Chromoplasts: Characteristics, Types & Functions

Ans. No, leucoplasts do not have any color. They are colorless plastids. Leucoplasts do not contain any pigments. They contain uniform granular stroma and nucleoids. They store fat, starch, and proteins.

Ans. Plastids are heterogeneous membrane-bound organelles. They are largely responsible for the production and storage of food resources in algal and plant cells. Based on the unique role of the cell, all plastids grow from proplastids in the plant cell and mature into their respective developed plastids. Mature plastids are also capable of converting from one form to another. Some of the organisms that do not contain plastids are Blue-green algae, Fungi, Bacteria. 

Ans. Chromoplast helps to determine which pollinators visit each species of bloom. White blossoms attract insects, while violet and blue blooms attract bees. Butterflies prefer yellows and oranges. Because pollinators' attentions are restricted to a subset with blooms in a specific color range, an unintended consequence of these color variations must be that pollinators carry a higher percentage of pollen across comparable sorts of plants.

Ans. Some of the common features of mitochondria and plastids are:

• Both mitochondria and plastids have double-stranded DNA.
• Mitochondria and plastids, both contain 70s ribosomes.
• Both of them are double membranous cell organelles.

Ans. All the three types of plastids - Chloroplast, Chromoplast, and Leucoplast are evolved from proplastids. The plastids found in the pant or algae cells are of three types -

• Chloroplast - Chloroplast contains carotenoids and chlorophyll pigment. It plays a prominent role in photosynthesis.
• Chromoplasts - Chromoplasts contain Carotene and xanthophylls. They are responsible for the color of flowers and fruits, as well as pollination and seed dispersion.
• Leucoplasts - Leucoplasts are colourless organelles. They store diverse food items. Amyloplasts store starch, proteinoplasts store proteins, elaioplasts store fat, and so on.

Ans. The important functions of chromoplasts are:

• Chromoplasts play an important role in seed cross-pollination and dissemination, by attracting animals and insects.
• Chromoplasts behave like organelle within the cells of certain plants and algae that serve as a center for photosynthesis.
• Dietary carotenoid helps in lowering the risk of cancer and cardiovascular diseases.
• Fucoxanthin has been found to have anti-diabetic properties and is also known to help with obesity.
• Carrots contain β-carotene, which is an inactive form of vitamin A.

Ans. As fruits ripen, chloroplasts transform to chromoplasts, causing the color to change from green to red, orange, or yellow. Carotenoid pigments are responsible for the various colors in the plant body such as yellow, orange, and red seen in fruits, flowers, old leaves, roots, and so on. Plant tissue has hundreds of carotenoids, each having its own characteristic color. Carotenoids are classified into two types:

• Xanthophylls - Xanthophylls contain oxygen and are yellow in color.
• Carotenes - Carotenes do not contain oxygen and are orange in color.

Ans. The difference between chloroplasts and chromoplasts is mentioned in the table given below:

Ans. The leaves change color on falling from the plant. This is because of the loss of the green hue of chlorophyll, revealing the reds, oranges, and yellows that were present all along. Some of the important characteristics of chromoplasts are:

• Chromoplasts can originate from green chloroplasts. Chlorophyll and thylakoid membranes degrade and carotenoids accumulate. The conversion of chloroplasts to chromoplasts is quite visible during fruit ripening. 
• The production of chromoplasts is influenced by light, temperature, and nutrition.
• Chromoplasts are produced from proplastids or leucoplasts in plants such as papaya, carrot, mango, and watermelon.
• Chromoplasts have plastoglobules and carotenoid-lipoprotein substructures, which store particular carotenoid pigments and lipoprotein fibrils.
• During transformation, the plastid's DNA stays intact, while ribosomes and rRNA disappear.

Ans. Chromoplasts are divided into four kinds based on the carotenoid bearing components:

• Membranous Chromoplasts: In Membranous Chromoplasts, the carotene pigments are concentrated in about 20 concentric membranes. Examples are daffodils, Citrus sinensis– petals, tulips, etc.
• Globular Chromoplasts: Globular Chromoplasts have plastoglobuli that contain carotenoid pigments. They are located in the peripheral stroma of the plant cell. Examples are Capsicum- yellow fruits, Ranunculus repens– petals, Citrus fruit- perianth, etc.
• Crystalline Chromoplasts: In Crystalline Chromoplasts, the pure carotene is embedded in the form of crystals. Examples are Tomato fruits- lycopene, Carrot roots- β-carotene.
• Tubular Chromoplasts: In Tubular Chromoplasts, the carotenoids are located in lipoprotein tubules. Examples are hypanthium, Red fruits of capsicum, and rose.

Ans. The difference between chromoplasts, chloroplasts and leucoplasts

Ans. (A) Chromoplasts provide red, yellow, and orange to flowers and fruits. They are also found in some roots, such as carrots, and tubers, such as sweet potatoes.

(B) Yes, chromoplasts are double membrane-bound organelles. They are all classified as plastids, along with chloroplasts (responsible for photosynthesis) and leucoplasts (for starch storage).  

Ans. Tomatoes have chromoplasts in their pulp to produce the red color that attracts animals to disperse the tomato seeds, aiding the plant's reproduction and survival. The chromoplasts accumulate a specific pigment called lycopene. Lycopene is a carotenoid pigment that gives ripe tomatoes their characteristic red color. As the animals move around, the seeds pass through their digestive system and are eventually deposited elsewhere in their droppings.

Ans. The factors affecting the shape of a chromoplasts are as follows:

• Type of Pigment: The type of pigment stored in the chromoplast can affect how it crystallizes or distributes within the organelle, influencing the overall shape.
• Plant Cell Shape: The shape of the surrounding plant cell can also play a role. As chromoplasts develop within the cell, they may be constrained by the available space, leading to variations in their final form.

Ans. The similarities between chloroplast and chromoplast are as follows:

• Both chloroplasts and chromoplasts originate from proplastids. Proplastids are undifferentiated plastids found in plant meristems.
• Chloroplasts and chromoplasts are double membrane-bound organelles, meaning they have an outer and inner membrane, separating them from the cytoplasm of the plant cell. 
• While the specific pigments differ, chloroplasts and chromoplasts contain essential pigments within the plant cell.
• Chloroplasts contain chlorophyll, the primary pigment involved in photosynthesis.
• Chromoplasts contain various pigments like carotenoids (including lycopene and beta-carotene) and xanthophylls.