Aquaporins are proteins embedded in the cell membrane that regulate the flow of water - you don't really need to know this for AS, as it is on the spec in F214 when you learn about osmoregulation (I'm an A2 student)
A spirometer consist of a chamber filled with oxygen that floats on a tank of water. A person breaths from a disposable mouthpeice attached to a tube connected to the chamber of oxygen (medically graded). Breathing in takes oxygen away from the tank causing the lid of the tank to move down. Breathing out forces air into the tank causing it to move up.
The movements are recorded on a data logger so a trace can be made
This is like the procedure of how a Spirometer works, sorry if it still seems like jargon
Thank you this made more sense than my text book. I just hope they don't ask us to calculate the tidal volume or anything like that.
I think that would get one mark. Water is never part of active transport to my understanding.
The mark would be 1. through channel proteins and 2. water can simply move across the membrane by osmosis as it is permeable to water.
Actually, the phospholipid bilayer is impermeable to water (due to the hydrophobic lipid tails), it's only permeable to small, non-polar molecules such as carbon dioxide and oxygen. So really there's only one route through the cell surface membrane and that's through channel proteins
Aquaporins are proteins embedded in the cell membrane that regulate the flow of water - you don't really need to know this for AS, as it is on the spec in F214 when you learn about osmoregulation (I'm an A2 student)
Yep was just going to write that. Are you resitting f211 aswell. It was more than a year since we covered the syllabus in class
Actually, the phospholipid bilayer is impermeable to water (due to the hydrophobic lipid tails), it's only permeable to small, non-polar molecules such as carbon dioxide and oxygen. So really there's only one route through the cell surface membrane and that's through channel proteins
Some water molecules can pass through even though water is polar.
1. State 3 roles of membranes inside cells - 3 marks
2. Outline how vesicles are moved from one organelle to another - 2 marks
3. Why is it important that products of photosynthesis can be moved in both directions through sieve tubes? 1 mark
1. forms seperate organelles. controls what substances enters and exits organelles - 2. the cytoskeleton is made out of micrrotubule which provides a track for vesicle. it uses ATP to allow movement
3. so that sucrose can reach all parts of the plant and can be stored so that it can be used for respiration (?)
Actually, the phospholipid bilayer is impermeable to water (due to the hydrophobic lipid tails), it's only permeable to small, non-polar molecules such as carbon dioxide and oxygen. So really there's only one route through the cell surface membrane and that's through channel proteins
No it is partially permeable. Water molecules can pass through the phospholipd bilayer regardless that it's hydrophobic and what not. So even though water molecules are polar, they are still able to pass through the bilayer.
Yep was just going to write that. Are you resitting f211 aswell. It was more than a year since we covered the syllabus in class
I'm doing it for a third time! (don't laugh ) - I'm aiming to get full marks so I don't have to do as well on F215. At the moment I need 124/150 for an A, but I could get it down to 101/150.
How about you?
P.S. That is what happened to me in Jan (my UMS only went up by 4!), as the F211 material wasn't very prominent in my mind and I thought I could manage it without doing much revision... I was wrong lol
No it is partially permeable. Water molecules can pass through the phospholipd bilayer regardless that it's hydrophobic and what not. So even though water molecules are polar, they are still able to pass through the bilayer.
I hate to say that you are wrong...
polar / ionic ; cannot pass through , phospholipid layer / hydrophobic regions ; use , protein channels / protein carriers / transport proteins ; (protein channels with) hydrophilic , lining / channel / core ; (3 max) DO NOT CREDIT water-soluble (in Q) CREDIT impermeable to vitamin B1 / water CREDIT transmembrane / intrinsic protein DO NOT CREDIT aquaporin
3. Why is it important that products of photosynthesis can be moved in both directions through sieve tubes?
Roots cannot obtain sugars from the soil so rely on the phloem to transport it to them from the leaves, other cells use it for metabolic activites as well as storage by converting it into starch,
Actually, the phospholipid bilayer is impermeable to water (due to the hydrophobic lipid tails), it's only permeable to small, non-polar molecules such as carbon dioxide and oxygen. So really there's only one route through the cell surface membrane and that's through channel proteins
See above - just reinforced your point about water not being able to pass through the membrane due to it's polar nature.
polar / ionic ; cannot pass through , phospholipid layer / hydrophobic regions ; use , protein channels / protein carriers / transport proteins ; (protein channels with) hydrophilic , lining / channel / core ; (3 max) DO NOT CREDIT water-soluble (in Q) CREDIT impermeable to vitamin B1 / water CREDIT transmembrane / intrinsic protein DO NOT CREDIT aquaporin