The document summarizes key differences between prokaryotic and eukaryotic cells. Prokaryotic cells, which lack a nucleus, are typically smaller than eukaryotic cells and do not have internal subcellular structures like organelles. In contrast, eukaryotic cells have a well-defined nucleus that contains DNA, as well as distinct organelles such as mitochondria and lysosomes that carry out specialized functions. The document also provides details on the structure and functions of various eukaryotic cell organelles.
3. Basic structural and functional unit of life
Understanding of cell morphology is critical
to the study of biochemistry.
Divided and classified in many ways.
One common classification method is
absence or presence of a cell nucleus.
4. Prokaryotes – have no nucleus
Eukaryotes – have a nucleus
6. Organised structures in the cell.
Enclosed by plasma membrane with in the
cytosol.
All organelle have specific functions.
Plasma membrane has highly selective
permeability;
Entry and exit of compounds is regulated.
7.
8. Most prominent organelle of cell
All cells except mature RBCs in circulation
Occupies most of the available space
e.g.small lymphocytes and spermatozoa
Two membranes-outer membrane continuous
with membrane of ER, inner one is
perinuclear membrane with numerous pores.
Nucleus contains DNA-chemical basis of
genes governs all the functions of cells
Long DNA molecules complexed with proteins
to form chromatin-organised into
chromosomes
9. DNA replication & RNA synthesis
(transcription) are taking place inside the
nucleus.
Lighter shaded area of the nucleus is
neucleolus,area for RNA processing &
Ribosome synthesis
Very prominent in cells actively synthesising
proteins.
10. George palade-1974
Network of interconnecting membranes
enclosing channels or cisternae
Continuous from perinuclear envelope to
outer plasma membrane
Prominent in cells actively synthesising
Proteins ,glycoproteins,lipoproteins.
Function: detoxification of various
drugs:microsomal cytP450 hydroxylation of
benzpyrine, aminopyrine,morphine ,etc.
cholesterol synthesis(partial)
11. Electron microscopic appearance
Rough ER-ribosomes attached to cytoplasmic
side of membrane –where protiens are
synthesised
Smooth ER-no ribosomes attached
Cells are fractionated –complex ER is
disrupted –reassembled to form microsomes.
12. Camillo Golgi-1906
Network of flattened smooth membranes and
vesicles.
Converging area of ER.
While moving through ER CHTgroups are
added to nascent proteins-glycoproteins
reach the golgi area.
Function: protein sorting
packaging & secretion
13.
14. Finished products have following destinations:
Pass through plasma membrane to surrounding
medium-continuous secretion eg:secretion of
immunoglobulins by plasma cells.
Reach plama membrane form integral part-
but not secreted.
Secretory vesicles formed-stored for long time –
secreted under appropriate stimuli.
eg:trypsinogen by pancreatic cells
insulin by beta cells of langerhans.
synthesised materials collected into
lysosome packets.
18. Granular matrix
0.3 -1.5mm in diameter
Peroxidases and catalase
Prominent in leucocytes and platelets
Peroxidation of PUFA in vivo leads to hydro
peroxide formation
Deficiency:adreno-leuco dystrophy(Brown –
schilder’s disease)
insufficient oxidation of VLCFA
Zellweger syndrome-peroxisomal ghosts
Primary hyperoxaluria
19.
20. Spherical ,oval or rod like bodies
0.5 -1um in diameter;7um in length
Absent in erythrocytes
Fully packed in tail of spermatozoa
Power house of cell
Two membranes-inner convolutes into folds
or cristae
contains enzymes of ETC
Cyt.p450 system-steroidogenesis
21. Functions:
ETC
ATP generation
TCA cycle; beta oxidation of FA
Ketone body production
A part of urea synthesis ,heme
synthesis,pyrimidine synthesis
A part of gluconeogenesis
22. Microtubules –tubulin.
Role in mitosis.
Microfilaments –actin-generation of forces
for internal cell motion.
Microtrabaculae –slender fragile tubes.
23. Protein synthesis
Glycolysis
Glycogen metabolism
HMP shunt pathway
Fatty acid synthesis
Cholesterol synthesis
Purine synthesis
A part of heme synthesis,urea
synthesis,pyrimidine synthesis
24. Large organelle, without specific shape
Store waste or raw materials used in
synthesis of proteins
25. Some enzymes are present in certain
organelles only-marker enzymes
Albert Claude -1974-fractionating subcellular
organelles by applying centrifugal forces
After centrifugation –seperated organelles
are identified by detection of marker
enzymes
27. Characteristic Prokaryotic Cell Eukaryotic Cell
1.Size Small(generally 1-10µm) Large(generally 10-100µm)
2.Cell
membrane
Cell is enveloped by a rigid cell
wall
Cell is enveloped by a flexible
plasma membrane
3.Sub-cellular
organelles
Absent Distinct organelles are found (e.g
mitochondria, nucleus,
lysosomes)
4.Nucleus Not well defined; DNA is found
as nucleoid, histones are absent
Nucleus is well defined,
surrounded by a membrane; DNA
is associated with histones
5.Energy
metabolism
Mitochondria absent, enzymes
of energy metabolism bound to
membrane
Enzymes of energy metabolism
are located in mitochondria
6.Cell division Usually fission and no mitosis Mitosis
7.Cytoplasm Organelles and cytoskeleton
absent
Contains Organelles and
cytoskeleton (a network of
tubules & filaments)