Photosynthesis: 17 MCQs with answers

To produce food (glucose) using sunlight

Photosynthesis is the process by which plants make their own food (glucose) using sunlight, carbon dioxide, and water.

Carbon dioxide

Plants absorb carbon dioxide from the air through small openings called stomata.

Sunlight

Sunlight provides the energy needed to drive the chemical reactions of photosynthesis.

It is released into the atmosphere

Oxygen is released as a byproduct into the atmosphere through the stomata.

It provides energy to split water molecules

Sunlight provides the energy needed to drive the light-dependent reactions, including the splitting of water.

Ferns

Ferns are plants and contain chlorophyll, so they can perform photosynthesis.

True

Sunlight is essential for the light-dependent reactions of photosynthesis.

False

Plants respire continuously, both day and night, to release energy from glucose.

Chlorophyll

Chlorophyll is the green pigment that absorbs light energy, primarily in the chloroplasts of plant cells.

Glucose and oxygen

Photosynthesis produces glucose (food) and oxygen as a byproduct.

Chloroplast

Chloroplasts contain chlorophyll and are the site of photosynthesis.

Oxygen

Oxygen is a product of photosynthesis, not a requirement. The requirements are sunlight, carbon dioxide, and water.

It provides electrons and hydrogen ions

Water is split during the light-dependent reactions to provide electrons, hydrogen ions, and oxygen.

Stomata

Stomata are small pores on the leaf surface that allow carbon dioxide to enter and oxygen to exit.

To provide energy for the plant's life processes

Glucose is used by the plant as a source of energy and as a building block for other organic molecules.

$6CO_2 + 6H_2O \rightarrow C_6H_{12}O_6 + 6O_2$

The balanced equation for photosynthesis is $6CO_2 + 6H_2O \rightarrow C_6H_{12}O_6 + 6O_2$.

ATP and NADPH

The light-dependent reactions produce ATP and NADPH, which are used in the Calvin cycle to make glucose.