Difference Between Chlorophyll and Chloroplast

The difference between chlorophyll and chloroplast is due to the following factors like location and involvement in photosynthesis.
Existence: Chlorophylls exist as the primary photosynthetic pigments inside the chloroplast. Conversely, chloroplasts exist as the photosynthetic cell organelles in a plant cell and possess a membranous structure that resembles mitochondria.

Involvement in photosynthesis: Chlorophyll mainly absorbs blue and red light energy from the sun and converts it into chemical energy, whereas chloroplast serves as a site where photosynthesis occurs.

To get the idea of chlorophyll and chloroplast involvement in the photosynthetic activity of a plant system, let us suppose:

• Chloroplast acts as a unit where food is produced and stored.
• Chlorophyll acts as the workers which prepare products by the assistance of sunlight.
• Consider sunlight as a fuel that provides a natural energy source to the chlorophyll for food production.
• And, carbon dioxide and water serve the raw materials in food preparation.

Content: Chlorophyll Vs Chloroplast

1. Comparison Chart
2. Definition
3. Key Differences
4. Similarities
5. Conclusion

Comparison Chart

Properties	Chlorophyll	Chloroplast
Definition	Chlorophyll refers to the green photosynthetic pigment that participates in the photosynthetic activity of the plants	Chloroplast refers to the green membranous structure that provides the site for the photosynthetic activity
DNA	It lacks DNA	Chloroplast contains its own DNA (cp-DNA)
Location	It is located within the stacks-like thylakoid of the chloroplast	It is located within mesophyll cells of the leaves
Types	Basically of five types, but chlorophyll-a and b are the two major groups	Chloroplast is a type of plastid and not classified into any groups
Functional role	It performs a functional role in conversion of absorbed light energy to chemical energy by preparing organic food for a plant	It performs a functional role in providing space and enzymes during the light and dark reaction of photosynthesis
Imparts colour	It imparts an intense green colour to the chloroplasts	It is responsible for the green colouration of the leaves
Occurrence	It is ubiquitous in plants, cyanobacteria and algae	It is ubiquitous in plants and algae
Structure	Its structure consists of central magnesium atom, tetrapyrrole ring and a side phytol chain	Its structure consists of outer membrane, intercellular space, outer membrane and specialized thylakoid membrane
Identifying feature	It is a plant pigment	It is a cell organelle

Definition of Chlorophyll

Chlorophyll refers to the primary pigment produced by the plants, which directs photosynthesis to prepare food. It functions by absorbing the light energy (sunlight) and storing the chemical energy (ATP and NADH) to perform cellular functions. Plants use chlorophyll pigments to convert the absorbed light energy and carbon dioxide into chemical energy as organic food (carbohydrate). Its occurrence is ubiquitous in all photosynthetic organisms like higher plants, protists etc.

The location of chlorophyll is within the stack-like thylakoids. Generally, there are five kinds of chlorophyll, namely chl-a, chl-b, chl-c, chl-d and chl-f. Among all the types, chl-a and chl-b are the major groups that primarily take part in both light and dark reactions of the plant. The chemical structure of chlorophyll consists of the following elements:

• Central magnesium atom
• Porphyrin ring
• Phytol side chain

The different groups of chlorophyll vary in their chemical composition in having similar central atom and porphyrin ring but different side chain. Chlorophyll is a fat-soluble organic molecule. Its chemical structure is more or less identical to the chemical structure of haemoglobin (oxygen-carrying pigment). Chlorophylls are also considered magnesium chlorins or tetrapyrrole pigments or chlorin pigments as they have tetrapyrrole ring.

Functions: Chlorophyll performs the following tasks:

• It imparts green colour to the plants by absorbing light radiations.
• Besides photosynthesis, chlorophyll also protects plants against oxidative stress and UV damage.

Definition of Chloroplast

Chloroplasts refer to the membranous structures located within the mesophyll cells and concentrated by the parenchymatous cells in the leaves. Chloroplast occurs as a site of photosynthetic activity by the plants. Its structure looks similar to the mitochondrial membrane by having:

Outer smooth layer: It imports the nuclear-encoded proteins, and acts as a site for the biosynthesis of lipids and provides a physical barrier for the movement of molecules or ions.
Inner smooth membrane: It helps in synthesizing different metabolites and the cell division of cell organelles.
Intermembrane space: It represents the middle space between the chloroplast’s smooth outer and inner layer, whose diameter is about 10-20 nm.

Besides, chloroplast contains an internal thylakoid membrane. It possesses several specialized stack-like structures called “grana” surrounded by aqueous stroma and connected by stroma lamellae.

Functions: Chloroplast performs the following tasks:

• It is solely involved in the photosynthesis process of plants.
• Chloroplast generates metabolic energy for the plant.
• It also functions in the storage of food.

Similarities

1. Both are involved in the photosynthetic activity of a plant.
2. Chlorophylls and chloroplasts are present in higher plants and algae.
3. Both appear green-coloured.

Conclusion

Therefore, we can conclude that both the chlorophyll and chloroplasts are essential for many reasons, like:

• The green colour of the leaf.
• Splitting of water and CO₂ into glucose and oxygen or in the photosynthetic activity by a plant.

Both play their unique role in a plant cell and works together by helping plant in many ways.