|
Title: What are three differences between ion channels and ion transporters? Post by: saranyaallu on May 9, 2019 2. Describe how vitamin A1(all-trans-retinol) is altered to produce the visual pigment used in rhodopsin to absorb visible light. Include in your description what is structurally altered in this visual pigment upon light absorption.
3. What are three differences between ion channels and ion transporters? 4. In a chloride channel, an α-helix is found to be part of the specificity filter. Which end of the helix do you expect to be interacting with the chloride anions and why? Title: Re: What are three differences between ion channels and ion transporters? Post by: bio_man on May 9, 2019 2. Describe how vitamin A1(all-trans-retinol) is altered to produce the visual pigment used in rhodopsin to absorb visible light. Include in your description what is structurally altered in this visual pigment upon light absorption. You may want to read the uploaded document or using the link here (https://biology-forums.com/index.php?action=downloads;sa=view;down=12813) The document is called: The Synthesis of Rhodopsin from Vitamin A1 Title: Re: What are three differences between ion channels and ion transporters? Post by: bio_man on May 9, 2019 3. What are three differences between ion channels and ion transporters? Ion channels don't usually require ATP hydrolysis, ion transporters do (active transport). Ion transporters are designed to push molecules against their concentration gradient, ion channels allow molecules to flow along their concentration gradient (passive). Can't think of the last one :( Title: Re: What are three differences between ion channels and ion transporters? Post by: bio_man on May 9, 2019 4. In a chloride channel, an α-helix is found to be part of the specificity filter. Which end of the helix do you expect to be interacting with the chloride anions and why? Not sure, though this may help: https://proteopedia.org/wiki/index.php/Chloride_Ion_Channel According to the source: "The 5 positively and 5 negatively charged amino acids on each end of the alpha helices could be part of the ion selectivity of this channel." Maybe you can make sense of that... Let us know what you find Title: Re: What are three differences between ion channels and ion transporters? Post by: rosieliu on May 30, 2019 3. What are three differences between ion channels and ion transporters?
Ion channels (https://www.cusabio.com/Ion-channels.html) are pores of a class of intrinsic proteins in the cell membrane. The ion channel does not bind to the molecules being transported during transport, does not move, and the ions are transported from high to low concentrations, so they do not consume energy when transported. The ion channel is a passive transport. Ions through the passage is controlled by a door, and the opening and closing of the door is modulated by an appropriate signal. The direction of the ions depends on their charge sign, the magnitude and direction of the transmembrane concentration gradient, and the magnitude and sign of the transmembrane potential difference. The ion channel has a very high transport rate. Ion transporters are involved in active transport, which bind to the corresponding molecules during transport, and move. It moves from a low concentration to a high concentration during active transport and consumes metabolic energy. The gates of the transporter are alternately opened and closed and do not open and close at the same time. Ion transporter has a low transport rate compared to ion channel. To learn more about the differences between ion channels and ion transporters, read the article below. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2742554/ |