Biology Grade 12 Quiz: Phototropic and Geotropic Responses

What is phototropic response in plants and how does it help them?

• The growth or movement of a plant in response to light, helping them to orient themselves towards a light source for photosynthesis and overall growth.

• The response of plants to sound, helping them to communicate with other plants

• The response of plants to gravity, helping them to anchor themselves in the soil

• The response of plants to touch, helping them to avoid being eaten by herbivores

Explain the role of auxin in phototropic response in plants.

• Auxin promotes cell elongation on the shaded side of the stem, causing the stem to bend towards the light source.

• Auxin inhibits cell elongation on the shaded side of the stem, causing the stem to bend away from the light source.

• Auxin causes the stem to remain straight and not bend towards the light source.

• Auxin has no role in phototropic response in plants.

Describe the mechanism of phototropic response in plants.

• Increased production of oxygen in response to light

• Auxin hormone movement towards the shaded side of the stem

• Decreased water absorption in the roots

• Movement of chlorophyll towards the sunlight

How do plant roots exhibit geotropic response?

• By growing towards light

• By growing horizontally

• By growing away from gravity

• By growing in the direction of gravity

What is the significance of geotropic response in plant roots?

• It helps roots grow in the direction of gravity and anchor the plant.

• It helps roots grow towards light

• It causes the roots to shrink and die

• It has no significance in plant roots

Explain the difference between positive phototropism and negative geotropism.

• Positive phototropism is the growth of a plant towards light, while negative geotropism is the growth away from the force of gravity.

• Positive phototropism is the growth of a plant towards the force of gravity, while negative geotropism is the growth towards light.

• Positive phototropism is the growth of a plant away from the force of gravity, while negative geotropism is the growth towards light.

• Positive phototropism is the growth of a plant away from light, while negative geotropism is the growth towards the force of gravity.

Give an example of a plant exhibiting positive phototropism and explain the impact.

• Daisy

• Tulip

• Cactus

• Sunflower

Discuss the impact of negative geotropism in plant roots and provide an example.

• Negative geotropism in plant roots allows them to grow away from the force of gravity, enabling them to explore the soil for nutrients and water.

• Negative geotropism in plant roots causes them to grow sideways, making it difficult for them to absorb nutrients and water.

• Negative geotropism in plant roots has no impact on their ability to explore the soil for nutrients and water.

• Negative geotropism in plant roots causes them to grow towards the force of gravity, limiting their ability to explore the soil for nutrients and water.