Exchange between organisms and their environment

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  • Created by: LucySPG
  • Created on: 27-05-13 12:46
What is the name of the exchange of gases between an organism and its environment?
Diffusion
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What is the part of the organism across which the exchange of gases takes place?
The gas exchange surface
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Name two things that will affect the amount of each material that needs to be exchanged
Size and metabolic rate of an organism
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What does size and metabolic rate influence?
The type of exchange surface and transport system that has evolved to meet the requirements of each organism
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Name four things that need to be interchanged between an organism and its environment
Respiratory gases, nutrients, excretory products and heat
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What are the two ways exchange can take place?
Passively - by diffusion and osmosis where no energy is required. Actively - by active transport where energy is required
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Where does exchange take place?
At the surface of an organism
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What must an organism have for exchange to be effective?
A large surface area to volume ratio
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What happens as organisms become larger?
Their volume increases at a faster rate than their surface area
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How have large organisms overcome this problem?
A flattened shape so that no cell is ever far from the surface and specialised exchange surfaces with large areas to increase the surface area to volume ratio
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How are exchange surfaces adapted for gas exchange?
Large areas that are thin as possible to allow rapid diffusion of gases
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What else do organisms have to take gases to and from the exchange surface?
Transport system
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How does the transport system ensure efficient gas exchange?
Ensures gases are moved rapidly between the body cells and the gas exchange surface but also maintains a concentration gradient for the gases across the exchange surface
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What happens if the concentration gradient is greater?
Diffusion occurs more rapidly
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What are the five features of specialised gas exchange surfaces?
Large surface area to volume ratio, thin, partially permeable, movement of environmental and internal medium
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How does the movement of the environmental and internal medium allow effective transfer of materials?
Maintain a diffusion gradient
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Diffusion is proportional to.....
surface area x difference in concentration / length of diffusion path
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Why are exchange surfaces often located inside the body?
Because they are thin and easily damaged
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Why can single-celled organisms exchange gases quickly?
They are small and have a large surface area to volume ratio
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Other cards in this set

Card 2

Front

What is the part of the organism across which the exchange of gases takes place?

Back

The gas exchange surface

Card 3

Front

Name two things that will affect the amount of each material that needs to be exchanged

Back

Preview of the front of card 3

Card 4

Front

What does size and metabolic rate influence?

Back

Preview of the front of card 4

Card 5

Front

Name four things that need to be interchanged between an organism and its environment

Back

Preview of the front of card 5
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