1.
The Physiological
role of cell
organelles
Dr. Irtaza Rehman
(Author of the book The Extraordinary Life)

2.
Learning Objectives
• To understand more detail about the cell
organelles
• To understand functional importance of
different cell organelles

3.
Introduction of cell
• There are different types of cells in human body.
• Each having different structure, functions and
location.
• Each having different composition of
intracellular organelles.

4.
Types of cells

5.
Cell membrane

6.
Q. Which is the
most abundant
component of cell
membrane?
• A. Carbohydrate
• B. Cholesterol
• C. Phospholipids
• D. Proteins

7.
Q. Which is the
least abundant
component of cell
membrane?
• A. Carbohydrate
• B. Cholesterol
• C. Phospholipids
• D. Proteins

8.
Composition of cell membrane
Biomolecule Quantity
Protein 55 %
Phospholipid 25 %
Cholesterol 13 %
Other lipids 4 %
Carbohydrate 3 %

9.
Transport through cell membrane
O2
CO2
Steroid
hormones
“Because we are lipid soluble, can easily
pass through hydrophobic lipid bilayer”

10.
Transport through cell membrane
Na
Cl
Glucose
H2o

11.
Membrane Proteins

12.
Membrane Proteins
Integral protein

13.
Integral Proteins

14.
Q. Cytoskeleton
is an example of
• A. Integral protein
• B. Peripheral protein
Ans. Peripheral Protein

15.
Facts of Peripheral proteins
• Not embedded in the cell
membrane
• Not covalently bound to
membrane components
• Acts as an enzyme
• Controls membrane
transport through
membrane pores.

16.
Cell membrane lipids

17.
Cholesterol
• Determines the degree
of permeability to
water soluble
substances.
• Controls membrane
fluidity

18.
Sphingolipids
• Present in nerve cells as
sphingomyelin
• Phospholipids: glycerol
backbone –
sphingolipids:
sphingosine backbone
• Protects from harmful
environmental factors
• Signal transmission

19.
Membrane Carbohydrates

20.
Membrane Carbohydrates

21.
Membrane Carbohydrates

22.
Nucleus

23.
• Directing protein synthesis
• Serves as genetic blueprint
during cell replication
• Contains genetic
information for
reproduction,
development and behavior
Nucleus

24.
Nucleus

25.
Nucleolus
• Ribosomal RNA synthesis
• r-RNA + Proteins =
Ribosomes

26.
Chromatin

27.
Chromatin

28.
Endoplasmic reticulum

29.
• Rough E.R: Protein
synthesis
• Smooth E.R: Lipid
synthesis. Poisons/drug
detoxification.
Stores Calcium
Endoplasmic reticulum
Sends vesicles to Golgi apparatus

30.
Golgi Apparatus

31.
Golgi Apparatus
Abundantly
Found in
Glandular/
secretory cells

32.
• Packaging
center/Shipping
center
• Modification
1. Glycosylation
2. Phosphorylation
Golgi Apparatus
Buds off:
Lysosomes
Membrane proteins
Excreted

33.
Lysosome

34.
ysosomes are derived from olgi apparatus

35.
Lysosome
• Hydrolytic enzymes
(low pH: 5)
• Autophagy
• Autolysis
• Recycling

36.
Lysosome
Why? To control the # of specific organelle

37.
• Programmed cell
death
• Lysosome burst &
enzymes
dispersed in
cytoplasm
• Disintegration of
cell which is then
phagocytosed by
other cells
Lysosome
Autolysis
Suicide sacs

38.
Mitochondria

39.
Mitochondria
• Semi autonomous
(own DNA/genes)
• Independent
replication of nucleus
via binary fission
• Inner wall contains
ETC enzymes

40.
Like the
meltdown
incident, it can
also release
some of
enzymes in ETC
during
programmed
cell death
(apoptosis)

41.
Which cells have most
abundant # of
mitochondria?
A. Liver cells
B. Kidney cells
C. Skeletal Muscle cells
D. Cardiac Muscle cells
Ans. Cardiac muscle cells

42.
Peroxisome

43.
Peroxisomes
are derived
from
SER
They can
also
replicate
Abundant
in Liver

44.
Peroxisome
• Ethanol metabolism
• Production of
hydrogen peroxide
• Antioxidant
properties
• Bile acid formation
Peroxidase
Catalase

45.
Peroxisome

46.
Cytoskeleton
Transport system/Structural
strength

47.
Ans.
Ribosomes
Q. Cytoskeleton
is produced by??

48.
• 2 Actin
• 2 Tropomyosin
• +Troponin
• Muscle
Contraction/Relaxtion
• Cyclosis
Cytoskeleton
Microfilaments

49.
Microtubules
Cytoskeleton
• Centrioles
• Cilia
• Flagella

50.
• Intermediate size
• Mechanical support to
nuclear envelope and
plasma membrane
• Vimentin
Cytoskeleton
Intermediate
filaments

51.
Jazakumullahu Khair ♥
(May ALLAH swt reward you with goodness)