The document summarizes the structure and components of eukaryotic cells. It describes the three main cell structures - cell membrane, nucleus, and cytoplasm. It outlines the components of the nucleus including the nuclear envelope, chromosomes, and nucleoli. It also describes various cell organelles in the cytoplasm like the endoplasmic reticulum, Golgi apparatus, lysosomes, mitochondria, and ribosomes. Finally, it discusses the cytoskeleton and various surface projections of cells like cilia, flagella, and microvilli.

1. Structure
of
the cell

2. State the component parts of a eukaryotic cell
Describe the components of the nucleus
State the components of the cytoplasm
Describe the structure and functions of organelles
Describe the components & importance of the
cytoskeleton
Describe the surface projections of the cell; microvilli,
brush border, striate border, cilia & flagella
OBJECTIVES

3. Definition of Cell
A cell is the smallest unit that is
capable of performing life
functions.

4. Cell History
• Cells were discovered in 1665 by Robert Hooke.
Early studies of cells were conducted by
- Mathias Schleiden (1838)
- Theodor Schwann (1839)
• Schleiden and Schwann proposed the Cell Theory.

5. Cell Theory
• All living things are composed of one or more
cells.
• Cells are the smallest working units of all living
things.
• All cells come from preexisting cells through cell
division.

6. Examples of Cells
Amoeba Proteus
Plant Stem
Red Blood Cell
Nerve Cell
Bacteria

7. Prokaryotic
Cell Types
Eukaryotic
Unicellular Multicellular

8. 8
Eukaryotic Cell
Contain 3 basic cell structures:
– Cell Membrane
– Nucleus
– Cytoplasm -organelles
centrioles
cytoskeleton
inclusions

9. Representative Animal Cell

10. Plasma membrane / plasmalemma

11. 11
Eukaryotic Cell
Contain 3 basic cell structures:
– Cell Membrane
– Nucleus
– Cytoplasm -organelles
centrioles
cytoskeleton
inclusions

12.  Centre of the cellular activity
 Contains chromosomal DNA and the system for
RNA synthesis that allows DNA to be present as
specific proteins in the cytoplasm
 Stain with H&E shows a purplish blue color
 Varies in shape and size.
 May be flattened in cells containing fat or mucous.
 Some cells have more than one nucleus
(Osteoclasts, Liver cells, foreign body giant cells)
Nucleus

14.  Nuclear envelope
 Chromosomes
 Nucleoli
 Nuclear matrix
 Nucleoplasm
Nucleus - components

15. Nuclear
envelope

16. Chromosomes
Heterochromatin

17.  is tightly coiled, condensed and therefore darkly
stained, electron dense
 found at the periphery and scattered in the nucleus.
 metabolically inactive
 uncoiled, extended and hence not clearly stained
 electron translucent and found in open faced nuclei
 this type is metabolically active and is involved in
protein synthesis.
Chromosomes
Heterochromatin
Euchromatin

18. Nucleoli
Pars granulosa
Pars filamentosa
Pars amorphosa
N
u
c
l
e
o
l
e
n
e
m
a

19. Nuclear matrix & Nuclear sap

20. 20
Eukaryotic Cell
Contain 3 basic cell structures:
– Cell Membrane
– Nucleus
– Cytoplasm -organelles
centrioles
cytoskeleton
inclusions

21.  Organelles
Membrane bound structures important for the
metabolic functions of the cell.
Endoplasmic reticulum
Golgi apparatus
Lysosomes
Ribosomes
Mitochondria
Transport vesicles
Cytoplasm

22. Rough ER - “rough” because of associated with
ribosomes
- segregate proteins which are to be
exported from the cell
Smooth ER - lacks ribosomes
- synthesis of membrane lipids & steroid
hormones
- oxidation, conjugation & methylation
Endoplasmic Reticulum (ER)

24. Golgi apparatus

25. Golgi apparatus
collect, modify, package, and distribute molecules
synthesized at one location in the cell and utilized at
another location

26. Lysosomes

28. Ribosomes
 Ribosomes are RNA-protein complexes
composed of two subunits that join and
attach to messenger RNA.
 site of protein synthesis
 assembled in nucleoli

29. Ribosomes - Small electron dense particles
ribonucleic acid (60%) and
proteins (40%)
 Two classes of ribosomes
a) found in prokaryocytes and mitochondria
b) in eukaryotic cells
 Made up of major and minor subunits.
 They occur as granules or in a cluster held
together by a mRNA stranded.
Ribosomes

30. 30
Mitochondria

31.  Function : Involved in production and storage of
energy (Powerhouse of the cell)
 Enzymes : electron transport system of tissue
respiration and oxidative phosphorylation are
attached to cristae.
 Mitochondrial matrix is rich in proteins, DNA, RNA,
enzymes for krebs cycles and fatty acid oxidation
Mitochondria

32. 32
Mitochondria origin
Theory of Endosymbiosis

33.  Structures in the cytoplasm are classified into 3
groups
Cytoplasm
Organelles
Inclusions
Others
temporary components of the cell
Lipids
stored foods
Centrioles
Microtubules
microfilaments
Intermediate filaments

34. Centrioles

35. Centrioles

36.  associated with the organization of the mitotic
spindle during cell division.
 may migrate near the surface of the cell to give
rise to a basal body cilium
 concerned with the synthesis of:
microtubules
cilia
Centrioles

37. Cytoskeleton

38. Cytoskeleton

39.  Structures in the cytoplasm are classified into 3
groups
Cytoplasm
Organelles
Inclusions
Others
temporary components of the cell
Pigments, Lipids,
Carbohydrates, stored foods
Centrioles
Microtubules
microfilaments
Intermediate filaments

40. Projections from the cell surface

41. Surface projections from the cell
Cilia
Flagella
Microvilli

42. Cilia
centriole

43. Cilia

44. Surface projections from the cell
Cilia
Flagella
Microvilli

45. Flagella
 They are somewhat larger processes having the
same basic structure as cilia.
 Spermatozoon

46. Surface projections from the cell
Cilia
Flagella
Microvilli

47. Microvilli
 Finger-like projections from apical cell surface (0.1μm long)
 Structure
 outer covering of plasma membrane
 cyctoplasmic core with microfilaments which continuous
with actin filaments of the cell
 other transversely running filaments at the base of the
microvilli form the terminal web
 in turn anchored to the lateral wall of the cell at the
zonula adherens
 Numerous enzymes, & glycoproteins , concerned with
absorption are located in microvilli

48. Microvilli
 Microvilli arranged in a regular series - striate border
small intestine
 Microvilli arranged in a less regular - brush border
Gall bladder
 Highly folded surface extensive surface area for absorption
 a site for the attachment of digestive enzymes (small intestine )
 microfilaments in microvilli transport of the absorbed
material from the cell surface to the inside.

49. Classification of cell junctions
Occluding junctions (6)
tight junctions and septate junctions
Anchoring junctions
Actin filament attachment sites
Cell-cell (adherens junctions) (8)
Cell-matrix (focal adhesions)
Intermediate filament attachment sites
Cell-cell (desmosomes) (9)
Cell-matrix (hemi desmosomes) (10)
Communicating junctions
gap junctions (7)

50. SUMMERY

51. SUMMERY

52. REFFERENCES
 Burkit, H.G, young, B. (1993). Wheaters
functional histology. 4 th ed.,
london:Churchill livingstone
 Junqueira, L.C., Carneiro (1998). Basic
histology. 9 th ed., stamford: Appleton &
lange