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22 Cards in this Set
- Front
- Back
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State 6 reasons as to why substances organisms need special exchange surfaces (no elaboration needed) |
Oxygen Glucose Proteins Fats Water Minerals |
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Why is oxygen useful for keeping the cell alive? |
Aerobic respiration |
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Why is glucose useful for keeping the cell alive? |
A source of energy |
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Why is water useful for keeping the cell alive? |
To transport substances, hydration |
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Why are minerals useful for keeping the cell alive? |
Maintaining water potential and helping enzyme action |
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Why are fats useful for keeping the cell alive? |
For making membranes and a source of energy (storage) |
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Why are proteins useful for keeping the cell alive? |
For growth and repair of cells |
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How may a cell obtain substances to keep alive? |
Absorbed from the surrounding environment, made in the cytoplasm as part of cell metabolism |
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True/False? Carbon dioxide is a waste product in all species Oxygen is a waste product in some species Urea, ammonia are not waste products |
True - in animals, microorganisms, and also from plant cells that are not actively carrying out photosynthesis True - not animals, in some plants (due to photosynthesis) and some protoctists False - they contain excess nitrogen |
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Define large surface area to volume ratio |
a large amount of area per unit of volume of an object/collection of objects |
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True/False: Once a multicellular organism becomes larger, its surface area:volume ratio decreases and its cells need more suppies |
true |
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True/False: A large multicellular organism's outer surface is not large enough to enable gases and nutrients to enter its body fast enough to keep all the cells alive by exchanging gas across their outer surfaces. |
True |
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True/False: Nutrients and gases do not have to travel a greater distance from the surface to the centre of the organism |
False Nutrients and gases have to travel a greater distance from the surface to the centre of the organism |
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How do large organisms exchange more substances? |
Combining a transport system along with exchange across their outer surfaces. |
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What do good exchange surfaces have in common? |
- large surface area - thin barrier - fresh supply of molecules on one side - removal of required molecules on the other side |
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How do you maintain a steep diffusion gradient? |
- thin barrier to reduce diffusion distance - fresh supply of molecules on one side - removal of required molecules on the other side |
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Why does having a large surface area make a good exchange surface? |
more space for molecules to pass through - often achieved by folding the walls and membranes |
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Why does having a thin barrier make a good exchange surface? |
to reduce diffusion distance |
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Why does having a fresh supply of molecules on one side make a good exchange surface? Why would removal of molecules on one side make a good exchange surface? |
to maintain a high concentration on one side and a low concentration on the other side, |
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Define an exchange surface |
A specialised area that is adapted to make it easier for molecules to cross from one side of the surface to the other |
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How could an exchange surface increase exchange? |
Active transport |
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Give some examples of specialised exchange surfaces |
Small intestine- nutrients are absorbed Liver- sugar levels in the blood are adjusted Root hairs of plants- water and minerals are absorbed Hyphae of fungi- where nutrients are absorbed |
