Suppose that certain root cells have an overall charge that is more negative than normal. What impact would this likely have on the uptake of anions such as NO3−? a., Anions would be less likely to enter roots. b. Anions would be more likely to enter roots. c. This would have no impact on the ability of anions to enter roots. d. This would make anions and cations equally likely to enter roots.

Video transcript

Welcome back. Let's look at our next question. It says, how are an ions like N. 03 minus able to enter root hairs despite their electrochemical gradient so that despite clues us in that we're talking about the transport of ions across a cell membrane against an electrochemical gradient. So transporting these ions from a region of lower concentration to higher concentration inside the root. So let's take a look at our answer choices for the way they're able to do that choice A. Says through ion channels. Well this is not our answer, even though ion channels are membrane proteins that can transport ions but in their case they transport ions down the gradient so into regions of lower concentration. So that's not sufficient for this case. What we're talking about going against the electrochemical radiant choice B says through co transporters and this is correct. Co transporters we can recall from our content video are membrane proteins that couple the favorable movement of one molecule with the unfavorable movement of another molecule. So in this case the co transporters, couple pumping protons or not pumping, pumping, pumping implies active couple transporting protons down there electrochemical gradient with the transport of an ions that's kinda see her against their gradient and that worked successfully because the transport of protons in a favorable direction generates so much energy that it easily makes up for the energy needed to transport the alliance against the gradient. So co transporters harness those two things together, couple them together, allowing the aliens to enter the root hairs. Um Well, just look at our last two answers to be thorough Choice C says. Through pores. Um pores are not sufficient to allow ions to go through between cells. That's only for water, en choice D says, through a simple diffusion. Well, that's not our answer. Either, ions cannot diffuse through a membrane. The charged ion will not diffuse through the non polar cell membrane. So again, how are anons like nitrate able to enter root hairs despite their electrochemical gradient choice? Be through co transporters. See you in the next video.