3. Discovery of Cells
Robert Hooke (1665)
🞑 Observed sliver of cork
🞑 Saw “row of empty boxes”
🞑 Coined the term cell
4. Cell theory
(1839)Theodor Schwann & Matthias Schleiden
“ all living things are made of cells”
(1855) Rudolf Virchow
“Omnis cellula e cellula ” all cells arise from pre-
existing cells
5. Principles of Cell Theory
All living things are made of cells
Smallest living unit of structure and
function of all organisms is the cell
All cells arise from preexisting cells
(this principle discarded the idea of
spontaneous generation)
8. Characteristics of All Cells
A surrounding membrane
Protoplasm – cell contents in thick fluid
Organelles – structures for cell function
Control center with DNA
11. Prokaryotic Cells
No membrane bound nucleus
Nucleoid = region of DNA concentration
Organelles not bound by membranes
12. Eukaryotic Cells
Nucleus bound by membrane
Include fungi, protists, plant, and
animal cells
Possess many organelles
Protozoan
13.
14. THE UNIVERSE INSIDE OUR
CELLS
Zoom into your own body to see the
different cells that make up your
heart, brain and bones.
These trillions building block of cells
are communicating with each other
every moment of our lives.
As the house is made by BRICKS.
19. CELL ORGANELLES
The cellular components are called the Cell
Organelles.
These cell organelles are membrane-bound,
present within the cells and are distinct in their
structures and functions.
They coordinate with their functions efficiently
for the normal functioning of the cell.
There are various organelles present within
the cell and are classified into three categories
based on the presence or absence of
membrane.
20. TYPES OF CELL
ORGANELLES
Organelles without membrane: The Cell wall,
Ribosomes, Centrosome and Cytoskeleton are
without membrane-bound cell organelles.
Single membrane-bound organelles: Vacuole,
Lysosome, Golgi Apparatus, Endoplasmic
Reticulum are single membrane-bound organelles
present only in a eukaryotic cell.
Double membrane-bound
organelles: Mitochondria and chloroplast are
double membrane-bound organelles present only
in a eukaryotic cell.
22. Movement Across the Plasma Membrane
A few molecules move freely
🞑 Water, Carbon dioxide, Ammonia, Oxygen
Carrier proteins transport some molecules
🞑 Proteins embedded in lipid bilayer
🞑 Fluid mosaic model – describes fluid nature of a
lipid bilayer with proteins
23.
24. Membrane Proteins
1. Channels or transporters
🞑 Move molecules in one direction
2. Receptors
🞑 Recognize certain chemicals
26. CELL MEMBRANE FUNCTION
Passive Transport
Active Transport
Endocytosis
(phagocytosis & pinocytosis)
Exocytosis
27. Passive Transport
No energy required
Move due to gradient
🞑 differences in concentration, pressure, charge
Move to equalize gradient
🞑 High moves toward low
28. Types of Passive Transport
1. Diffusion
2. Osmosis
3. Facilitated diffusion
30. Osmosis
Special form of diffusion
Fluid flows from lower solute concentration
Often involves movement of water
🞑 Into cell
🞑 Out of cell
31. Solution Differences & Cells
solvent + solute = solution
Hypotonic
🞑 Solutes in cell more than outside
🞑 Outside solvent will flow into cell And
cell will swell
Isotonic
🞑 Solutes equal inside & out of cell no
transport
Hypertonic
🞑 Solutes greater outside cell
🞑 Fluid will flow out and shrink
32.
33. Facilitated Diffusion
Differentially permeable membrane
Channels (are specific) help molecule or
ions enter or leave the cell
Channels usually are transport proteins
(aquaporins facilitate the movement of
water)
No energy is used
34. Process of Facilitated Transport
Protein binds with molecule
Shape of protein changes
Molecule moves across membrane
36. Endocytosis
Movement of large material
🞑 Particles
🞑 Organisms
🞑 Large molecules
Movement is into cells
Types of endocytosis
🞑 bulk-phase (nonspecific)
🞑 receptor-mediated (specific)
37. Process of Endocytosis
Plasma membrane surrounds material
Edges of membrane meet
Membranes fuse to form vesicle
47. Endoplasmic Reticulum
Helps move substances within cells
Network of interconnected membranes
Two types
🞑 Rough endoplasmic reticulum
🞑 Smooth endoplasmic reticulum
48. Rough Endoplasmic Reticulum
Ribosomes attached to surface
🞑 Manufacture protiens
🞑 Not all ribosomes attached to rough ER
May modify proteins from ribosomes
51. Golgi Apparatus Function
1. Molecules come in vesicles
2. Vesicles fuse with Golgi membrane
3. Molecules may be modified by Golgi
52. Golgi Apparatus Function
(Continued)
4. Molecules pinched-off in separate vesicle
5. Vesicle leaves Golgi apparatus
6.Vesicles may combine with plasma membrane
to secrete contents
53.
54. Lysosomes
Contain digestive enzymes
Functions
🞑 Aid in cell renewal
🞑 Break down old cell parts
🞑 Digests invaders
55. CELL ORGANELLES DISCOVERY
1 NUCLEUS 1 ROBERT BROWN(1831)
2 GOLGI BODY 2 CAMEILLIO GOLGI
3 PLASMA MEMBRANE 3 SCHWANN(1838)
4 CYTOPLASM 4 STRASBURGER(1882)
5 ENDOPLASMIC RETICULUM 5 PORTER(1943)AND NAMED
IN(1953)
6 MITOCHONDRIA 6 ALTAMAN(1894)AND
NAMED BY BENDA(1897)
7 LYSOSOME 7 de DUVE(1955)
8 VACUOLES 8 SPALLANZONI
9 RIBOSOMES 9 ROBINSON AND BROWN
(1953) IN PLANT CELL AND
PALADE(1955) IN ANIMAL
CELL
10 MICROBODIES 10 RHODIN(1954)
(a)PEROXIXOMES (a)de DUVE(1965)
(b)GLYOXYSOME (b)BRIEDENBACH(1967)