16638982
Description
Flashcards by Sea Chel Pie, updated more than 1 year ago
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Created by Sea Chel Pie
over 5 years ago
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| Question | Answer |
| how are Single-celled organisms adapted ? | ~ Small -> Large SA:V ratio ~ O₂ absorbed by DIffusion -> across body surface by cell-surface membrane ~ CO₂ from respiration diffuses out |
| how are Insects evolved for Gas Exchange | ~ Tracheae, Internal Network of Tubes ~ Spiracle, pores on surface ~ Tracheae support by Chitin (Strengthened Rings) -> prevent Collapse ~ Tracheoles, tracheae divides into small deadend tubes -> extend throughout all body tissue |
| Structure inside Insect | |
| how are these Structures helpful for gas exchange in Insects | ~ Atmospheric air, with O₂ -> bought directly to Respiring tissue -> due to Short diffusion Pathway from tracheoles to any body cell |
| Respiratory gases move in and put of Tracheal system in 3 ways | 1. Along a Diffusion Gradient 2. Mass Transport 3. Ends of the Tracheoles filled with Water |
| 1. How does O₂ enter the cell | ~ O₂ concentration decreases inside end of Tracheoles -> cuz, O₂ used up during Respiration ~ this creates Diffusion Gradient causing Gaseous O₂ to enter cells -> from atmospheric air -> through Tracheae & Tracheoles |
| 1. how does CO₂ leave the cell | ~ CO₂ concentration increases inside end of Tracheoles -> cuz CO₂ produced during Respration ~ this created conc. gradient in the other way causing Gaseous CO₂ to leave cells -> from Tracheoles to atmospheric air |
| 2. what is Mass Transport | ~ Contraction of muscles in insects can squeeze the Trachea -> enabling mass movement of air in and out ~ this further speeds up the exchange of respiratory gases |
| what happens when the Muscle cells around the Tracheoles respire Anaerobically? How does H₂O enter cells? | ~ produce Lactate, during major Activity ~ Lactate is soluble -> Lowers the water potential of muscle cells ~ H₂O moves Into cell from Tracheoles by Osmosis |
| how does Air move into the Tracheoles? | ~ H₂O in ends of Tracheoles decreases in volume ~ so Air is drawn into the Tracheoles |
| what is the Final diffusion pathway? downside? | ~ in a Gas rather than Liquid phase -> increases the rate of air flow into Tracheoles ~ but also Greater Water Evaporation |
| what are Spiracles? | ~ Gases enter and leave through tiny pores ~ on Body surface ~Opened and Closed by Valves |
| why don't Insects keep Spiracles open all the time? When do they open? | ~ Water vapor can evaporate from spiracle ~ > closed to Prevent water Loss ~ periodically open to allow Gas exchange |
| Limitations of the Tracheal system | 1. relies Mostly on Diffusion to exchange between environment and cells -> for effectiveness -> diffusion pathway must be short 2. Limits size of Insects -> due to length of pathway |
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