Photosynthesis revision

Plants make food by which process?

• Chemosynthesis

• Photosynthesis

• Biosynthesis

• Analysis

Answer explanation

Plants make food by photosynthesis. 'Photo' means light, and 'Synthesis' means making, so 'Photosynthesis' means making from light.

What are the reactants in photosynthesis? (There are 2 correct options!)

• C6H12O6

• O2

• CO2

• H2O

What are the products in photosynthesis? (There are 2 correct answers!)

• O2

• C6H12O6

• H2O

• CO2

Answer explanation

The chemical equation for photosynthesis:

H2O + CO2 -> C6H12O6 + O2

blue = reactants

red = products

In photosynthesis, plants use water, which they get from the...

• soil

• air

• sun

• roots

In photosynthesis, plants use carbon dioxide, which they get from the...

• air

• roots

• sun

• water

In photosynthesis, plants use energy, which they get from the...

• roots

• water

• air

• sun

Answer explanation

The energy in sunlight is captured by a green pigment called chlorophyll, which is inside some of the cells in the leaves of plants.

(Click both options!)

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Answer explanation

Why is photosynthesis important?

Photosynthesis is crucial for our planet as it creates energy in food that supports all life on Earth. This energy, first captured by plants, passes through the food chain as organisms eat each other, ensuring the survival of many species.

Furthermore, photosynthesis is vital for maintaining the Earth's air by producing oxygen, which is essential for life. It's not just a biological process; it's essential for the foundation of our existence on this planet.

Plants store carbohydrates as...

• stroma

• glucose

• water

• starch

Answer explanation

Plants can make extra carbohydrates when it's sunny. They save these for later use, like at night or when there's not much sun, to have a backup energy supply. They keep these extra carbohydrates as starch in their cells, ready for when they need them.

Carbon dioxide diffuses into the leaf from the air. There are tiny holes in the leaf, which allow gases to diffuse in and out. These holes are called...

• chloroplasts

• stomata

• veins

• guard cells

Answer explanation

What are the correct labels for A, B, and C?

• A = vein

  B = lower epidermis

  C = stoma

• A = stoma

  B = lower epidermis

  C = palisade mesophyll

• A = cuticle

  B = palisade mesophyll

  C = vein

• A = cuticle

  B = epidermis

  C = palisade mesophyll

Answer explanation

Fun fact: The plural noun of 'stoma' is 'stomata'!