1. 1. 10. Plastids Chloroplast Amyloplast Leucoplast Chromoplast
(from greek plastikos: “molded”)
Chloroplast
Amyloplast
Leucoplast
Chromoplast

2. Rapid Changes in plastid shape
Fig 1-43 Light micrograph of plastids
with thin, tubular stromule extensions

3. All plastids are developmentally related to proplastids
Plastid developmental cycle and the inter-conversion of various plastid types

4. Fig. 1-45. TEM showing a proplastid (left) adjacent to a mitochondrion
in a bean root cell

5. TEM illustrating phytoferritin deposits inside a proplastid
in a root apical meristem cell of soybean

6. 2) Amyloplasts are starch-storing plastids
: Unpigmented plastids that resemble proplastids
but contain strach granules.

7. S: starch granules
TEM of amyloplasts containing many starch granules (S)

8. 3) Several categories of plastid are named for their color
- Leucoplast are colorless plastids involved in
the synthesis of monoterpenes, the volatile compounds

9. TEM showing leucoplasts (L) in
an active secreting glandular trichome of pepperment.

10. Etioplast TEM of an etioplast PR: large prolamellar body
T: associated unstacked thylakoids
EN: envelope membrane

11. An early stage of grana thylakoid development in a greening etioplastPR
An early stage of grana thylakoid development in a greening etioplast
PR: prolamellar body

12. Chloroplasts
GT: grana thylakoids
ST: stroma thylakoids

13. Chromoplast (yellow, orange, or red….)
TEM of chromoplast of a ripe fruit of Jerusalem cherry.
The dense bodies in the plastid contain carotenoids (or xanthophylls)

14. 4) The outer and inner membrane of the plastid envelope
differ in composition, structure and transporter functions
Rich in galactolipids, poor in phopholipids
Out memebrane: nonspecific pore protein
pass size : 10 kd
Inner membrane: specific transporters
pass small uncharged

15. 5) The photosynthetic grana and stroma thylakoid membranes
form a physically continuous three-demensional network

16. TEM depicting a single granum and associated stroma thylakoids

17. The spatial relationship between stacked granna
and interconnecting stroma thylakoids

18. TEM revealing difference in grana and stroma thylakoids
PS II
PS I and
ATP synthase
TEM revealing difference in grana and stroma thylakoids

20. 6) Plastids are partially autonomous, encoding and
synthesizing some of their own proteins

21. 7) Plastids reproduced by division of existing plastids
TEM of dividing etioplast

22. 8) Plastids are inherited maternally in most flowering plants
but paternally in gymnosperms

23. 9) Plastids synthesize chlorophylls, cartenoids
and fatty acids and reduce some inorganic nutrients

24. Mitochondria
: contain the respiratory machinery that generates ATP

25. TEM of a mitochondrion in a bean root tip cell

26. Similarity in the basic architecture of all mitochondria reflects
the university of their mechanism for generating energy

27. An unusual phopholipid component of inner mitochondrial membrane

28. TEM depicting a longitudinal section through a transfer cell mitochondria
Arrows indicate ribosomes

29. 2) Small solutes cross the outer and inner mitochondrial membranes sequencially,
whereas large proteins destined for matrix cross both membrane simultaneously

30. 3) Mitochondria resemble prokaryotes in numerous important properties.
Mitochondria possess the genetic capacity to make some of
their own proteins.
Mitochondrial ribosomes resemble those of prokaryotes.
Mitochondria reproduce by fission.

31. TEM of a mitochondrion in a bean root tip cell,
showing the final phase of division

32. 4) Like plastids, mitochondria are semiautonomous and possess
the genetic machinery to make some of their own proteins
Distinctive features of plant mitochondria genome
1. large size and complexity
(about 10 fold larger than animal ones)
2. Genome: do not contain a set of tRNA genes
(16 tRNAs specific to amino acids)
3. Contains some chloroplast DNA sequences
(tRNA genes, but not functional)