III Pharm.D -Pharmacology II - The Dynamic Cell - III Pharm.D - The Dynamic Cell - Cellular classification, subcellular organelles ppt. As per PCI syllabus

1. “THE DYNAMIC CELL”
Cellular classification &
Subcellular organelles
By: Dr.S.Kameshwaran

2. CELLULAR CLASSIFICATION
 Two main classes of cells - so far!
 Prokaryotic cells - All Bacteria & Archaea - no
nucleus
 Eukaryotic cells - Plants, animals, fungi, and
protists - all have a nucleus
 Prokaryotes also lack organelles or cytoskeleton
 They function very much the same.

3. Prokaryotes vs. Eukaryotes
PROPERTY
Nucleus
Cell Diameter
Cytoskeleton
Organelles
DNA content (bp)
Chromosomes
Procaryotes
Absent
1 um
Absent
Absent
1x10E6 to 5x10E6
Single circular DNA
molecule
Eucaryotes
 Present
 10 - 100 um
 Present
 Present
 1.5x10E7 to 5x10E9
 Multiple linear DNA
molecules

4. The cell
Latin cella - "small room"
Cell is the basic structural, functional, and
biological unit of all known living organisms.
Cells are the smallest unit of life that can
replicate independently, and are often called the
"building blocks of life".
The study of cells is called cell biology.
humans contain about 100 trillion cells,
cells are visible only under the microscope
SIZE ~ 10–100 micrometres
discovered by Robert Hooke in 1665

5. THE SUB CELLULAR ORGANELLES:
 Plasma membranes
 Cytoplasm
 Mitochondria
 Smooth Endoplasmic Reticulum
 Rough Endoplasmic Reticulum
 Golgi Complex
 Ribosomes
 Nucleus
 Central Vacuole
 The Cytoskeleton
 Lysosome

7. CELL MEMBRANE:
Also known as plasma membrane/plasmalemma
The cell membrane is the outer coating of the cell
Consist of two layers of phospholipids with proteins
and Carbohydrates embedded in them
- Phospholipid bilayer
Phospholipids are lipid molecules with a charged
phosphate group at one end
Phosphate groups - hydrophilic in nature
Lipid molecules - hydrophobic in nature
Phospholipid molecules have Head & tail portions
Phosphate – head portion
Lipid – tail portion
Tail portions joins one another – creating a lipid
bilayer

9.  Cell membrane having the proteins in its
structure
 They provide the channels in the membrane
- helps in the passage of electrolytes and
non lipid soluble substances
Functions of proteins:
 Act as receptors
 Some are enzymes
 Channels filled with water – allows very
small amount of water soluble substances
across cell membrane
 CH attached to the proteins – immunity

11. Functions:
 Protection of the cell
 Provide specific shape to the cell
 Separate from surrounding
 permeability

12. ORGANELLE:
 Cell contains plasma membrane enclosing a
number of organelles suspended in watery
fluid called cytosol or cytoplasm
 An organelle is a membrane-bound
structure that carries out specific activities
for the cell.

15. CYTOPLASM:
Cytoplasm is the fluid that fills a cell. Scientists
used to call the fluid protoplasm.
The cytoplasm comprises
cytosol (the gel-like substance enclosed within
the cell membrane) – and the organelles.
The organelles are flatting in it
The cytoplasm is about 80% water and usually
colorless.
The cytoplasm has many different molecules
dissolved in solution, fatty acids, sugars, amino
acids & Waste products

16. MITOCHONDRIA:
Power house of the cell
sausage shaped structure
Size: 0.5µm -1µm in diameter up to 7µm in length
converting oxygen and nutrients into
 adenosine triphosphate (ATP)
This process is called aerobic respiration
GLUCOSE O2 ATP
ATP is the chemical energy "currency" of the cell
Their presence depends on the nature of cell and energy need.
Greater number of mitochondria present in liver & muscles

18.  A mitochondria contains outer and inner membranes.
 These are made of phospholipid double layers and
proteins.
there are five distinct compartments within the
mitochondrion. They are:
1.the outer mitochondrial membrane,
2.the intermembrane space (the space between the outer
and inner membranes),
3.the inner mitochondrial membrane,
4.the cristae (space formed by infoldings of the inner
membrane), and
5.the matrix (space within the inner membrane).

19. Function:
Performs aerobic respiration to create energy
for the functioning of the cell
Regulation of cellular anabolism and
catabolism
Synthesis of steroid

20. RIBOSOMES:
It is a tiny granules composed of RNA and protein
They synthesis proteins from amino acids using
RNA template
They make proteins for the use with in cell
Also found on the outer surface of the nuclear
envelope and rough endoplasmic reticulum
They manufacture the proteins and export from the
cell
Ribosomes consist of two major components: the
small ribosomal subunit, which reads the RNA, and
the large subunit, which joins amino acids to form
protein.
Eukaryotes have 80S ribosomes, each consisting of
a small (40S) and large (60S) subunit

23. ENDOPLASMIC RETICULUM
 A network of interconnecting folded membranes
extends from nuclear envelope in the cytoplasm
 2 types:
– Rough ER
• Contains Ribosomes – gives rough nature
– Smooth ER
• Lack in Ribosome
• Extends from Rough ER

25. Functions:
Smooth ER:
Synthesizes lipids
Synthesis of steroidal hormones Eg: Progesterone, Estrogen,
Testosterone
Detoxification of some drugs
Rough ER:
It is studded with ribosome
Involves in protein synthesis – collected in to RER
Exchanges materials with in the cytosol

26. GOLGI APPARATUS
 It is a folded compressed membranous sacs- -
cisternae and vesicles.
 involved in secretion and intracellular transport.
 It works in combination with ER.
 Has incoming and outgoing vesicles.
 Proteins move from ER to the golgi apparatus
where they packed in to membrane bound vesicles
 Then the vesicles are stored
 When needed move to the plasma membrane and
fuse with it
 The contents are expelled from cell - exocytosis

28. Nucleus
The nucleus serves as the cell’s control center,
6μm dia
 Occupies about 10% of total cell volume
 Contains
 Nuclear Envelope
 Nuclear Pore
 Nucleoplasm
sending directions to the cell to grow, mature, divide, or
die.
It also houses DNA (deoxyribonucleic acid), the cell’s
hereditary material.
The nucleus is surrounded by a membrane called the
nuclear envelope, which protects the DNA and
separates the nucleus from the rest of the cell

30. Nuclear envelope
 Inner & outer membrane, arranged parallelly, separated by
10 to 50 nm thick
 Barrier to prevent macromolecules from diffusing freely
Nuclear pores,
 provide aqueous channels through the envelope,
 composed of multiple proteins, referred to as nucleoporins.
 100 nm dia. in size. Mammalian cell will have about 3000 to
4000 pores
Nucleoplasm → similar to cytoplasm
 It is a complex crystallo colloidal system
 Consist of different molecules and enzymatic proteins
 Histones/Protamine's coupled with nucleic acid to form
nucleoproteins

31. CHROMATIN
Chromatin materials saturated with DNA
It is the combination of DNA and proteins (histones)
By the process of coiling and super coiling forms chromosomes.
 Typical human cell → 46 chromosomes
 Chromosomes: DNA bound proteins – carry genetic information's

32. Lysosomes
 Greek word: Lysis – separate, soma – body
 Vary in size 0.1 1.2 micrometer
 Generally known as suicide bag because of its role in
autolysis
 Engulfed virus or bacteria, damaged organelles & food
materials present with in the cell are digested by
liposomes

33. The Cytoskeleton
 Protein filament extends throughout cytosol
 Provides the structural framework
 Three filamentous proteins contributes are
 Microfilaments (actin)
 Intermediate filaments
 Microtubules

34. Vacuoles
 Enclosed compartments which are filled with water
containing inorganic and organic molecules
 No basic shape or size;
 structure varies according to the needs of the cell
 Isolating materials (harmful or a threat to the cell)
 Transports waste products out.
 Maintaining internal hydrostatic pressure
 Maintaining an acidic internal pH

35. THANK U