1. THE PROTOPLAST

2. The Cell
 the basic unit of life
 came from the Latin word cella meaning
storeroom or chamber
 term first used by Robert Hooke in 1665
while observing cork cells

4. The Cell
 Composed of:
1. Protoplast – the site of cellular
metabolism
2. Cell wall-outermost part of a plant cell

5. THE PROTOPLAST
 Made up of:
 1. Nucleus
 2. Cytoplasm
 consists of a liquid, colloidal phase of the
protoplast (cytosol/hyaloplasm/cytoplasmic
ground substance)
 with membrane-bound organelles

6. THE PROTOPLAST
 2. Cytoplasm
 with membrane-bound organelles
 Bounded by double membranes
 Bounded by single membrane
 ribosomes
 endomembrane systems
 cytoskeleton

7. PLASMA MEMBRANE
(ectoplast/plasmalemma)
 Controls passage of various substances into
and out of the protoplast
 In transfer cells, are highly invaginated,
which facilitates transfer of materials
 It coordinates the synthesis and assembly
of cell wall microfibrils (cellulose)

8. BIOLOGICAL MEMBRANES
 Composition
1. Phospholipids
2. Proteins
3. Carbohydrates

10. BIOLOGICAL MEMBRANES
Membrane bilayer
Phospholipids
• re amphipathic
A
molecules with
hydrophobic nonpolar
hydrocarbon tails and
hydrophilic heads

11. BIOLOGICAL MEMBRANES
Membrane Protein
2 types:
 Integral proteins- integrated into the bilayer
• May have access to only one side of the membrane
• Span the entire bilayer and have access to both sides
of the membrane (transmembrane protein)
 Peripheral proteins- bound to the
hydrophilic surface of transmembrane
protein

12. BIOLOGICAL MEMBRANES
Membrane Protein
F
U
N
C
T
I
O
N
S
:

13. BIOLOGICAL MEMBRANES
 osette of enzymes mediate the synthesis of
R
cellulose microfibrils

14. PROTOPLAST
Composed of:
Nucleus
Cytoplasm

15. NUCLEUS

16. NUCLEUS
• nformation
I
center of the cell
• ontains the
C
bulk of the cell’s
DNA
• ucleolus- site
N
of rRNA
synthesis

17. Cytoplasm
Cytosol

 Non-particulate portion; the liquid portion
 Contains proteins and other solutes
 Often assumes the physical properties of a gel
 Endomembrane system
 These membranes are either in direct contact
or connected via transfer of vesicles, sacs of
membrane.

18. Cytoplasm system
 Endomembrane
 System includes the nuclear envelope,
endoplasmic reticulum, Golgi apparatus,
vacuoles, and the plasma membrane.
 Cellular organelles
 Membrane-limited compartments
 Serve to compartmentalize the cells
 Cytoskeleton

19. ribosome

20. RIBOSOMES
Sites of protein synthesis
• mall spherical bodies about 15-20 nm in diameter
S
• onsist of protein and RNA
C
• ound along ER, cytoplasm, within mitochondria and plastids
F

23. ENDOMEMBRANE SYSTEM

24. Nuclear envelope
 with 2 membranes; with pores through
which molecules of RNA may leave the
nucleus and enter the cytoplasm

25. • ndoplasmic reticulum- continuous with nuclear
E
envelope
• types of ER
2
-smooth- tubular; site of lipid
synthesis
-rough - lamellar; site of
synthesis of membrane
proteins and proteins to
be secreted outside the
cell and into the vacuole

26. • olgi bodies (also called dyctyosomes, golgi stacks,
G
golgi apparatus or simply golgi)
-Consist of stacks of cisternae
-polarized structure
-receiving end from ER is cis face
-shipping side is the trans face
-finishes, sorts and ships cell products

27. VACUOLE
• nveloped by tonoplast/vacuolar membrane
E
• ontains a variety of inorganic ions,organic acids, sugars,
C
enzymes and secondary metabolic products including
pigments
• lays a role in maintaining water balance of cells; active
p
cytosol
absorption of ions result in increase in turgor
pressure in the cell and its expansion
and growth
• omparable to lysosomes
C
of animal cells
Cell wall
chloroplast

28. Plasma Membrane

29. Cellular organelles and
cytoskeleton

30. MITOCHONDRIA
• ites of respiration and
S
• nveloped by 2
E
• nner membrane is
I invaginated (cr
• nzymes for ATP production
E
 itochondrial matrix,a
m
fluid- filled space with DNA,

31. PLASTIDS
• riginate from proplastid pigments
O
Types:
Chloroplastids
• ontain photosynthetic
C
pigments
• ite of photosynthesis
S
Chromoplastids
• ontain carotenoid pigments
C
• ften so concentrated that they form crystalline deposits
O

32. PLASTIDS
Leucoplastids
• olorless plastids
C
• ypes:
T
1. Amyloplastids
store starch
2. Elaioplastids
store fats
3. roteinoplasts- store
p
proteins

33. PLASTID TYPES ARE INTERCONVERTIBLE

35. -etioplast is a plastid that develops in the absence of light; no
chloroplast, no chlorophyll; characterized by prolamellar bodies
composed of tubular membranes which comprise a
paracrystalline lattice

36. MICROBODIES
• ounded by a single membrane
B
• eroxisomes-
P
-major site of O2 consumption; uses O2 in
oxidation reactions that convert harmful
metabolic by-products into nontoxic
substances such as water
-break down fats
-participate in photorespiration; enzymes in
peroxisomes help minimize the loss
organic products due to photorespiration.

37. Peroxisome

38. Glyoxysomes- contain enzymes for the conversion of
fats to carbohydrates during seed germination
Cytoskeleton
 s a network of fibers
i
extending throughout the cy
 t provides mechanical
I
support and maintains
 t provides anchorage for
I
many organelles
and cytosolic enzymes.

39. CYTOSKELETON
 lays a major role in cell motility.
p
-This involves limited movements of parts of the cell
(streaming cytoplasm, vesicle and organelle
movement).
-The cytoskeleton interacts with motor proteins.
-Three main types of fibers
in the cytoskeleton:
• icrotubules
m
• icrofilaments
m
• intermediate filaments.

40. MICROTUBULES
 pprox 25 nm diameter
A
 omposed of 13 spherical protein subunits (dimers of α
C
and ß tubulin)
 omprise the spindle fibers in dividing cells that move
C
chromosomes during cell division.

41. MICROTUBULES
 unction as tracks that guide motor proteins carrying
f
organelles to their destination.
 esists compression to the cell.
r

42. CYTOSKELETON

43. MICROTUBULES
 phragmoplast, a complex of microtubules
that guides the orderly alignment of the
vesicles in the midzone

44. MICROTUBULES
 xert some control over orientation of microfibrils
e
because in regions of cell wall growth and cellulose
microfibril synthesis , microtubules below the
plasmalemma are routinely observed in an orientation
parallel to that of the newly synthesized microfibrils

46. ACTIN MICROFILAMENTS
 bout 7 nm in diameter
a
 omposed of globular actin.
C
 n actin microfilament consists of a twisted double
A
chain of actin subunits.
 elp maintain cell shape.
h

47. ACTIN MICROFILAMENTS
 Involved in cleavage furrow formation
 On the cytoplasmic side of the cleavage furrow a
contractile ring of actin microfilaments and the
motor protein myosin form.
 Contraction of the ring pinches the cell in two

48. ACTIN MICROFILAMENTS
 nvolved in cytoplasmic streaming
i
-This speeds the distribution of materials
within the cell.

49. Intermediate filaments
intermediate in size at 8 - 12 nanometers
 are specialized for bearing tension.
 re more permanent fixtures of the cytoskeleton than are
a
the other two classes.
 hey reinforce cell shape
t
 uclear side of the envelope is lined by the nuclear
n
lamina, a network of intermediate filaments that maintain
the shape of the nucleus.

50. ERGASTIC SUBSTRANCES- products of cell
metabolism
 torage products
S
 tarch in the form of starch grains
s
 roteins which form aleurone grains
p
 ils in elaioplasts or spherosomes (enveloped by
o
single membrane or may be lacking)
 axes- long-chain lipid compounds, that occur as
w
part of the protective coating (cuticle) on the
epidermis

52. LIPID BODIES OR OLEOSOMES
• unction: storage and transport of lipids
f

53. ERGASTIC SUBSTRANCES- products of cell
metabolism
Waste products
Crystals
-calcium oxalate crystals May be a form of stored calcium
-calcium carbonate crystals
Silica –common constituent of epidermal cell wall of grasses
-silica bodies – masses of silica which fill some epidermal cells
-provides protection from herbivory and mechanical strength

54. CRYSTALS

55. ERGASTIC SUBSTRANCES
 Tannins and tanniniferous substances are
phenolic by-products
 primary function – protective,their
astringency serving as a repellent to predators
 an impediment to the invasion of parasitic
organisms

56. The End