole
formed in this way then fuses
with a lysosome, whose
enzymes digest the food

54. LYSOSOMES
 Lysosomes also use their
hydrolytic enzymes to recycle
the cell’s own organic
material, a process called
autophagy.

56. The Lysosome
Cell suicide (suicide is
bad for cells, but good for
us!)
Recycling cellular
components
Functions:
Digesting food or cellular
invaders
(The lysosome is not found
in plant cells)

57. VACUOLES
 large vesicles derived from the
endoplasmic reticulum and Golgi
apparatus.
 Food vacuoles, formed by
phagocytosis
 contractile vacuoles that pump
excess water out of the cell,
thereby maintaining a suitable
concentration of ions and
molecules inside the cell.

58. VACUOLES
 In plants, central vacuole is the
plant cell’s main repository of
inorganic ions, including potassium
and chloride.
 plays a major role in the growth of
plant cells, which enlarge as the
vacuole absorbs water, enabling
the cell to become larger with a
minimal investment in new
cytoplasm

59. PEROXISOMES
 Eukaryotic cells contain a variety
of enzyme-bearing, membrane
enclosed vesicles called
microbodies.
 Peroxisomes get their name
from the hydrogen peroxide
produced as a by-product of the
activities of oxidative enzymes.

60. MITOCHONDRIA &
CHLOROPLAST
 both surrounded by a
double membrane,
and both contain
their own DNA and
protein synthesis
machinery.
 both involved in
energy metabolism

61. ENDOSYMBIONT THEORY
 states that an early ancestor of
eukaryotic cells (a host cell)
engulfed an oxygen using
nonphotosynthetic prokaryotic
cell. Eventually, the engulfed cell
formed a relationship with the
host cell in which it was
enclosed, becoming an
endosymbiont (a cell living
within another cell).

63. MITOCHONDRIA
 found in nearly all eukaryotic
cells, including those of
plants, animals, fungi, and
most protists.
 Powerhouse of the cell
 range of 1–10 μm long
 Cristae
 Mitochondrial matrix

64. The Mitochondrion
Think of the mitochondrion as the
powerhouse of the cell.
Both plant and animal cells
contain many mitochondria.
(Mitochondria is the
plural of mitochondrion)

65. The Mitochondrion
A class of
diseases that
causes muscle
weakness and
neurological
disorders are
due to
malfunctioning
mitochondria.
Worn out mitochondria may be an important factor in aging.

66. Mitochondrial Diseases

67. Mitochondria and Health

68. CHLOROPLAST
 contain the photosynthetic
pigment chlorophyll that gives
most plants their green color.
 closed compartments of stacked
membranes called grana.
 each granum may contain from a
few to several dozen disk-shaped
structures called thylakoids

69. CYTOSKELETON
 a network of fibers extending
throughout the cytoplasm.
 Network of protein fibers that
supports the shape of the cell
and anchors organelles to
fixed locations.
 mechanical support to the
cell and maintain its shape.

70. CYTOSKELETON
 (1) actin filaments,
sometimes called
microfilaments; (2)
microtubules; and (3)
intermediate filaments.

72. The name is misleading.
The cytoskeleton is the
skeleton of the cell, but it’s
also like the muscular
system, able to change
the shape of cells in a
flash.
The Cytoskeleton
An animal cell cytoskeleton

73. A micrograph
showing
cytoskeleton (red),
ribosomes (green),
and membrane
(blue)
It’s Crowded In There

74. CENTRIOLES
 barrel-shaped organelles
found in the cells of
animals and most protists.
They occur in pairs, usually
located at right angles to
each other near the nuclear
membranes.

75. CENTROSOME AND
CENTRIOLES
 In animal cells, microtubules
grow out from a centrosome,
a region that is often located
near the nucleus.
 Within the centrosome is a
pair of centrioles, each
composed of nine sets of
triplet microtubules arranged
in a ring.

76. FLAGELLA & CILIA
 Some eukaryotic cells have
flagella (flagellum,150µ) and
cilia (cilium), cellularextensions
that contain microtubules (5-
10µ in length)
 consisting of a circle of nine
microtubule pairs surrounding
two central microtubules. This
arrangement is referred to as the
9 + 2 structure.

79. PLASMA MEMBRANE
 Or cell membrane
 Outermost layer of the cell
 Regulates the entrance and
exit of substances in the
cell.

80. CELL WALL
 Outermost layer of the
plant cell that contain
cellulose
 Support of the plant cell

81. CYTOPLASM
 cytosol
 Jelly-like substance inside
the cell
 Life processes occur

82. It’s Crowded In There
An artist’s conception of the cytoplasm - the region
of a cell that’s not in the nucleus or within an
organelle.

83. Cellular Anatomy
We’ll start by seeing what role these parts
play in making and moving proteins.

84. Animal and Plant Cells Have More
Similarities Than Differences

85. Cells In a Leaf

86. The Chloroplast
Think of the chloroplast as the solar panel of the plant cell.
Only plants have chloroplasts, but animals reap the benefits too.

87. Two Other Unique Features of Plant Cells
The central
vacuole
may occupy
90% of a
plant cell.

88. A Consequence of Cell Walls – the
Great Strength of Woody Plants

89. Cystic Fibrosis
Click here to see the article.

90. Many Diseases are Caused by Lysosome Malfunction

91. ½ CROSSWISE
Explain the modern cell theory. (10 points
each)
1. Cells are the smallest living things, the
basic units of organization of all
organisms.
2. All organisms are composed of one or
more cells, and the life processes of
metabolism and heredity occur within
these cells.
3. Cells arise only by division of a

92. ASSIGNMENT
Differentiate theory, principle and
universal law. (20 points)

93. REFERENCES
 Cadiz, A., Macasil, T., Pascual, C., Sanchez, R., &
Villanoy, F. (2017). General Biology 1: For Senior High
School. Mindshapers Co., Inc.
 Johnson, G., Loson, J., Mason, K., Raven, P., & Singer, S.
(2017). Biology. Eleventh Edition. McGraw-Hill
Education.