ISOLATION OF SUBCELLULAR ORGANELLES
Homogenizationwith help of glass/teflon homogenizer cells are
disrupted by- suspending in isotonic soln (0.25 M
buffer at pH 7.4)
Differential velocity Centrifugation.
Separation based on their size.
ISOLATION OF SUBCELLULAR ORGANELLES
Mitochondria Golgi complex
G 6 PD
Parts of the Cell
prominent and large
houses most of a
Controls the activity
of other organelles.
Structure of Nucleus
a spherical or oval-shaped structure.
Most cells have a single nucleus, although some,
such as mature RBCs, have none. In contrast,
skeletal muscle cells have multiple nuclei.
the nuclear envelope, membrane of the nuclear is
continuous with rough ER
Each nuclear pore consists of a circular
arrangement of proteins surrounding a large
1. Controls cellular structure.
2. Directs cellular activities.
3. Produces ribosomes in nucleoli.
The nuclear envelope
Details of the nucleus
Ribosomes are the sites of protein
The name of these tiny organelles
reflects their high content of rRNA.
They either attached to RER or
float freely in cytoplasm.
consists of two subunits.
- large subunit
- small subunit.
A network of membranes in
the form of flattened sacs
1. Rough ER synthesizes proteins.
2. RER involved in post-translation modifications
such as glycation.
3. SER synthesizes phospholipids, cholesterol (in
many tissue) & steroid hormones (adrenals,
4. SER is site of Glycogen metabolism.
5. Stores & releases calcium ions in the cells. (that
trigger contraction in muscle cells.)
6. In liver & Kidney SER Detoxifies drugs & harmful
7. Removes the phosphate group from G-6-P; and
release free glucose in blood.
It consists of 3 to 20 cisternae, small,
flattened membranous sacs.
Most cells have several Golgi complexes
Golgi complexes are more extensive in
cells that secrete proteins
Modifies, sorts, packages, & transports
proteins received from the rough ER
Processing and packaging of proteins by the Golgi complex.
Elongated or rod shaped.
“powerhouses” of the cell.
No. may as few as hundred
or as many as several
thousand, depending on the
activity of the cell.
Active cells such as muscles,
liver, and kidneys, which use
ATP at a high rate, have a
large number of Mitochondria
Generate ATP through reactions of
Helps in Biochemical reactions. Such
as oxidation of fatty acids, TCA, etc
Membrane-enclosed vesicles that
form from the Golgi complex.
60 kinds of powerful digestive
and hydrolytic enzymes.
Lysosomal enzymes also help
recycle worn-out cell structures.
Helps in fertilization.
Some disorders are caused by
faulty or absent lysosomal
enzymes. e.g, Niemann pick
disease, Gaucher’s disease.
Similar in structure to lysosomes, but smaller in size.
Contain several oxidases, enzymes that can oxidize
various organic substances.
Functions : Degradation of amino acids, oxidation of long chain
Oxidize toxic substances, such as alcohol.
protect other parts of the cell from the toxic effects
Dysfunction of Peroxisomes leads to Zellweger syndrome
A network of protein filaments that
extends throughout the cytoplasm.
Three types of filamentous proteins
contribute to the cytoskeleton’s structure,
Microtubules: Long, Hollow, unbranched, polar cylinders.
mead up of protein “tubulin”(α & β tubulin)
The largest of cytoskeletal components.
Microtubules help in structural support,
To maintain the shape of the cell.
Movement of organelles such as secretary vesicles,
chromosomes during cell division.
Forms mitotic spindles during mitosis.
Movement of cilia and flagella.
Disorder: Primary ciliary dyskinesia- associated with celiary dysfunction
clinical effect- recurrent upper & lower resp. tract infection,
INTERMEDIATE FILAMENTS :
Polymers of long rod like proteins.
these filaments are thicker than microfilaments
but thinner than microtubules.
Functions :Provide mechanical support to the cell.
Thinnest elements of the cytoskeleton.
Composed of the protein actin,
Most abundant intracellular protein that that
conc. Just under the plasma membrane.
Most prevalent at the edge of a cell
Mechanical support for the basic strength &
shapes of cells.
Microfilaments are involved in muscle
contraction, cell division, and cell locomotion.