Evaluate - why is it important that cells are able to use both active and passive tra

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Courtneyks
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Hello, I have to evaluate the above statement in Biology, but I am not sure and the resources I have don't go into detail. Can anybody help? I have around 125 characters to answer this as-well.

Thank you
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macpatgh-Sheldon
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Hi are you sure you mean "125 characters"? Is it a one mark Q cos 20 odd words is cashewnuts!
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Courtneyks
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Ah my bad I meant 125 words lol!

(Original post by macpatgh-Sheldon)
Hi are you sure you mean "125 characters"? Is it a one mark Q cos 20 odd words is cashewnuts!
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macpatgh-Sheldon
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Passive transport is by diffusion or osmosis where the concentration gradient permits efficient movement of solutes or water, respectively. This can be useful when no great supply of ATP is forthcoming.
However, when a cell needs to transport s-t against a concentration gradient or in another situation where passive methods are insufficient or completely absent, then active movement aided by energy-using mechanisms become crucial. Such a situation could arise due to e.g. a molecule being charged so that it is not lipophilic enough to cross the phospholipid cell membrane OR it could be because the molecule is too polar i.e. hydrophilic.

Then you should give examples: e.g. diffusion of oxygen across the alveolar wall + capillary endothelium intro the blood in the lungs (passive);
Absorption of amino acids in the ileum [small intestine] - (active using specific carriers);
Reabsorption of glucose in the proximal tubule of the kidney (active using GLUT), etc.
Active transport of Na+ against conc gradient to maintain resting potential in the neurone (using Na+, K+ - ATPase [sodium-potassium pump];
Etc
Etc

Oc write in your own words after you read and understand the above - look up more detail online or in books e.g. facilitated diffusion - if you need help with this, pls feel free to PM me - I shall point you in the right direction.

Best wishes & be safe!
M.
Last edited by macpatgh-Sheldon; 7 months ago
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Courtneyks
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(Original post by macpatgh-Sheldon)
Passive transport is by diffusion or osmosis where the concentration gradient permits efficient movement of solutes or water, respectively. This can be useful when no great supply of ATP is forthcoming.
However, when a cell needs to transport s-t against a concentration gradient or in another situation where passive methods are insufficient or completely absent, then active movement aided by energy-using mechanisms become crucial. Such a situation could arise due to e.g. a molecule being charged so that it is not lipophilic enough to cross the phospholipid cell membrane OR it could be because the molecule is too polar i.e. hydrophilic.

Then you should give examples: e.g. diffusion of oxygen across the alveolar wall + capillary endothelium intro the blood in the lungs (passive);
Absorption of amino acids in the ileum [small intestine] - (active using specific carriers);
Reabsorption of glucose in the proximal tubule of the kidney (active using GLUT), etc.
Active transport of Na+ against conc gradient to maintain resting potential in the neurone (using Na+, K+ - ATPase [sodium-potassium pump];
Etc
Etc

Oc write in your own words after you read and understand the above - look up more detail online or in books e.g. facilitated diffusion - if you need help with this, pls feel free to PM me - I shall point you in the right direction.

Best wishes & be safe!
M.
Thank you for your help! this was really informative and well put!
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macpatgh-Sheldon
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No hassle and thanks so much for the rep! It makes the one-finger typing worthwhile!
Have a great day!

M.
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