Question

A chloroplast has four principal structures that play a role in photosynthesis. Choose those four structures below.

		grana
		stroma
		chlorophyll
		lamellas
		lysosomes
		thylakoids
		mitochondria

Answer 1

Grana, stroma, lamella, thylakoids

Photosynthesis is the process of formation of glucose from carbon dioxide and water molecules in the presence of Sunlight and chlorophyll. It is divided into two stages, light reaction which occurs in thylakoid membrane and the dark reaction which occurs in stroma of chloroplast.

In light reaction, the electron and chlorophyll molecules get excited in the presence of Sunlight and undergoes a series of reaction by photosystem 1 and photosystem II which leads to the formation of ATP and high energy electron carrier NADPH.

In dark reaction, the ATP and NADPH produced in light reaction are used to make glucose from carbon dioxide and water. Glucose is an energy source for plants.

The electron transport chain which occurs photosynthesis to form ATP from high energy electron carrier NADPG, takes place across thylakoid membrane. The protons generated are transferred from lumen of thylakoid to chloroplast stroma.

Grana is the stack of thylakoids arranged parallel to each other. Each grana is connected to the other with the help of lamellas. The function of grana and lamellae is to maximize the light capturing ability of thylakoids. Both photosystem 1 and photosystem 2 are present in the thylakoid membrane.

In this way the four principles structure of chloroplast are involved in photosynthesis.

You may think that chlorophyll is also involved, but the question is asking about the structures of chloroplast and not the molecules of chloroplast.

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