Chiorophyill and are found in parts exposed to light and occur in great number in green leaves. They manufacture food material in the presence of sunlight by the help of CO, and water. Chloroplasts contain their own DNA and RNA. 

({c) Chromoplasts: These are the coloured plastids which are mostly present in the 

petais of flowers and fruits. Due to the presence of plastids the petals of flowers become showy and attractive to invite insects for pollination. The plastids may 

be yellow, orange or red because of the presence of xanthophyll (yellow) and carotene (orange red). They may also show other colours. 

Proplastids: 

These are colourless, immature plastids found in meristematic tissues where division of cells takes place. In these plastids granular stroma is present and on their outer side 

double membrane is present. In mature cells the proplastids are changed into either chioroplasts, chromoplasts or leucoplasts 

Chloroplasts as energy saving organellas 

chloroplasts are present. It is bounded by double membrane. Each chloroplast consists of three parts. 

Chloroplast is a chlorophyll containing organelle. In each photosynthetic cell 15-20 ()} A surrounding double membrane. (ii) A liquid called stroma that is enclosed by double membrane. It contains soluble proteins. It has enzymes which catalyze the dark reactions of photosynthesis. Gh) A set of flattened sac-like structures, called Thylakoids that are embedded in the stroma. 

‘Re chloroplasts convert sunlight (solar energy) into chemical or food energy by pris 

ynthesis, so the chloroplasts are the site of photosynthesis. The chloroplasts Ptuce sunlight during photosynthesis and transfer it to other molecules present in thyllokoid membrane These molecules transfer this energy to ATP (Adenosine triphosphate) and other energy carrier molecules. These are diffused into stroma. This energy Is utilized in the formation of sugar compounds by the combination of CO... in this 

way chloroplasts are considered as energy converting organella. 

(vi) Peroxisome: These are very small bodies surrounded by single membrane. The peroxisome 

secrete enzyme which transfers Hydrogen atom to Oxygen to form hydrogen peroxide (H,O,). It is a toxic compound which is immediately converted into water by catalase 

enzyme. Peroxisomes are found in the cells, which metabolize alcohol, for example in liver 

and kidney cells. They take part to destroy the toxic effect of alcohol. 

Peroxisomes also produce other enzymes such as peroxidase, glycolic acidokidase etc. The peroxisomes are also present in yeast, protozoa and many cells of higher plants. In plants they take part in catabolic and anabolic processes. 

(vii) Glyoxysomes: These are microbodies, covered by single membrane. These are usually found in 

plant cells; The glyoxysomes secrete enzymes which take part to activate the molecules of photosynthesis and respiration by fatty acid oxidation, especially in seedlings. They secrete enzymes, which metabolize the oxidation of stored fatty acids to provide energy for the formation of a new plant. These organella are produced only for a short period #7 

the germination of lipid containing seeds. (viii) Cytoskeleton: This is a network of fibrous protein, found in three-dimensional structure, fills “ 

cytoplasm of a cell. Cytoskeleton helps incell division, mitosis, meiosis, cytokinesis, wall formation; It also maintains the cell shape and differentiation of cells to form different 

parts.