Dr. Dhiraj J. Trivedi SDM College Of medical Sciences and Hospital Dharwad, Karnataka, India

2. CELL STRUCTURE

4. NUCLEUS Information processing and
administrative center of the cell
Most prominent organelle present
in the cell
Occupies 10% of total cell volume
Size varies with the cell type
Every cell of human body contain
nucleus, exception is erythrocytes
Contains genetic material DNA
NUCLEUS

5. Nuclear envelop: double
membrane structure, separate
cytoplasm from nucleus
Nuclear pores: Present in
membrane and function for
transport of macromolecules
across nuclear envelop
Chromatin: Impotant component,
scatered DNA, during cell
division it gets organised to
chromosomes
STRUCTURE OF NUCLEUS

6. STRUCTURE OF NUCLEUS
• Nucleolus : Prominent, dense
mass, rich in m-RNA ,store
house of m-RNA, Involved in
protein, mRNA and ribosome
synthesis
• Nucleoplasm:Fluid portion,
• Involved in vital metabolic
reactions.
• Contain various enzymes of
protein synthesis, amino acid
and lipid metabolism
Peri nuclear membrane

7. Nucleus stores hereditary material DNA.
It preserves the blue print of life in the form of genetic material.
It controls and co-ordinates activity of cell organelles
It is mainly responsible for the growth, maturation
and reproduction of organism.
It is a control centre for protein synthesis
and metabolic activity of cell
FUNCTIONS OF NUCLEUS

8.  2nd
largest organelle of cell
 Spherical, oval or rod shaped
 0.5 -- 1.0 µ diameter and 1 - 10 µ in length
 Number varies from cell to cell
 They are different as they contain their own DNA
MITOCHONDRIA
power generator

9. STRUCTURE OF MITOCHONDRIA
 Oval / Rod like body
 Bounded by two membrane
 Outer membrane smooth, most
permeable
 Inner membrane folded -- selectively
permeable
 Tightly packed inward folds are cristae
 Increases surface area
 Inner space of cristae filled – matrix

10. STRUCTURE OF MITOCHONDRIA
 Matrix contain enzymes involved in
energy metabolism of CHO, LIPID,
AMINO ACIDS.
 It take part in urea, heme and
pyrimidine synthesis
 Matrix contain circular double
stranded DNA , RNA and ribosome.
 Capable of synthesizing own
protein.
 Reproduce independently of the
cell in which it is found.

11. 1. Involved in cellular respiration.
2. Energy released from oxidation of food stuff is
trapped as ATP
3. TCA, β-Oxidation, Ketone body metabolism, urea
synthesis, heme and pyrimidine synthesis.
4. Generation of reducing equivalents (NADH)
FUNCTIONS MITOCHONDRIA
power house

12. ENDOPLAMIC RETICULUMENDOPLAMIC RETICULUM
Net work of inter connecting
Membrane Continuous from
perinuclear envelop to
outer plasma membrane.
Very prominent in the cell
Which are actively synthesizing
Proteins
Two types
1] rough endoplasmic reticulum
2] Smooth endoplasmic reticulum

13. Rough endoplasmic reticulum
Coated with ribosomes.
Gives granular appearance.
They form small vesicles called
Microsomes.
Actively involved in
protein synthesis
Smooth endoplasmic reticulum
Smooth surface
absence of ribosome
Involved in the synthesis of
Lipids (TG,PL,STEROL)
And metabolism of drugs
ENDOPLAMIC RETICULUM

14. Involved in protein synthesis
Transport, modification and
Secretion of Glycoproteins and
Lipoproteins
Detoxication of various drugs
FUNCTIONS OF
ENDOPLAMIC RETICULUM

15. Golgi apparatus
 A net work of flattened smooth membrane and vesicles
 Closely associated with Endoplasmic reticulum
It has got three parts
1] Proximal or Cis
2] medial compartment
3] distal or trans compartment

16. Functions of Golgi apparatusFunctions of Golgi apparatus
1.1. The Golgi apparatus is considered more or less theThe Golgi apparatus is considered more or less the
“POST OFFICE” of the cell.“POST OFFICE” of the cell.
2.2. It handles all incoming lipids, proteins, etc., andIt handles all incoming lipids, proteins, etc., and
controls theircontrols their export after they are modifiedexport after they are modified
3.3. Also involved in membrane synthesis (Peroxisomes,Also involved in membrane synthesis (Peroxisomes,
Lysosomes )Lysosomes )

17. Functions of Golgi apparatusFunctions of Golgi apparatus
4.4. Post translation modificationPost translation modification is important for theis important for the
proper sanctioning of the proteinproper sanctioning of the protein
5.5. Newly synthesized proteins are handed over to GolgiNewly synthesized proteins are handed over to Golgi
Apparatus which catalyses the addition of CHO, lipidApparatus which catalyses the addition of CHO, lipid
and sulphate to proteinand sulphate to protein
6.6. Some proteins are packed in membranes vesicle andSome proteins are packed in membranes vesicle and
secreted after proper signalsecreted after proper signal

18. LYSOSOMES
Suicide bags
 Spherical vesicles enveloped by single
membrane
 Regarded as digestive tract of the cell
 Involved in digestion of cellular substances
 Matrix is highly acidic pH < 5.0
Founded in macrophages

19. LYSOSOMES
Suicide bags
 Contain variety of hydrolase and degradative
types of enzymes
 EX: Glucosidase (Glycogen)
 Cathepasin (Protein)
 Lipases (Lipids)
 Ribonuclease (RNA)
Lysosomal enzymes are protein in nature and
synthesized in ER

20. Lysosomes

21. Functions of Lysosomes
1. Degradation of unwanted substances inside the cell
2. As well any external harmful material like bacteria or
virus
3. Function again vary according to the tissue in which it
is present

22. Diseases associated with malfunction of
Lysosomes
• There are a number of illnesses that are caused by the malfunction of the
Lysosomes or one of their digestive enzymes,
e.g., Pompe’s disease (GSD-II, 1-4 glucosidase)
• Tay-sachs disease, accumulation of gangliosides GM2
• caused by a defective or missing digestive enzymes,
• It leads to the accumulation of substrates within the cell,
• resulting in impaired cell metabolism.
• This disorders are broadly classified as
• mucopolysaccharidoses,
• GM2gangliosidoses,
• Lipid storage disorders,
• Glycoproteinoses,
• mucolipidoses, or
• leukodystophies.

23. Peroxisome
• Peroxisomes are ubiquitous organelles in eukaryotes
• Occur largely in hepatic and renal cell.
• They are a single membrane bound sacs.
• It separates their contents from the cytosol.
• Contain characteristic enzymes like peroxidase,
• catalase, and urate oxidase.
• It contains membrane proteins critical for various functions,
• such as importing proteins into the organelles and aiding in
proliferation.

24. • They function to get rid of toxic substances from
the cell.
• Provide protection against oxygen toxicity.
• Regulates between NAD/NADH ratio in the cell.
• Absence of peroxisome– long chain fatty acid can
not be oxidised
• Result – Zellweger syndrome (cerebrohepatorenal
syndrome)
Functions of Peroxisome

25. Cytosol • Least complex in structure but
Most complicated in chemistry.
• It is organelles less cell
• No definite structure
• Homogenous aqueous gel like
solution of protein, several
enzymes salt and metabolites.
• It contains net-work of protein
filaments
• Responsible for structure, shape
and organization of the cell

27. CELL MEMBRANE

28. CELL MEMBRANE (PLASMALEMMA)
The cell structure that separates inner from outer environments.
It is comprised of phospholipid and protein molecules
Functions as a
semi-permeable
barrier.
Allows very few
molecules across it
while fencing the
majority of
organically
produced
chemicals inside
the cell.

29. CELL MEMBRANE STRUCTURE
Fluid Mosaic Model
fluid or flexible
lipid & protein molecules
are free to move
within membrane.
molecules or large sections of membrane can easily be added or
removed molecules
mosaic – design made of inlaid work
different types of proteins built into lipid bilayer gives the
appearance.

30.  It is composed of a lipid bilayer.
 The most common molecule in the model is the phospholipid,
 Which has a polar (hydrophilic) head and
 Two non-polar (hydrophobic) tails.
 They are aligned tail to tail
 Cholesterol fills up the gap at certain places
CELL MEMBRANE –structure-lipids

31. CELL MEMBRANE structure-- proteins
•Proteins (structural types)
•Some proteins simply adhere to the membrane named
•extrinsic or peripheral proteins,
•Others reside within it or completely span it named
•intrinsic proteins or integral membrane protein.
The cholesterol molecules
Are Scattered in the bilayer

32. CELL MEMBRANE structure-- proteins
Proteins (Functional Types)
Channels: hollow passageway; may be gated (can open or close);
No cellular energy needed to open channel or pass through if open
Carriers: hollow passageway;
molecule that travels
through must attach to
carrier along passage
Eg. receptors, enzymes.

33. Complex carbohydrates are attached to protein or lipid molecules.
polysaccharide region face outward on cellular membrane.
Have highly branched, 3-D shapes; > 35,000 variations are
found
Glycoprotein & Glycolipid in cell membrane
Functions
Act as receptor
sites
to identify foreign
substances
Bind to hormones,
neurotransmitters &
other incoming
chemical signal

34. FUNCTIONS
OF
CELL MEMBRANE
1. It attaches parts of the cytoskeleton to the cell
membrane in order to provide shape.
2. It attaches cells to an extra-cellular matrix in grouping
cells together to form tissues.
3. It transports molecules into and out of cells by such
methods as ion pumps, channel proteins and carrier
proteins.

35. FUNCTIONS
OF
CELL MEMBRANE
4. It acts as receptor for the various chemical messages
which pass between cells such as nerve impulses and
hormone activity.
5. It takes part in enzyme activity which can be important in
the metabolism or as part of the body's defense
mechanism.

36. FUNCTIONS
OF
CELL MEMBRANE
• Barrier - gives shape, protection
• Selective Permeability - semi-permeable, unwanted chem.
can't enter
• Receptor Sites - cell recognition, acquire needed chemicals
• Enzymes - catalyze some cellular reactions

37. Essential Biological Functions of
cell membrane are:
1. Immune response
2. Cell metabolism
3. Neurotransmission
4. Photosynthesis
5. Cell adherence
6. Cell growth and differentiation

39. Orgenell Marker enzyme
1 Mitochondria ATP synthase – inner membrane
2 Lysosome Cathepsin – lysosomal disorder
3 GB Galactosy transferase
4 Microsome Glucose 6 phosphatase – GSD
5 Cytoplasm LDH
6 Peroxisome Catalase , Peroxidase
Marker enzymes
To identify the cell organelles in
fraction