I'm still holding out that you will eventually post those game walkthroughs promised on your channel description... Cheers for the biochemistry help, lad. xD
thank you for this, my professor gave us a question with "titrated with .5 M NAOH". How do i solve it when im givine M and ml of the amino acid and M of the base or acid.
Hi Leanne, absolutely! That is based on the structure of your amino acid and whether things are protonated or deprotonated. You are essentially adding up the charges on each of the side chains. If you watch the section on Alanine, at a very low pH there are a lot of H+ floating around so every part of Alanine that can be protonated is protonated (NH3+, COOH and CH3 so you have a net of +1 here because NH3+ is +1, COOH is 0 and CH3 is 0). At a pH of 6 you have (NH3+, COO-, and CH3 so you have a Net of 0 because NH3+ is +1, COO- is -1 and CH3 is 0) - this is because the pH is greater than the pka of your carboxy chain and less than the pka of your amino chain.. At high pH you have a lot of OH- floating around so this will deprotonate or pull Hydrogens off of the molecule (NH2, COO-, and CH3 so you have a Net of -1 because NH2 is 0, COO - is -1 and CH3 is 0). The net charges are directly dependent on your side chains that you have and their associated pka values because if you put the amino acid in a pH greater than the pka of one of the chains it will pull a hydrogen off because the high pH has a lot of OH- floating around. If you put the amino acid in a pH less than the pka of one of the chains it will put a Hydrogen on that chain because the low pH has a lot of H+ floating around. You want to memorize the pka's of each of the side chains as well as the amino and carboxy ends in order to make this easier on you. If you start the video around 0:50 and watch the intro this should make more sense! I hope this helps if not please let me know!
Hi Med Student. Yes, I agree this can be much more complicated than described. Essentially very amino acid will have a different alpha carboxy and alpha amino pka value depending on which reference you are using. However, the purpose of this video is to show students how to create a titration curve and find the PI value. The numbers may not be perfect but the concept will still apply even when pka values change. Good luck with your studies! Take care.
hello the thing I dont understand no matter how hard I try is that my we are dividing the summe of pks. ph scale is logarithmic. So thats why I think we shouldn't divide by 2. it must be close to coohs pk value.
Hey Pin, Yes, I understand what you mean and why that is confusing. For our purposes here everything is simplified so we can avoid using higher level mathematics. We are trying to find the Isoelectric Point which is the pka level where our amino acid has a neutral charge so we take the pka values above and below where we find our neutral amino acid, add them together and divide them by two just to find the mean value between the two. You can ignore the logarithmic scale for the purpose of this calculation mainly because we are "assuming" pH is equal to pka and to make our lives easier when doing these calculations. Hope that helps! Good luck with your studies!
@@newf5700 hey thank you for your answer. Do you know how can i find more about this calculation? I have harper biochemistry even its not explaining anything.
@@pinboard4582 There are a few youtube videos on dividing logarithms that you could use. It's a complicated process and something you probably won't be able to find in a chemistry book. Have you checked out @khanacademy? They may have something along those lines but I am not sure. I'm sorry I can't be of more help. Best of luck!
Omg thank you soo much ... I watched about 20 videos and I still didn’t understand how to do this . You are truly amazing
Lily4Real So glad I could help!
Geez! What a great video, incredibly helpful!!I was dying trying to understand this.
Thank you for your comment! It's a hard topic so well done to you!
U r the best , I can finally feel like I understand biochemistry. Plsss do make more videos
I'm still holding out that you will eventually post those game walkthroughs promised on your channel description...
Cheers for the biochemistry help, lad. xD
thank you for this, my professor gave us a question with "titrated with .5 M NAOH". How do i solve it when im givine M and ml of the amino acid and M of the base or acid.
Hi Natzoo, you’re welcome! I think you can use the Ma x Va = Mb x Vb equation to get the answer you need here.
please could you do more on biochem? I swear ill support. thank you!!!!!
Hi akemini! Which specific topics would you like videos on? I will do my best to make some more videos!
@@newf5700 membrane protein structure or carbohydrate metabolism. This one is quite detailed and I just can’t get it all
There’s no way I’ve struggled with this and failed only for you to make me understand it to the T.🥺😭😭😭😭 Why didn’t this video ranked top????😢
Thank you for your comment! It's all you, well done!
could you explain how you got the net charges (+1, 2 etc) im lost on that
Hi Leanne, absolutely! That is based on the structure of your amino acid and whether things are protonated or deprotonated. You are essentially adding up the charges on each of the side chains.
If you watch the section on Alanine, at a very low pH there are a lot of H+ floating around so every part of Alanine that can be protonated is protonated (NH3+, COOH and CH3 so you have a net of +1 here because NH3+ is +1, COOH is 0 and CH3 is 0).
At a pH of 6 you have (NH3+, COO-, and CH3 so you have a Net of 0 because NH3+ is +1, COO- is -1 and CH3 is 0) - this is because the pH is greater than the pka of your carboxy chain and less than the pka of your amino chain..
At high pH you have a lot of OH- floating around so this will deprotonate or pull Hydrogens off of the molecule (NH2, COO-, and CH3 so you have a Net of -1 because NH2 is 0, COO - is -1 and CH3 is 0).
The net charges are directly dependent on your side chains that you have and their associated pka values because if you put the amino acid in a pH greater than the pka of one of the chains it will pull a hydrogen off because the high pH has a lot of OH- floating around. If you put the amino acid in a pH less than the pka of one of the chains it will put a Hydrogen on that chain because the low pH has a lot of H+ floating around. You want to memorize the pka's of each of the side chains as well as the amino and carboxy ends in order to make this easier on you.
If you start the video around 0:50 and watch the intro this should make more sense! I hope this helps if not please let me know!
superb!!
The pka's of the carboxy terminal end and amino end are wrong, the carboxy terminal end's pka in equal to 1.82 and for the amino end is 9.17.
Hi Med Student. Yes, I agree this can be much more complicated than described. Essentially very amino acid will have a different alpha carboxy and alpha amino pka value depending on which reference you are using. However, the purpose of this video is to show students how to create a titration curve and find the PI value. The numbers may not be perfect but the concept will still apply even when pka values change. Good luck with your studies! Take care.
@@newf5700 yeah that's right, the concept will always apply whatever the numbers are, and thank you for the nice video and explanation.
hello the thing I dont understand no matter how hard I try is that my we are dividing the summe of pks. ph scale is logarithmic. So thats why I think we shouldn't divide by 2. it must be close to coohs pk value.
Hey Pin,
Yes, I understand what you mean and why that is confusing.
For our purposes here everything is simplified so we can avoid using higher level mathematics.
We are trying to find the Isoelectric Point which is the pka level where our amino acid has a neutral charge so we take the pka values above and below where we find our neutral amino acid, add them together and divide them by two just to find the mean value between the two.
You can ignore the logarithmic scale for the purpose of this calculation mainly because we are "assuming" pH is equal to pka and to make our lives easier when doing these calculations.
Hope that helps! Good luck with your studies!
@@newf5700 hey thank you for your answer. Do you know how can i find more about this calculation? I have harper biochemistry even its not explaining anything.
@@pinboard4582 There are a few youtube videos on dividing logarithms that you could use. It's a complicated process and something you probably won't be able to find in a chemistry book. Have you checked out @khanacademy? They may have something along those lines but I am not sure.
I'm sorry I can't be of more help. Best of luck!
@@newf5700 i also watched their video but it was so superficial compared to ur video. but anyways thanks for ur effort.