AQA A Level Biology: Gas Exchange скачать в хорошем качестве

AQA A Level Biology: Gas Exchange

Unlock full course: https://studymind.co.uk/online-course... Today you’re going to learn about Exchange Between Organisms in particular Gas Exchange from the A-Level Biology AQA Specification and feel confident about exam technique! ✅ Watch all the videos for FREE on https://bit.ly/32OAe7d alongside our textbook and free flashcards. A-Level Biology especially for AQA can be tough but fortunately we’ve made this tutorial to help you score the A* you need for questions on Gas Exchange. ✅ 📒The three main aims of this tutorial are to cover: 📒 1. Gas Exchange in Fish, Plants, Insects and Humans 2. Structure and Function of Respiratory Organs 3. Pathologies of the Human respiratory System Gas Exchanges in Unicellular Organisms (2:02) In unicellular organisms, gas exchanges occur via the cell membrane. Gas exchanges across membranes are carried out through simple diffusion. Gas Exchanges in Insects (3:23) Most insects are land organisms with a tough exoskeleton. Exoskeletons are too thick for gas exchange. Gas exchanges in insects occur via the tracheal system. Pathway of Oxygen in Tracheal System (3:56) Air enters into the body of insects through spiracles. Spiracles transfer the air to thin tubes called the tracheae. The tracheal system contains a special fluid for carrying oxygen. Gas Exchange in Plant Leaves (6:32) Mesophyll cells are on the surface of plant leaves. Gas exchange in the leaves occurs through the stomata on the lower epidermis. The opening and closing of stoma is regulated by guard cells. In plant leaves, approximately 50% of the volume is air space. Unlike other organisms, plants are reliant on both oxygen and carbon dioxide. Water Loss in Plants (8:54) Water is stored in leaves. Water can be lost in a plant through transpiration. There is a balance between gas exchange and water loss. Plants have some adaptations to strike the best balance: Position of stomata, cuticle, guard cells. Stomata open when water supply is good: Stomata close at night. Xerophytic Plants (11:24) Xerophytic plants are adapted to hot, dry environments. Xerophytes need to minimise transpiration. Xerophytes have developed several adaptations to survive. Water Loss in Insects (13:13) Insects have some adaptations to reduce water loss: Spiracles - specialised muscles can close spiracles to prevent water loss. Hairs on spiracles - hairs on spiracles trap a layer of moist air. Thick waxy cuticle - similar to plants, insects have a thick cuticle to prevent water loss. Summary of video To catch our latest videos, subscribe and leave a comment below on a video you’d like us to record! 👇 Subscribe to Study Mind with ONE CLICK👇 👇Revise with free past papers BY TOPIC for AQA A-Level Biology👇 https://bit.ly/2mE065v 👇Get personalised 1-1 Tutoring at £30ph for GUARANTEED improvement👇 https://bit.ly/2mDXNzn Tags: #AQABiology #ALevelBiology #StudyMind GasExchange