2. Introduction
The cell is the structural and functional
unit of life.
Types: TWO
Prokaryotes
• lack of well defined nucleus
• Devoid of nuclear envelop.
• possess simple structure.
• e.g. bacteria, blue green algae,
mycoplasma
Eukaryotes:
• possess a well defined nucleus
• Have nuclear envelop
• more complex in their structure
• e.g. animals and plants.
5. 1. Cell membrane
Fluid and mosaic model ( Singer & Nicolson)
• phospholipid bilayer
• Protein floating on it
• Cholesterol
• Small amount of carbohydrates
• Glycoprotein & glycolipid
Function
• Separates cell from
external environment
• Protects cell
• Insulating property
• Forms framework
• Has selective
permeability
• Receptor site for signal
6. 2.Mitochondria: ATP mill / power house of cell
• Spherical ,oval or rod like bodies (
0.5-1 µm X 7 µm)
• Double membrane
• 1-100 per cell
• Inner membrane fold into finger
like projection: cristae
• Absent in RBC
Functions
• Electron Transport Chain: ATP
• Krebs cycle
• β oxidation of fatty acid
• Gluconeogenesis
7. 3.Nucleus: Control center of cell
• Bcoz: Contain DNA chemical basis of
gene govern all function of cell.
• Largest & Spherical in shape
• Most prominent cell organelle
Double membrane.
• Inner membrane has nuclear pores of 90 nm free
passage
• Outer membrane is continuous with endoplasmic
reticulum
• In side it, nucleolus : RNA processing &
ribosome synthesis
Function
• DNA replication & RNA synthesis
• Home for chromosome
nucleolus
8. 4.Ribosome ( Engine of cell)
Smallest and highest in number
Protein factory
Ribonucleic protein ( RNA + protein)
Structure
• some free in cytoplasm
• some attached to ER
• 70s(prokaryote) & 80s(eukaryote)
• Have two subunits (large & small)
• 70s: 50s + 30s, 80s: 60s + 40s
Function
• Read instructions to build proteins
from mRNA
• protein factories
9. 5.Endoplasmic Reticulum
• The network of membrane or tubules
extended throughout cytoplasm.
• from nucleus to plasma membrane
• Types
• Rough ER
• Smooth ER
10. 6.Golgi bodies “ sorting sites”
Cluster of membrane vesicles
Appears like : Stacks of flattened sacs
Function:
• Receive and modify protein made by rough ER
• protein packaging, modify protein & secretion
• glycosylation and sulfation of protein
Vesicle fuses with plasma membrane
protein is released by exocytosis
E.g. pancreatic enzymes & insulin
14. 8.Peroxisomes
Are single membrane and have granular matrix.
Spherical and oval in shape
Imp: TWO enzymes
catalase
peroxidase
Function
Protects the cell from free radicals and antioxidant.
Also involved in oxidation of long chain fatty acids(>C18),
15. 9.Cytosol and cytoskeleton
The cellular matrix is aqueous gel like medium cytosol.
Consist of several enzymes , metabolites and salts.
Place for: glycolysis, protein synthesis, glycogen metabolism, HMP shunt
pathway etc.
Cytoskeleton
Cytoplasm actually contains a complex of protein filaments.
3 types-
microtubules,
actin filaments
intermediate filaments.
Role in
cell morphology,
intracellular transport,
cell motility,
cell division ( centrioles)
16. cell membrane
cell boundary
controls movement
of materials in & out
recognizes signals
cytoplasm
jelly-like material holding
organelles in place
mitochondria
make ATP energy
from sugar + O2
nucleus
protects DNA
controls cell
ribosomes
builds proteins
ER
helps finish proteins
makes membranes
Golgi apparatus
finishes, packages
& ships proteins
lysosome
food digestion
garbage disposal &
recyclingvacuole & vesicles
transport inside cells
storage
centrioles
cell division
