Biology A-Level Quick Questions

3. Do all channel proteins only open when there is ATP for energy available or can some channel proteins just be open permanently anyway?

I think some are open anyway. In general passive transport (which can be diffusion through protein channels) does not require ATP

4. Reabsorption of substances into the blood occurs in the proximal convuluted tubule P.C.T. (of the kidney). Sodium ions are initially actively pumped into the blood from the PCT cell wall cells. Sodium from the filtrate (in the lumen of the PCT) is then allowed to move into the cells of the PCT cell wall, and cotransport glucose and amino acids. How do sodium ions from the filtrate pass through? What do glucose and amino acids pass through to be "co-transported" into these cells? I think the answer to this is protein channels, but if so, do they pass through THE SAME PROTEIN CHANNEL AT THE SAME TIME?

All these questions are seemingly are un-answered by my textbooks, so I hope ppl on this forum can help Thanks

Ok, I just want to confirm a few things that im not too sure about in Biology.

1. In Photosynthesis you have photosystem I P700nm and photosystem II P680nm. Are the "primary pigment" that exist in these two photosystems classified as Chlorophyll a each absorbing a different wavelength of light?

2. Ok we produce reduced NADP at the end of light dependent stages. Is the equation:
NADP+ + 2H+ + 2e- = reduced NADP

OR

NADP+ + H+ + 2e- = reduced NADP

?

3. Do all channel proteins only open when there is ATP for energy available or can some channel proteins just be open permanently anyway?

4. Reabsorption of substances into the blood occurs in the proximal convuluted tubule P.C.T. (of the kidney). Sodium ions are initially actively pumped into the blood from the PCT cell wall cells. Sodium from the filtrate (in the lumen of the PCT) is then allowed to move into the cells of the PCT cell wall, and cotransport glucose and amino acids. How do sodium ions from the filtrate pass through? What do glucose and amino acids pass through to be "co-transported" into these cells? I think the answer to this is protein channels, but if so, do they pass through THE SAME PROTEIN CHANNEL AT THE SAME TIME?

All these questions are seemingly are un-answered by my textbooks, so I hope ppl on this forum can help Thanks

Ok, I just want to confirm a few things that im not too sure about in Biology.

1. In Photosynthesis you have photosystem I P700nm and photosystem II P680nm. Are the "primary pigment" that exist in these two photosystems classified as Chlorophyll a each absorbing a different wavelength of light?

4. Reabsorption of substances into the blood occurs in the proximal convuluted tubule P.C.T. (of the kidney). Sodium ions are initially actively pumped into the blood from the PCT cell wall cells. Sodium from the filtrate (in the lumen of the PCT) is then allowed to move into the cells of the PCT cell wall, and cotransport glucose and amino acids. How do sodium ions from the filtrate pass through? What do glucose and amino acids pass through to be "co-transported" into these cells? I think the answer to this is protein channels, but if so, do they pass through THE SAME PROTEIN CHANNEL AT THE SAME TIME?