Question

In leaves, name the cell organelle and pigment responsible for green colour.
a) Chloroplast, Chlorophyll
b) Chromoplast, chlorophyll
c) Leucoplast, xanthophyll
d) Chloroplast, carotene

Answer 1

Hint: Leaves are vegetative parts of the plant. It is the main part responsible for the production of food for the plant. Leaves trap sunlight and thus can prepare its food. This is photosynthesis. Thus leaves are machinery to produce food. It can do this because of a green pigment present in a plastid.

Complete answer: The main difference between plant and animal cells is the presence and absence of Plastids. Plastids are small organelles that store food or pigments. The word Plastids are derived from the word 'Plastikas' which means molded or formed.

Plastids are of three types in plants.
a) Chromoplast: These are plastids that contain colored (carotenoid) pigments. Chroma means colored. These pigments are seen in flowers, fruits, etc. The main reason is to attract pollinators.
b) Chloroplast: These are green plastids as they contain green pigment chlorophyll. Chloros means green color.
c) Leucoplast: These are colorless plastids. These are found in non-green parts like roots.

The question is about the organelle responsible for green color. This is Chloroplast. The green pigment is Chlorophyll.

Hence the correct answer is option ‘a’.

Additional information:
Chloroplasts contain Grana suspended in a matrix called the stroma. These grana appear as stacks. Each granum has many thylakoids. This contains a green pigment which traps sunlight and undergo photosynthesis.

Note:The photosynthesis takes place by two reactions. Light and dark. Light reaction takes place in the presence of light and dark reactions do not require sunlight. The Light reaction produces ATP and NADP which act as assimilatory powers and are used by the dark reaction.