LGS A-Level OCR Biology - Unit 3 - Gas exchange and Ventilation in Bony Fish and Insects
As organisms get larger, the diffusion distance increases, meaning gases must travel further to reach cells. This makes simple diffusion less efficient, so larger organisms need specialized gas exchange systems to meet their oxygen demands.
As organisms get larger, what happens to the size of the diffusion distance?
It increases
Key Terms
As organisms get larger, what happens to the size of the diffusion distance?
It increases
As organisms get larger, what happens to the size of the surface area?
It increases
As organisms get larger, what happens to the size of volume?
It increases
As organisms get larger, what happens to the size of the SA:V?
It decreases
Why do more active organisms have a greater demand for Oxygen and Glucose?
more energy is required for more movement
more ATP must be produced
more aerobic respiration must occur
What are the 4 features of efficient exchange surfaces?
increased SA
thin layers
good blood supply
ventilation to maintain diffusion gradient (for gas...
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| Term | Definition |
|---|---|
As organisms get larger, what happens to the size of the diffusion distance? | It increases |
As organisms get larger, what happens to the size of the surface area? | It increases |
As organisms get larger, what happens to the size of volume? | It increases |
As organisms get larger, what happens to the size of the SA:V? | It decreases |
Why do more active organisms have a greater demand for Oxygen and Glucose? |
|
What are the 4 features of efficient exchange surfaces? |
|
Why does an increased surface area make an exchange surface more efficient? | Provides the area needed for exchange surface to overcome the limitations of low SA:V ratio |
Why do thin layers make an exchange surface more efficient? | The distances that substances have to diffuse across are shorter making diffusion quicker |
Why does a good supply make an exchange surface more efficient? | The greater the difference in concentration the greater the rate of diffusion, a good blood supply means substances are constantly being delivered and removed, maintaining the steep concentration gradient |
Why does ventilation increase the efficiency of a gas exchange surface? | Helps to maintain a steep concentration gradient |