Plastids are double-membrane organelles found in plant and algae cells that are responsible for important biochemical functions. There are three main types of plastids: chloroplasts, which facilitate photosynthesis; chromoplasts, which produce and store pigments; and leucoplasts, which synthesize compounds like proteins and starches. Chloroplasts have an additional internal membrane system called thylakoids that form stacks and contain chlorophyll. Chromoplasts and leucoplasts come in various subtypes depending on their contents and shape. All plastids contain a double membrane, stroma, DNA, ribosomes and other components that allow them to perform vital roles in plant cells.

1. Presented By:
Fatima Adil
Roll No:
18371514-106
Presented To:
Sir Tahir Iqbal

2. 
 Plastids are double membrane bound organelles.
 Found inside plants and algae.
 Responsible for activities related to manufacture and
storage of important chemical compounds used by the
cells .
 The types of pigments present can
determine the cell's color.
INTRODUCTION

3. 
 Pro-plastids may develop into of the following:
 Chloroplasts
 Chromoplasts
 Leucoplasts
TYPES OF PLASTIDS

4. 
CHLOROPLAST
 The chloroplasts are probably the most known of the
plastids.
 These are responsible for photosynthesis.
 Found in plant cells and other eukaryotic organisms.
 The word chloroplast is derived from the Greek words
 Chloros, which means green,
 Plast, which means entity

5. 
 Chloroplast are spheroid or ovoid or discoid in higher
plants.
 Bounded by a double membrane called the chloroplast
envelope.
 Chloroplasts have a third internal membrane system,
called the thylakoid membrane.
 Thylakoid membrane forms a network of flattened discs
called thylakoids, arranged in stacks called grana.
General structure:

6. 
 Chromoplasts are place for the pigments to be stored and
synthesized in the plant.
 Found in flowering plants, fruits, and aging leaves.
 Chloroplasts actually convert over to chromoplasts.
 There are carotenoid pigments here that allow for the
different colors.
CHROMOPLASTS

7. 
 Based on structure, chromoplast are categorized as
follow:
 Globular chromoplasts
 Crystalline chromoplasts
 Fibrillar chromoplasts
 Tubular chromoplasts
 Membranous chromoplasts.
Categories of chromoplast:

8. 
 There are two types of chromoplasts which include:
 Phaeoplast
• Brownish and naturally found in brown algae
 Rhodoplast
• Plastids found in red algae
Types of chromoplast:

9. 
 Leucoplasts are the non-pigmented organelles.
 Leucoplasts have no color at all.
 Found in the non-photosynthetic
parts of the plants,
• such as the roots.
 Used for synthesizing amino acids
and fatty acids.
LEUCOPLASTS

10. 
 Leucoplasts are further subdivided into three different
plastids:
 Amyloplasts
• are the largest of the three and are charged with storing starch.
 Proteinoplasts
• help to store the proteins that a plant needs and are typically
found in seeds.
 Elaioplasts
• are used to store fats and oils that are needed by the plant,
specifically in seeds.
Types of leucoplasts:

12. 
 Number of plastids range from 30 to 40 and 100 to 150 in
diploid cells.
 The plastids of plants are also simpler when compared to
those found in other organisms like algae.
 Depending on the species plastids take up a variety of
shapes
• e.g. discoid, spherical, dumbbell-shaped or lens-shaped
among a few others.
General Structure and Features of Plastids:

13. 
 One of the other important structures associated with
plastids is the stromule.
 Stromule plays an important role in ensuring
communication between the plastids and other cell
organelles
• such as the mitochondria and the cell nucleus.

14. 
 Double membrane is only membrane that remains intact.
 Due to genome reduction of plastids, they are only able to
encode for a small number of proteins.
 The membrane, plays an important role in
• Cell signaling
• Regulation of gene expression.
Double-Membrane

15. 
 Some of the other roles of plastid envelopes include:
 Transport of other material including vital metals and
metabolites
 Metabolism of fatty acid, lipids, and carotenoid among
other compounds
 Production of plant growth regulators
 Interaction with the cell's endomembrane systems
Cntd..

16. 
 Stroma refers to the internal space that is enclosed by the
double membrane of the plastid.
 Some of the other components of the stroma include:
 Ribosome -
• Is a major characteristic of plastid stroma.
• The presence of ribosome indicates protein synthesis
activities.
PLASTID STOMA

17. 
 Nucleoids –
• Include copies of the plastid DNA and RNA.
• Functional unit of the plastid's genome..
 Other components found in the stroma include:
 Inclusion bodies
 Microtubules
 Stromacenters
 Starch
 Plastoglobuli
Cntd..

18. 
 Found in land plants.
 Develops from the inner membrane envelope.
 Attach to the inner membrane forming a membrane system
known as the peripheral reticulum.
 This system plays role in the transport of materials from
the cytoplasm to plastid and vice versa.
INTERNAL MEMBRANE