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 as a unit where food is produced and stored.
  • Chlorophyll as the workers those who prepare a product by the assistance of sunlight.
  • Consider sunlight as a fuel that functions to provide a natural source of energy to the chlorophyll for the food production.
  • And, carbon dioxide and water serves the raw materials in the food preparation.

Content: Chlorophyll Vs Chloroplast

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

Comparison Chart

PropertiesChlorophyllChloroplast
DefinitionChlorophyll refers to the green photosynthetic pigment that participates in the photosynthetic activity of the plantsChloroplast refers to the green membranous structure that provides the site for the photosynthetic activity
DNAIt lacks DNAChloroplast contains its own DNA (cp-DNA)
LocationIt is located within the stacks-like thylakoid of the chloroplastIt is located within mesophyll cells of the leaves
TypesBasically of five types, but chlorophyll-a and b are the two major groupsChloroplast is a type of plastid and not classified into any groups
Functional roleIt performs a functional role in conversion of absorbed light energy to chemical energy by preparing organic food for a plantIt performs a functional role in providing space and enzymes during the light and dark reaction of photosynthesis
Imparts colourIt imparts an intense green colour to the chloroplastsIt is responsible for the green colouration of the leaves
OccurrenceIt is ubiquitous in plants, cyanobacteria and algaeIt is ubiquitous in plants and algae
StructureIts structure consists of central magnesium atom, tetrapyrrole ring and a side phytol chainIts structure consists of outer membrane, intercellular space, outer membrane and specialized thylakoid membrane
Identifying featureIt is a plant pigment It is a cell organelle

Definition of Chlorophyll

Chlorophyll refers to the primary pigment produced by the plants, which directs the process of 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 in the form of organic food (carbohydrate). Its occurrence is ubiquitous in all photosynthetic organisms like higher plants, protists etc.

diagram showing chlorophyll

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 like:

  • Central magnesium atom
  • Porphyrin ring
  • Phytol side chain

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

Functions: Chlorophyll performs the following tasks like:

  • Imparts green colour to the plants by absorbing the light radiation.
  • Besides photosynthesis, chlorophyll also protects plants against oxidative stress and UV-damage.

Definition of Chloroplast

Chloroplasts refers to the membranous structures, which are 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:

Diagram showing Chloroplast

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 the synthesis of different metabolites and the cell-division of cell organelles.
Intermembrane space: It is the middle space between the smooth outer and inner layer of the chloroplast whose diameter is about 10-20 nm.

Besides, chloroplast contains an internal thylakoid membrane. It possesses several specialized stack-like structures called “grana” that are 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.

Key Differences Between Chlorophyll and Chloroplast

  1. Chlorophyll is a chlorin pigment that traps the red and blue light of the electromagnetic spectrum and transmits green light during the photosynthesis. A chloroplast is a cell organelle that acts as a site for all the photosynthetic activity by providing space and enzymes.
  2. Chlorophyll is devoid of its DNA, whereas chloroplast contains its own DNA (cp-DNA) like mitochondria.
  3. Chloroplasts exist as small reticulations within the mesophyll cells of a leaf, while chlorophylls are the plant pigments located within the thylakoids discs.
  4. Chlorophyll-a, b, c, d and f are the five groups, among which chlorophyll-a and b are the two major groups that predominate in a plant. The chloroplasts are the most common type of plastid characterized by two membranous structure with high chlorophyll content.
  5. Chlorophylls impart an intense green colour to the chloroplasts by absorbing a light wavelength (usually red and blue) of the visible light spectrum, and reflecting green.
    Chloroplast appears green because of the chlorophyll presence within the infolded thylakoids, which in turn imparts green colour to the leaves.
  6. The structure of chlorophyll comprises of a central magnesium atom, tetrapyrrole ring and a varying side chain, due to which it is also termed as “Magnesium tetrapyrrole pigments”.
    Chloroplast structure mainly comprises of two membranes (outer and inner), specialized thylakoid membrane and intercellular space within the outer and inner layer.

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 appears green-coloured.

Conclusion

Therefore, we can conclude that both the chlorophylsl 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.

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