Plant Responses Audio SAQs .docx

Plant Responses Audio SAQs - What external factors regulate the growth of plants? A. light intensity, day length, gravity, temperature. - What is a tropism? A. a plants growth response to a stimuli. - What is phototropism? A. the plants growth response to the direction of light to ma...

Plant Responses Audio SAQs - What external factors regulate the growth of plants? A. light intensity, day length, gravity, temperature. - What is a tropism? A. a plants growth response to a stimuli. - What is phototropism? A. the plants growth response to the direction of light to maximise Photosynthesis. - What is geotropism? A. the plants growth response to gravity to ensure roots grow down for water and shoot up for photosynthesis. - What is hydrotropism? A. the plants growth response to the direction of water availability to maximise water as it is required for plant survival. - What is thigmotropism? A. a plants growth response to touch which allows vines etc to wrap themselves around trees to provide support. - What is chemotropism? A. a plants growth response to chemical signals. - What are plant growth regulators? A. chemicals that control the growth of a plant. - Where are plant growth regulators produced? A. In the meristem. - What is the combined effect? A. when the levels of plant growth regulators will interact and alter and control the growth in the correct way. - What is the function of promoters? A. To stimulate growth. - Give 1 use of a plant growth regulator. A. Ethene to ripen fruit/ auxin in weedkillers. - What do plants need to protect themselves from? A. loss of water, overheating, infection from microorganisms and being eaten by herbivores. - Give 1 example of a structural plant defence. A. Bark blocks the entry of pathogens/ stinging cells to stop animals eating the plant. - Give 1 example of a chemical plant defence. A. Tannin production to make leaves inedible/ toxic chemicals to prevent larvae development.