1. CHLOROPLAST
THE HOUSE OF PLANT
PHOTOSYNTHETIC MACHINERY
Presented by-
Mondalica Chaliha
MSc Biotech

2. INTRODUCTION
→ The term Chloroplast was first described
by Nehemiah Grew and Antonie
Van Leeuwenhoek.
→ “Chloro” means green while
“ Plast” means living.
→ Chlorophyll pigments present
in the chloroplast imparts the
green colour to plants.
→ Chloroplasts are present in plants
and other eukaryotic organisms that conducts photosynthesis.

3. =ORIGIN AND EVOLUTION

4. BIOGENESIS OF CHLOROPLAST

5. STRUCTURE OF CHLOROPLAST
→ They are planoconvex
lens- like structures
about 5µm diameter
and 2 to 3 µm thick.
→ The chloroplast comprise
. A double layered
Envelope
. A granular stroma
or matrix
. A lamellar system
. The Osmophilic globules called Plastoglobuli
. Chloroplast DNA

6. THEENVELOPE
→ It is composed of a system of double membranes ,each
of which is 50- 80 Å thick and has a unit membrane
structure.
→ The outer membrane is separated from the inner mem-
-brane by an intermembrane space of about 10nm.

7. STROMA
→ The stroma fills most of the volume
of the Chloroplast.
→ It contains about 50% of the protein
of Chloroplast.
→ It contains Ribosomes and DNA
molecule.

8. THYLAKOIDS
→ Consist of flattened and closed vesicles
arranged as membranous network
→It may be stacked like a neat pile of coins
forming GRANA
→There may be 40-80 grana in the matrix
of a Chloroplast.
→ Thylakoids includes light-absorbing
pigment s, a complex chain of electron
carriers, and an ATP-synthesizing apparatus

9. PLASTOGLOBULI
→ These are osmophilic bodies, lipid rich granules
in stroma

10. →Chloroplast DNA (cpDNA) - also known as plastid
DNA (ptDNA).
→ Circular double stranded DNA molecule.
→ Chloroplast genome size 120-217kb .
→ Majority of plants fall into 120-160kb. (Pelargonium
has chloroplast genome size 217kb)
CHLOROPLAST DNA

11. → Contains about 100 genes to synthesize proteins
→ cpDNA regions includes Large Single-Copy
(LSC) & Small Single-Copy (SSC) regions, and
Inverted Repeats (IRA & IRB).
→ Conifers and a group of legumes lack Inverted
Repeats.

13. SOME CHLOROPLAST CODING GENES
Gene Location Function
atpB Large single-copy region of chloroplast Beta subunit of ATP synthethase, which
functions in the synthesis of ATP via
proton translocation
rbcL Large single-copy region of chloroplast Large subunit of ribulose 1,5-bisphosphate
carboxylase/ oxygenase (RUBISCO),
which functions in the initial fixation of
carbon dioxide in the dark reactions.
matK Large single-copy region of chloroplast Maturase, which functions in splicing type
II introns from RNA transcripts
ndhF Small single-copy region of chloroplast Subunit of chloroplast NADH
dehydrogenase, which functions in
converting NADH to NAD + H+, driving
various reactions of respiration

14. FUNCTIONS OF CHLOROPLAST
→ Chloroplast is the site for photosynthesis
Light reaction → Thylakoid membranes
Dark reaction → Stroma.
→Chloroplast is the site for photorespiration.

15. Suggested Readings :
. Cell and molecular Biology – Gerald Karp
. Cell Biology – S.C.Rastogi
. Genetics- B.D.Singh
. Lehninger Principles of Biochemistry – Michael M.Cox
David L.Nelson

16. HT
Thank you