A Brief History of the Cell and it's Anatomy

Contains a brief overview of the history of the cell and its parts

1. The CELL
http://papercastlepress.com/blog/wp-content/uploads/2008/11/cells.jpg

3. Anton Van Leeuwenhoek
•Made the first
compound microscope
Robert Hooke
- Coined the word “cell” from
his observation of mass of
tiny cavities from thin slices
of cork

5. Robert Brown
- Discovered cell nucleus
and cytoplasmic streaming
Johannes Purkinje
- Introduced the scientific
term plasma and protoplasm

6. Matthias Schleiden
– concluded all plants are
made of cells
Theodore Schwann
- concluded all living things
are made up of cells

7. Rudolf Virchow
- Concluded that all cells arise
from pre-existing cells
Louis Pasteur
-Proved that cell arise
from preexisting cells
-Proposed the Theory of
Biogenesis

8. Cell Theory
•Formulated by Schwann, Schleiden, & Virchow
•Principles:
1.Every living organism is made up of one or
more cells.
2.The smallest living organisms are single cells,
and cells are the functional units of
multicellular organisms.
3.All cells arise from preexisting cells.
•Theory:
–All living things are made up of cells, and
these cells arise from pre-existing cells.

9. Major Types of Cells
1.Prokaryotic cells
•Small, single-celled organisms that lack a nuclear
envelope, histones, and membranous organelles.
•Domains Bacteria and archaea
2.Eukaryotic cells
•Components of multicellular organisms, cells
which have the structures that are absent in
prokaryotic cells.
•Protists, plants, fungi, and animals

10. Types of Cells

11. •Protoplasm
•Substance that exhibits the properties and activities
of life
•The living material of the cell
•The region which contains the nucleus, cytoplasm,
and cytoplasmic organelles
•Cytoplasm
•The cell content between the nucleus and the cell
membrane
•The most active region of the cell due to numerous
biochemical reactions of the organelles, and the
inclusions.
•Organelle
•Subcellular structure

12. Parts of a Cell
A.Cell Surface
1.Cell wall
2.Cell membrane
3.Cell coat / glycocalyx
Function: isolation and communication
B.Cytoskeleton
1.Microtubules
2.Microfilaments
3.Intermediate filaments
Function: shape, support, movement
C.Cytoplasm – ground substance of the cell

13. D.Cellular Organelles – structures found in the cytoplasm
1.Mitochondria Energy suppliers
2.Chloroplast
3.Ribosome
4.Endoplasmic reticulum Manufactures
5.Golgi complex or apparatus
6.Lysosome - digestion
7.Plastids Storage and elimination
8.Vacuoles

14. E.Nucleus
1.Nuclear envelope
2.Nuclear sap
3.Nucleolus
4.Chromatin (chromosomes)
Function: control or regulation of activity
of the cell

15. Plant Cell Animal Cell
http://millville.sps.edu/allaccess/divisions/science/jdonnelly/Cell%20Page_files/04-05A-AnimalCell-L.jpg

16. I.CELL SURFACE
A. CELL WALL
•Outermost part in
cells of plant, fungi,
and most bacteria
•Located outside the
cell membrane
•Entirely separate from
the cell membrane
•Protection, maintains
shape, and prevents
excessive uptake of
water
Plant Cell
http://millville.sps.edu/allaccess/divisions/science/jdonnelly/Cell%20Page_files/04-05B-PlantCell-L.jpg

17. Main structural components of Cell Wall:
•Cellulose – plants
•Chitin – fungi
•Murein – bacteria; a polysaccharide chain
covalently crosslinked by amino acids

18. •Cell wall layers:
1.Primary wall
─thin & flexible wall first secreted at young age of plant.
─Outermost layer made of:
- cellulose, hemicellulose, and glycoproteins
http://www.bio.miami.edu/~cmallery/150/cells/plasmodesmata.jpg

19. 2.Middle lamella
− a thin layer rich in sticky polysaccharides called
pectin
−It glues adjacent cells together

20. 3.Secondary wall
•Contains lignin which adds rigidity to the cell wall or
make it stiffer (less flexible and almost inelastic)
•strong and durable matrix that protects and support
the cell.

21. Commercial Importance:
•Cellulose – main component of paper, wood,
cotton, rayon, flax, celluloid
•Lignin – extracts from wood, used in manufacture
of synthetic rubber, adhesive, pigments, vanillin

22. B. CELL (plasma) MEMBRANE
•A semi-permeable membrane enclosing the cell
•It governs the interactions between a cell and its external
environment.
•Functions:
1.Isolates the contents of the cell from its external
environment
2.Controls the entrance and exit of substances into and
out of the cell
3.Communicates with other cell
•Composition:
–Contains proteins, lipids and carbohydrates
–A lipid bilayer with proteins intercalated in or
adherent to both surfaces.

23. Plasma
Membrane

24. C. Cell Coat
•Found in animals and bacteria
•Also called the glycocalyx
•Composition:
•Oligosaccharides covalently bonded to either protein
(glycoprotein) or lipid (glycolipid) molecules in the
cell membrane
•Contains enzyme and antigen
•Function:
•Provides recognition sites on the cell surface enabling
it to interact with other cells.
•Ex. Glycoproteins in RBC determines blood type and
serve as identification molecules

25. Cell Coat
http://www.proprofs.com/flashcards/story.php?title=mcb-block-3-organelles-cell-membrane

26. II.CYTOSKELETON
•A network of protein fibers to which most of
cell organelles are attached
•“skeleton” of the cell
•Functions:
•maintains cell shape and provides support
•anchors organelles & enzymes to specific regions of
the cell
•contractility and movement (amoeboid movement)
•intracellular transport - tracks for vesicle and
organelle movement by motor proteins

27. Components of Cytoskeleton:
1.Microtubule
•hollow tubes of tubulin (a
globular protein)
•Functions:
•maintains cell shape
•anchor organelles
•movement of organelles
•track for motor proteins
http://www.uic.edu/classes/bios/bios100/lecturesf04am/cytoskeleton02.jpg

28. http://classes.midlandstech.edu/carterp/Courses/bio210/chap03/lecture1.htm

29. Microtubular Organelles
1.Cilia and Flagella
•Whip-like extensions of the cell membrane for
cellular movement
•Cilia occur in protozoans like Paramecium and in
flame cells of flatworms, and in in epithelial cells
lining moist regions of the body.
•Flagella occur in protozoans like Euglena
•both arranged in a9+2pattern with dynein arms
projecting outward

30. Structure of Cilia and Flagellum
•surrounded by a
membrane
•It encloses a matrix
containing a supporting
shaft or axoneme
•movement of cilia and
flagella is brought about
by sliding of the nine
double microtubules
past each other, using
energy from ATP
http://www.tutorvista.com/content/biology/biology-iii/cell-organization/nonmembranous-cell-organelles.php#cilia-and-flagella

31. Cilia Flagella
Number Numerous Few: 1 pair or less
Length Short (10-25 µm) Long (50 – 75 µm)
Direction of
movement
Parallel to cell
membrane
Perpendicular to cell
membrane

32. Ciliary and Flagellar Movements
•metachronous
beat, cilia of a row
beat one after the
other
•isochronous
rhythm all the cilia
of a row beat
simultaneously

33. 2. Centrioles
•two short, hollow,
cylinders usually lying at
right angles to each
other
•made up of nine
microtubule triplets,
which lie evenly spaced
in a ring
•no microtubules in the
center (9+0
arrangement)
•Found in protists, fungi
and lower plants but
lacking in higher plants.

34. 3. Basal Bodies
•basal granules or kinetosomes
•structures, which bear cilia and flagella
•exhibit a structure, which is exactly similar to
a centriole
•a centriole can become a basal body and a
basal body can become a centriole by losing
the cilium or flagellum

35. Components of Cytoskeleton:
2.Microfilaments
•solid protein (actin)
which is assembled at
one end and
disassembled at the
other end
•maintain cell shape by
resisting tension (pull)
•used in cell division
•muscle contraction
http://www.uic.edu/classes/bios/bios100/lecturesf04am/cytoskeleton02.jpg

36. Components of Cytoskeleton:
3.Intermediate
filaments
•rope-like fibrous proteins
•Protein sub-units: keratin,
vimentin, lamin
•provide structural reinforcement
by resisting tension (pull)
•anchor organelles
•keep nucleus in place
http://www.uic.edu/classes/bios/bios100/lecturesf04am/cytoskeleton02.jpg

37. Types of intermediate filaments:
1.Keratin filaments or tonofilaments
–Present in epithelial cells and contain keratins
2.Neurofilaments
–Present in axons, dendrites and perikaryon of neurons
3.Glial filaments
–Present in astrocyte (star-shapedglialcellsin
thebrainand spinal cord); contains a very acidic
protein
4.Heterogenous filaments
–Same morphology and location as glial filaments but
with different proteins

39. III.CYTOPLASM
•The material contained within the plasma membrane of a
cell, exclusive of the nucleus.
•The most active region of the cell due to numerous
biochemical reactions of the organelles, and the inclusions.
•Cytosol – the fluid part of the cytoplasm

40. Cytoplasmic structures:
1.Organelles
–Membrane-bound, Physiologically active,
permanent sub-cellular structures performing
metabolic functions.
2.Cytoplasmic inclusions
–Structures that are generally transient than
organelles and less actively involves in cell
metabolism
3.Cytoskeleton
–Supporting network of the cell

41. IV. CELLULAR
ORGANELLES
Structures found in the
cytoplasm including the
nucleus

42. A. MITOCHONDRIA
•“powerhouse” of the cell
•Structure:
•Size: 2-6 µm in length and 0.2 µm
in diameter
•Shapes: spherical, ovoid,
filamentous
•Bounded by two unit membranes:
1.Outer mitochondrial membrane
•Smooth contour and forms
a continuous porous
covering
2.Inner mitochondrial membrane
•Semipermeable with
infoldings, “cristae”
•2 membrane limited space:
•Intermembrane space
•Intracristal space
http://academic.brooklyn.cuny.edu/biology/bio4fv/page/mito.gif

43. •Mitochondrial matrix
•Contains water, solutes, and large matrix granules
•Has circular DNA and mitochondrial ribosomes
•Soluble enzymes involved in citric acid cycle, lipid
oxidation, mitochondrial protein and DNA synthesis
•Self replicating
•Function:
•Provides energy in a form of ATP
•Synthesize their own DNA and some proteins
•Location:
•Occur in all eukaryotic cells
•Dipersed throughout the cytoplasm

44. B. CHLOROPLAST
•A specialized member of a
family of closely related
plant organelles called
plastids.
•Contain the green pigment,
chlorophyll, which captures
the energy of sunlight to
drive the synthesis of sugar
from CO2 and H2O
(photosynthesis)
•‘food factory” of the cell
•Contain DNA and ribosomes
•self replicating
http://micro.magnet.fsu.edu/cells/chloroplasts/images/chloroplastsfigure1.jpg

45. Chloroplast Structure
•Double-membrane organelle
•Oblong, ellipsoidal shape
•Composed of:
a.Outer membrane
b.Inner membrane
c.Stroma – semifluid material
enclosed by the inner
membrane
d.Thylakoids – interconnected,
hollow, disk-shaped
flattened sacs embedded
within the stroma
•Contain the chlorophyll
e.Granum – stack of thylakoids
http://micro.magnet.fsu.edu/cells/chloroplasts/images/chloroplastsfigure1.jpg

46. http://www.biology.iupui.edu/biocourses/N100/images/ch9chloroplast.jpg

47. B. RIBOSOMES
•Dark granules that carry out protein synthesis in cells
•Synthesized in the nucleus
•Structure:
–Have 2 unequal ribosomal subunits:
•small subunit - recognizes and binds mRNA
•Large subunit - catalyzes the addition of amino
acids to the growing protein chain and binds
molecules of tRNA
–They join together to form the polyribosome
•Distribution:
a.Cytoplasm
b.Attached to the endoplasmic reticulum
c.Attached to the nuclear envelope

48. •Types of Ribosomes:
1.Free ribosomes
–Dispersed in the cytoplasm
–Cells with mostly free ribosomes retain most
of the proteins they manufacture
2.Attached ribosomes
– cells with many ribosomes lining an
enormous endoplasmic reticulum – secrete
proteins, e.g. cells of the pancreas that
produce digestive enzymes
•Composition:
–RNA and protein

49. C.ENDOPLASMIC RETICULUM (ER)
-made of membranous tubules and sac called cisternae
- discovered and named by Keith Porter in 1945
http://micro.magnet.fsu.edu/cells/endoplasmicreticulum/images/endoplasmicreticulumfigure1.jpg

50. - Involved in the synthesizing,
packaging, and processing of various
cell substances
•2 forms:
1.Rough ER (RER)
➢ Structure:
–Granular ER, studded with ribosomes in
polysomal clusters
–Its cisternae are typically parallel, flattened, and
elongated, especially in cells specialized for
protein secretion (eg, pancreatic acinar cells,
plasma cells)

51. Functions of RER:
•Synthesize:
•Proteins for sequestration from the
cytoplasm
•Secretory proteins (collagen)
•Proteins for insertion into cell
membranes (integral proteins)
•Lysosomal enzymes
•Location of RER:
•Suspended in the cytoplasm and shows
continuity with the nuclear envelope’s
outer membrane
•In protein-secreting epithelial cells it lies in
the basal cytoplasm, between the plasma
membrane the nucleus.

52. 2.Smooth ER (SER)
•Structure of SER:
–Lacks ribosomes
–Cisternae are more tubular or vesicular than the RER
–Stains poorly and indistinguishable from the rest of the cytoplasm
(light microscope)
•Cannot synthesize proteins
•Function of SER:
–Major site of lipid synthesis including the phospholipids of the ER
and other membranes
–Site of synthesis and metabolism of phospholipids and fatty acids
–It has many enzymes that are important in lipid metabolism,
steroid hormone synthesis, glycogen breakdown, and
detoxification
•Detoxify chemicals such as pesticides and carcinogens by
converting them into water-soluble forms that can be
excreted out of the body.

53. •Location of SER:
•Suspended in the cytoplasm and abundant in cells
synthesizing hormones (adrenal cortex, gonads), in liver
cells
•Sarcoplasmic reticulum
•a specialized SER found in striated muscle cells, where it
regulates muscle contraction by sequestering and
releasing calcium ions.

54. D. GOLGI APPARATUS
•Center for manufacturing, warehousing,
sorting, and shipping cell products.
http://inferno.slug.org/~emily/Golgi_Aparatus.jpg

55. •Functions:
•Polysaccharide synthesis
•Sorting of secretory products
•Packaging of secretory products
•Concentration and storage of
secretory products
•Location:
•Near the nucleus (juxtanuclear)
and centrioles

57. E. LYSOSOME
•A membrane-
bounded sac of
hydrolytic
enzymes use to
digest
macromolecules.
•Contains more
than 50 enzymes
Formation & Function of Lysosome
http://bioserv.fiu.edu/~walterm/FallSpring/cell_components/4.11B%20Lysosome%20formation%20and.JPG

58. •Enzymes in lysosome:
•Acid phosphatase - phospholipases
•Ribonuclease - proteases
•Deoxyribonuclease - glucosidase
•Cathepsins - lipases
•Sulfatases
•Beta-glucuronidase
•A lack in particular enzyme can result is life-
threatening accumulation of its substrate in the
cytoplasm
•Lysosomal enzymes occur as glycoproteins and are
most active at acidic pH.

59. Kinds:
•Primary Lysosomes
•Small (5-8 nm in diameter), electron-dense contents
•Appear as solid black circles in EMs.
•Lysosomes which stores enzymes that are directly
released from the Golgi complex, however, are mostly
inactive
•Abundant in phagocytic cells (macrophages, neutrophils)
•Secondary lysosomes
•Larger, less electron-dense
•Mottled appearance in Ems
•Digestion produces metabolites for cell maintenance
and growth and aids in organelle turnover.
•Occurs throughout the cytoplasm

60. Types of Secondary lysosomes:
1.Digestive vacuoles
•Result from the association of primary lysosomes
with vacuoles containing phagocytized materials
2.Residual bodies
•Contain undigested material and are eliminated
but some remain in the cell as pigment inclusions
and may be related to the aging process.
3.Phagosomes

61. Phagosomes •Membrane-limited
vesicles of various sizes
containing material
destined for lysosomal
digestion.
•Kinds:
1.Heterophagosomes
•Contain products of
heterophagy, ie,
extracellular material
ingested by phagocytosis
2.Autophagosomes
•Contain products of
autophagy, ie, intracellular
material like worn or
damaged organelles)

62. G. PLASTIDS
•amyloplasts –colorless plastids that stores amylose
• Chromoplasts – have pigments that give fruits and
flowers their orange and yellow color

63. H. VACUOLE
•Sinlge-membraned sac
enclosed by a membrane
called tonoplast.
•Functions:
1.Storage of materials
2.Dumpsite for hazardous
wastes
3.Support & maintainance of
turgor pressure

64. 2.Central vacoule
•Contains water , dissolved
salts, cell products or
metabolic intermediates,
waste products and
pigments
• Types:
1. Contractile vacuoles
–Found in freshwater protozoans
–Contract to expel excess water from the cell

65. I. MICROBODIES
•Small vesicles containing powerful oxidative
enzymes for interconverting organic molecules.
•Types:
1.Glyoxysomes – primarily found in tissues of oil-
bearing seeds where fat is converted to CHO through
the glyoxylate cycle
2.Peroxisomes – function in the metabolism of
glycolate produced by chloroplasts during
photosynthesis
3.Spherosomes – store and transport lipids

66. Peroxisomes
•Membrane-limited, enzyme-containing vesicles slightly
larger than primary lysosomes.
• functions for hydrogen peroxide metabolism
•Contain urate oxidase, hydroxyacid oxidase, and D-amino
acid oxidase, which produce hydrogen peroxide capable of
killing bacteria
•Contain catalase, which oxidizes various substrates and uses
the hydrogen removed in the process to convert toxic
hydrogen peroxide to water
•Participate in gluconeogenesis by assisting in fatty acid
oxidation
•Dispersed in the cytoplasm or in association with SER

67. V. NUCLEUS

68. NUCLEUS
•“governor of the cell”
•It controls and regulates
the function of other
organelles.
•Components:
1.Nuclear Envelope – a membrane that enclosed the nucleus
–Regulates the passage of ions and macromolecules
between the nucleus and the cytoplasm
–Helps to control the information to and from the
nucleus
2.Nucleoplasm – (karyolymph), the colloidal solution
enclosed by the nuclear membrane

69. 3.Chromatin – contains the
linear arrangement of the
basic unit of heredity
called genes.
4.Nucleolus – site of
ribosome synthesis

70. EXTRACELLULAR MATRIX (ECM)
•For support,
adhesion, movement
and regulation of cell
•Glycoproteins
•Main component
of the ECM
secreted by the
cells
•types:
•Proteoglycan
•Collagen fiber
•Fibronectin
http://www.bio.miami.edu/~cmallery/150/memb/fig7x29.jpg

71. •Proteoglycans
•The collagen are
inserted
•Collagen
•The most
abundant in the
ECM
•It forms strong
fibers outside the
cells
•Fibronectin
― Attaches the ECM to the plasma membrane of the cell.
Integrin– receptor protein built in the plasma membrane that interconnect
the ECM and the cytoskeleton

72. INTERCELLULAR JUNCTIONS
–Help integrate cells into higher levels of
structure and function
PLASMODESMATA
•An open channel in the cell wall of
plants through which strands of cytosol
connect from adjacent cells.
•It unifies most of the plant into one
living continuum.

73. http://www.uic.edu/classes/bios/bios100/f06pm/plasmodesmata.jpg

74. Cellular junctions in animals:
A.TIGHT JUNCTIONS
•Prevents the leakage of material between cells.
•Fuses membranes of adjacent cells
•Forms belt around cell
B.DESMOSOMES
•It anchors the cell into strong sheets that is
strengthened by intermediate filament.
C.GAP JUNCTIONS
•Provides channel between adjacent cells just large
enough for passage of small ions and molecules.

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Sept. 21, 2020
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