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GCSE Biology cell biology question help

I have a question in a practice paper idk about, any help im very grateful ty
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(there is a diagram showing two guard cells surrounding a closed stomata and two guard cells surrounding an open stomata
)
when light intensity is high potassium ions are moved into the guard cells

describe how the movement of potassium ions into the guard cells causes the stomata to open?
Original post by temanbaik
I have a question in a practice paper idk about, any help im very grateful ty
-----------------------------------------------------------
(there is a diagram showing two guard cells surrounding a closed stomata and two guard cells surrounding an open stomata
)
when light intensity is high potassium ions are moved into the guard cells

describe how the movement of potassium ions into the guard cells causes the stomata to open?

How would the ion concentration change in the guard cells? What would happen to the water potential? So what would happen in terms of osmosis?
Reply 2
Original post by booklover1313
How would the ion concentration change in the guard cells? What would happen to the water potential? So what would happen in terms of osmosis?

hmmmmmmm ic ic thank you i see where this is going a bit!!
Original post by temanbaik
hmmmmmmm ic ic thank you i see where this is going a bit!!

Great! What do you think the full answer is?
Reply 4
Original post by booklover1313
Great! What do you think the full answer is?

as the potassium ions move into the stomata by diffusion, the water potential inside the stomata decreases and so the stomata open in order to allow water to move into the stomata by osmosis. Nvm, my answer is bad and definitely not worth 4 marks. This topic is really hard :frown: how do you revise?
Original post by temanbaik
as the potassium ions move into the stomata by diffusion, the water potential inside the stomata decreases and so the stomata open in order to allow water to move into the stomata by osmosis. Nvm, my answer is bad and definitely not worth 4 marks. This topic is really hard :frown: how do you revise?

You are really close!
What happens is that
The potassium ions are moved into the guard cells. This increases the concentration of ions in the cells, and so the water potential in the guard cells decreases. Therefore, water moves by osmosis from the surrounding cells into the guard cells, because water moves from an area of high water potential to an area of low water potential. The increased volume of water in the guard cells causes them to swell, and their change in shape causes the stomata to open.

Does that make sense?
(edited 1 year ago)
Also, just to check, the stomata open for air to flow in - so water would enter in the form of water vapour, not in liquid form. They are like holes. They themselves don't have water potentials, but the surrounding guard cells do.
Reply 7
Original post by booklover1313
You are really close!
What happens is that
The potassium ions are moved into the guard cells. This increases the concentration of ions in the cells, and so the water potential in the guard cells decreases. Therefore, water moves by osmosis from the surrounding cells into the guard cells, because water moves from an area of high water potential to an area of low water potential. The increased volume of water in the guard cells causes them to swell, and their change in shape causes the stomata to open.

Does that make sense?

yes it does THANK YOU!!! do you do a level biology? or are you gcse too?? you seem RLLY GOOD TY IM V GRATEFUL
Reply 8
Original post by booklover1313
Also, just to check, the stomata open for air to flow in - so water would enter in the form of water vapour, not in liquid form. They are like holes. They themselves don't have water potentials, but the surrounding guard cells do.



AHHHH ic ty for clarification
Original post by temanbaik
yes it does THANK YOU!!! do you do a level biology? or are you gcse too?? you seem RLLY GOOD TY IM V GRATEFUL

You're welcome!! Yeah I did Biology HL in the IB (basically equivalent to A level) :smile:
BBC bitesize has some good info, and a good diagram @temanbaik
https://www.bbc.co.uk/bitesize/guides/z28g7p3/revision/4
Original post by booklover1313
BBC bitesize has some good info, and a good diagram @temanbaik
https://www.bbc.co.uk/bitesize/guides/z28g7p3/revision/4

I love how you did this. Just how Study Help used to be, back in the days when it thrived :smile:
Original post by Reality Check
I love how you did this. Just how Study Help used to be, back in the days when it thrived :smile:

Haha thank you! I'm just trying to be as useful as I would have wanted someone to be for me whenever I had a question
Original post by booklover1313
BBC bitesize has some good info, and a good diagram @temanbaik
https://www.bbc.co.uk/bitesize/guides/z28g7p3/revision/4

Thank you so much, I really appreciate it!! :smile:
Original post by booklover1313
Haha thank you! I'm just trying to be as useful as I would have wanted someone to be for me whenever I had a question

It's great to see. Rather than try to be the first person to show off and give the full answer, you carefully guided the OP to the answer, encouraging and prompting as you went. Just as it should be :smile:

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