Cell Biology_ Lec. (1).pdf cell biology introduction

cell biology

1. CELL BIOLOGY
Dr. Jihad El-Qassas (PhD)

2. Introduction of cell biology
▪Cell Biology:
•Branch of biological science which
deals with the study of structure,
function, molecular organization,
growth, reproduction and genetics
of the cells.
•Cell biology mainly concern with
study of structure of cell and
function of specialized cells.

3. Introduction of cell biology
▪History of cytology:
•The term cell – Robert Hooke (1635-1703) the mid 17
th
century to
describe the structure of cork.
•Anton van Leeuwenhoek (1632-1723): 1
st
recorded observations of
bacterial cells (termed “animalcules”) from pond water and tooth
scrapings.
•1830s: the importance of cells realized.
•1838: German botanist Matthias Schleiden (1804-1881) observed
that despite differences in tissue structure, all plants tissues were
made of cells.

4. Introduction of cell biology
▪History of cytology:
•The term cell – Robert Hooke (1635-1703) the mid 17
th
century to
describe the structure of cork.
Robert Hooke (the father of cytology)

5. Introduction of cell biology
▪History of cytology:
•The term cell – Robert Hooke (1635-1703) the mid 17
th
century to
describe the structure of cork.
Robert Hooke (the father of cytology)

6. Introduction of cell biology
▪History of cytology:
•The term cell – Robert Hooke (1635-1703) the mid 17
th
century to
describe the structure of cork.
•Anton van Leeuwenhoek (1632-1723): 1
st
recorded observations of
bacterial cells (termed “animalcules”) from pond water and tooth
scrapings.
•1830s: the importance of cells realized.
•1838: German botanist Matthias Schleiden (1804-1881) observed
that despite differences in tissue structure, all plants tissues were
made of cells.

7. Introduction of cell biology
▪History of cytology:
•Anton van Leeuwenhoek (1632-1723): 1
st
recorded observations of
bacterial cells (termed “animalcules”) from pond water and tooth
scrapings.
Anton van Leeuwenhoek and his hand lens

8. Introduction of cell biology
Anton van Leeuwenhoek and his hand lens
•Microscopic observations by Anton van Leeuwenhoek

9. Introduction of cell biology
▪History of cytology:
•The term cell – Robert Hooke (1635-1703) the mid 17
th
century to
describe the structure of cork.
•Anton van Leeuwenhoek (1632-1723): 1
st
recorded observations of
bacterial cells (termed “animalcules”) from pond water and tooth
scrapings.
•1830s: the importance of cells realized.
•1838: German botanist Matthias Schleiden (1804-1881) observed
that despite differences in tissue structure, all plants tissues were
made of cells.

10. Introduction of cell biology
▪History of cytology:
•The term cell – Robert Hooke (1635-1703) the mid 17
th
century to
describe the structure of cork.
•Anton van Leeuwenhoek (1632-1723): 1
st
recorded observations of
bacterial cells (termed “animalcules”) from pond water and tooth
scrapings.
•1830s: the importance of cells realized.
•1838: German botanist Matthias Schleiden (1804-1881) observed
that despite differences in tissue structure, all plants tissues were
made of cells.

11. Introduction of cell biology
▪History of cytology:
•1838: German botanist Matthias Schleiden (1804-1881) observed
that despite differences in tissue structure, all plants tissues were
made of cells.
Matthias Schleiden German botanist

12. Introduction of cell biology
▪History of cytology:
•1839 – German zoologist Theodor Schwann (1810-1882) realized
animals were also composed of fundamental cellular units or cells.
•Schwann proposed 1
st
2 principles of cell theory:
•All organisms consist of one or more cells.
•The cell is the structure unit of life
Theodor Schwann (1810-1882)

13. Introduction of cell biology
▪History of cytology:
•Schleiden-Schwann realized could arise from non-cellular materials.
•German physician Rudolf Virchow (1821-1902)
demonstrated that living cells (biogenesis), and
not from inanimate matter (abiogenesis).
Rudolf Virchow (1821-1902)

14. Introduction of cell biology
What is the Cell Definition?
▪The cell: is the smallest unit of life.
▪The cell: is the basic structural, functional, and biological unit of all known organisms,
except viruses.

15. Introduction of cell biology
▪What is the Cell?
•The cells from latin cella, or cellula
meaning “Small room”.

16. Introduction of cell biology
▪A.G. Loewry and P. Siekevitz (1963) have defined a cell as “a unit of biological
activity delimited by a semi-permeable membrane and capable of self-
reproduction in a medium free of other living systems”.

17. Introduction of cell biology
1.Highly complex and organized.
2.Possess a genetic program and the means to use it.
▪Properties of a Cell:

18. Introduction of cell biology
3.Capable of producing more of themselves.
4.Capable of self-regulation.
▪Properties of a Cell:

19. Introduction of cell biology
5.Acquire and utilize energy.
6.Carry out a variety of chemical reactions.
▪Properties of a Cell:

20. Introduction of cell biology
7.Engage in mechanical activities.
8.Able to respond to stimuli.
▪Properties of a Cell:

21. Introduction of cell biology
▪The cell is of two types:
1- Eukaryotic which are contain a nucleus.
e.g. Plant & animal.
2- Prokaryotic which do not.
e.g. Bacteria
Cells
Eukaryotic
Plant Animal
Prokaryotic
Bacteria

22. Introduction of cell biology
▪The cell is of two types:

23. Introduction of cell biology
Prokaryotic Eukaryotic
Size Small (1-10µm), unicellular.Large (10-100µm),
multicellular.
Cell membraneSingle membrane and cell wall.Membrane bilayer.
Nucleus No nucleus. Nucleus.
DNA Circular DNA. Linear DNA.
Histone No histones. Histones.
Cell organellesNo cell organelles. Membrane bond
organelles.
Ribosomes Free in cytoplasm. 50S
+30S (70S).
On surface of ER. 60S
+40S (80S).
Cell divisionFission. By Mitosis.
Cytoskeleton Absent, has flagella. Present.
Examples Bacteria. Plants & Animals.

24. Introduction of cell biology

25. Introduction of cell biology
▪The organisms can be classified as a
unicellular (consisting of a single cell
such as bacteria), or multicellular
(including plants and animals)
Amoeba sp

26. Introduction of cell biology

27. Introduction of cell biology

28. Introduction of cell biology
▪The organisms can be classified as a
unicellular (consisting of a single cell
such as bacteria), or multicellular
(including plants and animals)
Human

29. Introduction of cell biology
▪Cell consists mainly of two components (Protoplasm):
1.Centric nucleus.
2.Cytoplasm enclosed within a
cell-membrane.

30. Introduction of cell biology
▪The protoplasm surrounded the nucleus is known as “Cytoplasm”,
While that of the nucleus is known as “Karyoplasm”.

31. Cellular organelles

32. Cell membrane
▪Thinmembranethat surrounds every
livingcell, delimiting the cell from
theenvironmentaround it.
▪Cell membrane (also known as the
plasma membrane).
▪ A phospholipid bilayer with proteins,
Protein = 40% and lipid = 60%.
❖Composition:

33. Cell membrane
1.Separates the interior of the cell from the
outside environment.
2.It also provides a fixed environment inside
the cell, and that membrane has several
different functions.
3.Provides protection for a cell.
4.Also provides some structural support for a
cell.
❖Function:

34. Cell membrane
5.The cell membrane regulates the
transport of materials entering and
exiting the cell.
6.One is to transport nutrients into the
cell and also to transport toxic
substances out of the cell.
❖Function:

35. Cytoplasm
▪Everything in a cell except the nucleus is
cytoplasm.
▪Clear, gelatin-like, watery substance
surrounding the organelles.
•Water = 90%
•Organic and inorganic compounds = 10%
❖Composition:

36. Cytoplasm
1.Maintains the shape and consistency of the cell.
2.Allows for chemical reactions necessary in metabolism.
3.Site for many metabolic pathway.
Ex: glycolysis, protein synthesis, fatty acid synthesis, purine synthesis.
❖Function:

37. Nucleus
▪Nucleus, inbiology, a specialized structure occurring in
mostcells(exceptbacteriaandblue-green algae).
▪It separated from the rest of the cell by a
double layer, thenuclear membrane. This
membrane seems to becontinuouswith
theendoplasmic reticulum(a membranous
network) of the cell and has pores, which are
probably permit the entrance of large
molecules.

38. Nucleus
1.The nucleus controls and regulates the activities
of the cell (e.g., growth andmetabolism).
2.Carries thegenes, structures that contain the
hereditary information.
3.It primarily serves as the information center of
the cell.
❖Function:

39. Centrioles
▪“Centriole is an organelle, cylindrical in shape,
that is composed of a protein called tubulin.”
▪They are usually present near the nucleus but
are not visible when the cell is not dividing.
❖Centriole Definition

40. Centrioles
1.In spite of being devoid of DNA, the centrioles are
capable of forming new centrioles.
2.They can be transformed into basal bodies, and the
basal bodies give rise to flagella and cilia.
3.They help in cell division by forming microtubule
organizing centers.
4.Out of the two centrioles, the distal centriole forms
the tail or axial filament.
❖Function:

41. Mitochondria
▪Mitochondrion, membrane-boundorganellefound
in thecytoplasmof almost alleukaryoticcells(cells
with clearly defined nuclei).
▪Mitochondria are typically round to oval in shape and
range in size from 0.5 to 10μm.
▪Mitochondria are unlike other cellular organelles in
that they have two distinctmembranesand
auniquegenome.
▪It reproduce bybinary fission; these features indicate
that mitochondria share an evolutionary past
withprokaryotes(single-celled organisms).

42. Centrioles
1.The primary function of which is to generate large quantities
of energy in the form ofadenosine triphosphate(ATP).
2.In addition to producing energy, mitochondria
storecalciumforcellsignaling activities, generate heat, and
mediate cell growth and death.
❖Function:

43. Golgi apparatus
▪Golgi apparatus, membrane-boundorganelleofeukaryoticcells
(cells with clearly defined nuclei) that is made up of a series of
flattened, stacked pouches calledcisternae.
▪It is located in thecytoplasmnext to theendoplasmic
reticulumand near thecell nucleus.

44. Golgi apparatus
▪In general, the Golgi apparatus is made up of approximately four
to eight cisternae, although in some single-celled organisms it
may consist of as many as 60 cisternae.
▪The cisternae are held together bymatrixproteins, and the whole
of the Golgi apparatus is supported by cytoplasmicmicrotubules.

45. Golgi apparatus
▪The three primary compartments of the apparatus are
known generally as “cis” (cisternae nearest the
endoplasmic reticulum), “medial” (central layers of
cisternae), and “trans” (cisternae farthest from the
endoplasmic reticulum).
▪Two networks, the cis Golgi network and the trans
Golgi network, which are made up of the outermost
cisternae at the cis and trans faces, are responsible for
the essential task of sorting proteins and lipids that
are received (at the cis face) or released (at the trans
face) by the organelle.

46. Golgi apparatus
1.Packaging and secretion of proteins.
2.It receives proteins from Endoplasmic Reticulum. It packages it into
membrane-bound vesicles, which are then transported to various destinations,
such as lysosomes, plasma membrane or secretion.
3.They also take part in the transport of lipids and the formation of lysosomes.
4.Post-translational modification and enzymatic processing occur near the
membrane surface in Golgi bodies, e.g. phosphorylation, glycosylation, etc.
5.Golgi apparatus is the site for the synthesis of various glycolipids,
sphingomyelin, etc.
❖Function:

47. Endoplasmic Reticulum (ER)
▪Endoplasmic reticulum (ER), inbiology, a continuousmembranesystem that forms a
series of flattened sacs within thecytoplasmofeukaryotic cells.
▪It serves particularly in the synthesis, folding, modification, and transport ofproteins.
▪Differences in certain physical and functional characteristics distinguish the two types of ER,
known as rough ER and smooth ER.

48. Endoplasmic Reticulum (ER)
Rough Endoplasmic Reticulum (RER)Smooth Endoplasmic Reticulum (SER)

49. Endoplasmic Reticulum (ER)
Rough Endoplasmic Reticulum (RER) Smooth Endoplasmic Reticulum (SER)

50. Endoplasmic Reticulum (ER)
Rough Endoplasmic Reticulum (RER)
▪Rough ERis named for its rough appearance,
which is due to theribosomesattached to its
outer (cytoplasmic) surface.
▪Rough ER lies immediatelyadjacentto the
cellnucleus, and its membrane is continuous
with the outer membrane of the nuclear
envelope.
▪The ribosomes on rough ER specialize in the
synthesis of proteins that possess a signal
sequence that directs them specifically to the
ER for processing.

51. Endoplasmic Reticulum (ER)
Smooth Endoplasmic Reticulum (SER)
▪The smooth ER is involved in the synthesis oflipids,
includingcholesterolandphospholipids, which are used in
the production of new cellular membrane.
▪In certain cell types, smooth ER plays an important role in
the synthesis ofsteroid hormonesfrom cholesterol.
▪In cells of theliver, it contributes to the detoxification
ofdrugsand harmful chemicals.
▪Thesarcoplasmic reticulumis a specialized type of smooth
ER that regulates the calciumionconcentration in the
cytoplasm ofstriated musclecells.

52. THANK YOU