Cambridge IGCSE Biology (0610) - IGCSE Biology - Tropic responses (14.5)

🎓 IGCSE Biology - The Complete Course: https://www.tes.com/teaching-resource/resource-12989155 IGCSE Chemistry - The Complete Course: 🎓 Complete Teaching Resource (including past exam questions and mark schemes organised by chapter): https://www.tes.com/teaching-resource/resource-13280954 🎓 Student resource (PDF only): https://www.tes.com/teaching-resource/resource-13245244 🎓 All the videos (the complete library on Patreon): https://www.patreon.com/igbiocomplete ☕️ Buy me a coffee - https://www.buymeacoffee.com/ArthurJohnParker Cambridge IGCSE Biology (0610/0970) Chapter 14 - Coordination and response Topic 14.5 - Tropic responses For exams from 2025 (core and extended) As always this video follows the Cambridge syllabus exactly and contains absolutely everything you need to know for your final exam! My other channels: @igpecomplete - Cambridge IGCSE PE @ocrpecomplete - OCR GCSE PE Timestamps: 0:00 Contents 0:30 Tropisms 0:54 Gravitropism 1:23 Phototropism 1:45 Investigating gravitropism 2:21 Investigating phototropism 2:48 The role of auxin (extended) Core content: - Describe gravitropism as a response in which parts of a plant grow towards or away from gravity - Describe phototropism as a response in which parts of a plant grow towards or away from the direction of the light source - Investigate and describe gravitropism and phototropism in shoots and roots Extended content: - Explain phototropism and gravitropism of a shoot as examples of the chemical control of plant growth - Explain the role of auxin in controlling shoot growth, limited to: (a) auxin is made in the shoot tip (b) auxin diffuses through the plant from the shoot tip (c) auxin is unequally distributed in response to light and gravity (d) auxin stimulates cell elongation Context: - So far in chapter 14, we've learned about the ways in which animals coordinate responses to changes in the internal and external environment, otherwise known as stimuli. In topic 14.1 we learned how the nervous system sends electrical impulses along nerve cells called neurones, from receptors in the sense organs to effectors (muscles and glands). We also covered the anatomy of the nervous system, including; the central nervous system, peripheral nervous system, sensory, relay and motor neurones. - In topic 14.2 we looked at sense organs in more detail, specifically the structure and function of the eye. - In topic 14.3 we covered the other communication system of the body, the endocrine system. We learned about the function of hormones, four specific endocrine glands and the hormones they secrete and the role of the hormone adrenaline. We also compared nervous and hormonal control.