The document discusses mitochondria and chloroplasts. It provides definitions and descriptions of their structures, functions, and genomes. Mitochondria are organelles that convert food into ATP and are involved in cell death and growth. They have outer and inner membranes that create compartments. Chloroplasts contain chlorophyll and are the sites of photosynthesis. They are bound by outer and inner membranes that create a fluid-filled interior with thylakoid membranes where light reactions occur. Both organelles have semi-autonomous genomes that interact with the cell's nuclear genome.

1. MITOCHONDRIA AND CHLOROPLAST
NAME – DEBJIT PARUI
STREAM – MSC BIOTECHNOLOGY
ROLL NO-14000214

2. MITOCHONDRIA
DEFINITION-Mitochondria are double layer
membrane-enclosed organelles distributed
through the cytosol of most eukaryotic cells.
Their main function is the conversion of the
potential energy of food molecules into ATP.
So mitochondria are also called “the
powerhouse” of the cell. In addition to
supplying cellular energy, mitochondria are
involved in cell death, as well as the control
of the cell cycle and cell growth.

3. HISTORY OF MITOCHONDRIA
 Richard Altmannin 1894, established them as cell organelles and called them
"bioblasts".
 The term "mitochondria" was coined by Carl Benda in 1898.
 Leonor Michaelis discovered Janus green can be used as a supravital stain for
mitochondria in 1900.
 In 1913 particles from extracts of guinea-pig liver were linked to respiration
by Otto Heinrich Warburg, which he called "grana".
 The first high resolution micrographs appeared in 1952, replacing the Janus
Green stains .
 The popular term "powerhouse of the cell" was coined by Philip Siekevitz in
1957

4. MORPHOLOGY
 SIZE: Mitochondria range from 0.5 to
1.0 μm in diameter.
 SHAPE: normally Sausage shaped, In
fibroblasts-elongated and thread like
 NUMBER: Depends on type size and
functional state of cell. Eg: An average
liver cells contain around 1500
mitochondria.
 LOCATION: Cells with high enrgy
requirements; Eg:Sperm tail, Muscle,
Flagella

5. MITOCHONDRIAL
STRUCTURE
 1.Outer membrane
 2. Inner membrane
 3. Inter membrane space
 4. Translocation contact site
 5.Matrix
 6. Cristae

6.  1. OUTER MEMBRANE – It contains many complexes of integral
membrane proteins that form channels through which a variety of
molecules and ions move in and out of the mitochondrion. we called it
porins. These porins form channels that allow molecules 5000 Daltons
or less in molecular weight to freely diffuse from one side of the
membrane to the other.

7. 2.INNER MEMBRANE
 The inner membrane, which encloses the matrix space, is folded to form
cristae. The area of the inner membrane is about five times as great as
the outer membrane.
 This membrane is richly endowed with cardiolipin, a phospholipid that
possesses four, rather than the usual two, fatty acyl chains. The presence
of this phospholipid in high concentration makes the inner membrane
nearly impermeable to ions, electrons, and protons.
 The inner membrane has a very high protein-to-phospholipid ratio (about
4:1 by weight).
 Impermeable to most charged molecules.

8. 3. INTER MEMBRANE SPACE – It contains several enzymes that use the ATP that passes out of the matrix
to phosphorylate other nucleotides.
4. TRANSLOCATION CONTACT SITE
 TOM(Translocon of the outer membrane)
 TIM(Translocon of the inner membrane)
Inner membrane contains three major types of proteins:
1.Those that carry out the oxidation reactions of the respiratory chain
• NADH dehydrogenase
• Cytochrome b-c1
• Cytochrome oxidase
2.ATP synthetase
3.Specific transport proteins

9. 5. MATRIX - It contains hundreds of
different enzymes including those required
for
①the oxidation of pyruvate and fatty acids
②the citric acid cycle.
It also contains small amounts of
mitochordrial DNA genome, special
mitochondrial ribosomes, tRNAs and various
enzymes that required for the expression of
the mitochondrial genes.

10. THE MITOCHONDRIAL
GENOME
 The human mitochondrion contains 5-10 identical molecules of DNA. Mitochondrial
DNA(mtDNA) are circular, double-stranded structures of molecules in higher
eukaryotes. They encode their own mRNA, rRNA and ribosomal proteins, tRNAs and a
few mitochondrial proteins.
 Each mitochondrion consists of 16’569 base pairs carrying the information for 37
genes.
 but only 13 of these code for polypeptides, the remainder being the 2 ribosomal
subunits and 22 types of transfer RNA.
 However, most of the proteins in the mitochondrion are encoded in nucleus by
nuclear DNA, synthesized in cytosol, and subsequently transported into the
mitochondrion.

11.  Because the growth and proliferation of mitochondria are controlled
by both nuclear genome and it’s own genome. Mitochondria are
usually called semiautonomous organelle.

12. CHLOROPLAST
DEFINTION -The word chloroplast is derived from the
Greek words chloros, which means green, and plastes,
which means “the one who forms”.
 Chloroplasts are a type of membrane-bound plastids
that contain a network of membranes embedded
into a liquid matrix and harbor the photosynthetic
pigment called chlorophyll.
 Chloroplasts can be found in the cells of the
mesophyll in plant leaves.
 There are usually 30-40 per mesophyll cells.

13. STRUCTURE OF
CHLOROPLASTS
The chloroplast has an inner and outer
membrane with an empty intermediate space
in between. Inside the chloroplast are stacks
of thylakoids, called grana, as well as stroma,
the dense fluid inside of the chloroplast. These
thylakoids contain the chlorophyll that is
necessary for the plant to go through
photosynthesis. The space the chlorophyll fills
is called the thylakoid space.

14. A chloroplast thus has the following parts:
1.Envelope (Outer membrane):
It is a semi-porous membrane and is
permeable to small molecules and ions,
which diffuses easily. The outer
membrane is not permeable to larger
proteins.
2.Intermembrane Space
It is usually a thin inter-membrane space about
10-20 nanometers and it is present between the
outer and the inner membrane of the chloroplast.

15. 3.INNER MEMBRANE
The inner membrane of the chloroplast forms a
border to the stroma. It regulates the passage of
materials in and out of the chloroplast. In addition
to regulation activity, fatty acids, lipids, and
carotenoids are synthesized in the inner
chloroplast membrane.
4.STROMA
Stroma is an alkaline, aqueous fluid that is protein-
rich and is present within the inner membrane of
the chloroplast. The space outside the thylakoid
space is called the stroma. The chloroplast DNA
chloroplast ribosomes and the thylakoid system,
starch granules and many proteins are found
floating around the stroma.

16. 5.Thylakoid System
The thylakoid system is suspended in the stroma. The
thylakoid system is a collection of membranous sacs
called thylakoids. The chlorophyll is found in the
thylakoids and is the sight for the process of light
reactions of photosynthesis to happen. The thylakoids
are arranged in stacks known as grana. Each granum
contains around 10-20 thylakoids.
Peripheral Reticulum: The chloroplasts of certain
plants contain an additional set of membranous tubules
called peripheral reticulum that originates from the
inner membrane of the envelope. Tiny vesicles bud off
from the inner membrane of the chloroplast and
assemble to form the tubules of the peripheral
reticulum.

17. FUNCTIONS OF CHLOROPLASTS
 Chloroplasts are the sites for photosynthesis, which
comprises a set of light-dependent and light-
independent reactions to harness solar energy and
convert it into chemical energy.
 The components of chloroplast participate in several
regulatory functions of the cell as well as in
photorespiration and Calvin cycle.
 Chloroplasts also provide diverse metabolic activities
for plant cells, including the synthesis of fatty acids,
membrane lipids, isoprenoids, tetrapyrroles, starch,
and hormones.
 Plants lack specialized immune cells—all plant cells
participate in the plant response.
 The chloroplasts with the nucleus and cell membrane
and ER are the key organelles of pathogen defense.
 Chloroplasts can serve as cellular sensors.