To help with the confusion involving the Aromatic Tyrosine and Tryptophan, as well as the Non-Aromatic Methionine; let it be considered that all three are Amphipathic amino acids. This means that they tend to have both polar and non-polar characteristics within their structures. Amphipathic amino acids are often found at the surface of proteins or lipid membranes, which is why they are sometimes classified as polar. However, even though Tyr and Trp have polar groups (-OH and the indol nitrogen), which can H-bond, these AAs are still hydrophobic due to their large hydrocarbon content. Methionine, on the other hand, tends to stay closer to the center of cells because it is mostly non-polar due to having the non-polar hydrocarbons, which is why most of the time you see that it is such. However, it is also weakly polar due to its thioether in the side chain, giving it amphipathic characteristics. *knowing the polarity properties of the groups "within" side chains will help you get a better understanding of amino acids overall characteristics.*
1:42 This is probably beyond the scope of this video, but the hydrophobic amino acids do interact with water through van der Waals forces. The hydrophobic effect is very complex and involves subtle entropic effects, for example, hydrophobic side-chains force surrounding water molecules to adopt entropically unfavorable "structured" (clathrate cage) configurations.
I thought that since it had an OH group on the arene structure, it turns the arene and the OH into a phenol group, and phenol groups are defiantly polar.
3:00 Glycine is not normally counted among the hydrophobic amino acids. The side-chain is so small (-H) that the properties of the amino and carboxylic acid groups dominate. Pure glycine is highly soluble in water.
Some of the shorthand notation for the basic amino acids is incorrect. Lysine is listed as having CH2(CH2)2-NH2 as the side chain when the correct notation would be CH2CH2CH2CH2NH2 as the side chain is just a chain of 4 saturated hydrocarbons and then an amino group. This issue is also present in the shorthand for Arginine which should be CH2CH2CH2NHC(=NH2)(NH2), not CH2(CH2)2. The parentheses indicate that there would be two CH2 groups attached to the first carbon in the chain, which is not how these amino acids look. I really hope this gets fixed or it could really confuse people about the structure of those side chains.
Very nice, but I would like to point out that tyrosine really is hydrophobic. This is because, even though it has a hydroxyl, the aromatic portion is so big and bulky that the amino acid is hydrophobic overall.
But methionine has a sulphur atom in the side chain so why is it non-polar if the neutral polar amino acids are that way because they have either an oxygen or a sulphur atom in the side chain?
But asparagine and glutamine also have nitrogens in their side chains. From how you explained remembering basic amino acids (by seeing there are nitrogens) shouldn't asparagine and glutamine also be basic ? You skipped over them in your neutral amino acid explanation saying those have oxygens or sulfur.
The have nitrogen but to a side not in the straight linear chain that's why not counted. As well as tryptophan has nitrogen but not counted because the aromatic behaviour prevent it to make amino acid basic.
Depends on the type of protein. If it is water soluble protein hydrophilic amino acids will be on the surface while hydrophobic amino acids will be in interior to maintain the protein structure. If it is membrane surface protein then hydrophobic amino acids will be on the surface and hydrophilic amino acids will be in the interior. So it depends upon the type of protein.
We learnt that there are 5 types of aminoacids Posetive Negative Polar nonPolar and Aromatic can one amino acid be in 2 groups ? because Serine according to you is Polar but it also have charge so not sure wheather i should put it as posetive\ or polar help please ?
Alkaline means basic in nature while alkyl is formed when one H is removed from an alkane, Like -CH3 is alkyl group( 1 H has been removed from methane i.e CH4) and is called methyl. And that is how you proceeed to other alkanes
Oxygen is more likely to give away protons in the form of a positively charged hydrogen making it more of an acid. Nitrogen however usually receives this proton making it basic. It is helpful to memorize that acids tend to give away protons while bases like to receive them. I hope this helped.
+jordan haynes its in reference to sterochemistry of the molecule itself. L-amino acids are the ones that we use in our body and most commonly found in nature. Someone with PKU should not have to worry about the L- prefixes.
IMHO, the way she explains the basic aa is not very accurate. Trp has N on the side chain, but it’s non polar. Gln has N on the side chain, but it makes an amide, so it’s polar neutral.
Appriciate the work, but this video has a lot of small damning mistakes which makes it counterproductive and leads to us students having to spend a lot of time looking things up.
This video has an error. The amino acids that are basic are basic because the side chain Nitrogens have a lone pair that they can DONATE. It’s not willing to accept electrons and if it were it would be acidic.
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Explained this in a much easier way than my professor. Thank you!
Who else listens to a particular video over and over and over again until you get that light bulb moment on each category discussed?
Same here man, science high five!
Your voice is articulate and easy to focus on
Alcohol groups as side chains make amino acids polar.
Yup..it forms h-bondig right with water...
To help with the confusion involving the Aromatic Tyrosine and Tryptophan, as well as the Non-Aromatic Methionine; let it be considered that all three are Amphipathic amino acids. This means that they tend to have both polar and non-polar characteristics within their structures. Amphipathic amino acids are often found at the surface of proteins or lipid membranes, which is why they are sometimes classified as polar. However, even though Tyr and Trp have polar groups (-OH and the indol nitrogen), which can H-bond, these AAs are still hydrophobic due to their large hydrocarbon content. Methionine, on the other hand, tends to stay closer to the center of cells because it is mostly non-polar due to having the non-polar hydrocarbons, which is why most of the time you see that it is such. However, it is also weakly polar due to its thioether in the side chain, giving it amphipathic characteristics. *knowing the polarity properties of the groups "within" side chains will help you get a better understanding of amino acids overall characteristics.*
This video saved me thank u so much❤❤
'The wife' told me to get ride of my " side piece."
I told her I would replace it with my own individual
"side chain "
1:42 This is probably beyond the scope of this video, but the hydrophobic amino acids do interact with water through van der Waals forces. The hydrophobic effect is very complex and involves subtle entropic effects, for example, hydrophobic side-chains force surrounding water molecules to adopt entropically unfavorable "structured" (clathrate cage) configurations.
4:36 Tyrosine is also aromatic.
Correct, but I assume she left it out of the group of aromatics due to the polarity conferred to it by its hydroxyl group.
I thought that since it had an OH group on the arene structure, it turns the arene and the OH into a phenol group, and phenol groups are defiantly polar.
powerful presentation ,you really explained it better and it's now easier for me to classify amino acids ..Thank you
Voice with synchronisation to the written manner is a great idea.....
Thank you so much, very big help for my orgo 2 final exam
I love your voice that makes me feel good.
The more I turned down my volume, the louder she got
It is the vocal fry ...makes her voice so hard on my ears.
Same😪
Are you wearing headphones?
Thank You!
Great video really helped me understand my text. NOTE: The -CH2 group is missing in the structure of Tyrosine. Thanks!
Regarding the drawing of tyrosine, the CH2 group is there para to the hydroxyl; it is represented by an angle in the structure.
Actually I love her voice
Thank you so much for these lecs!!!!!!
The God has bestowed her with that particular voice and hence cannot be criticised
Well explained 🙏🏻☺️
keep it up wonder full lecture
3:00 Glycine is not normally counted among the hydrophobic amino acids. The side-chain is so small (-H) that the properties of the amino and carboxylic acid groups dominate. Pure glycine is highly soluble in water.
You're right, at least in near neutral pH (as plasma, or any pH around 3-9) it has both groups charged, thus polar! Nice annotation.
Thank you. Very well summarized.
Some of the shorthand notation for the basic amino acids is incorrect. Lysine is listed as having CH2(CH2)2-NH2 as the side chain when the correct notation would be CH2CH2CH2CH2NH2 as the side chain is just a chain of 4 saturated hydrocarbons and then an amino group. This issue is also present in the shorthand for Arginine which should be CH2CH2CH2NHC(=NH2)(NH2), not CH2(CH2)2. The parentheses indicate that there would be two CH2 groups attached to the first carbon in the chain, which is not how these amino acids look. I really hope this gets fixed or it could really confuse people about the structure of those side chains.
I really love her voice
quality of the video was ok
Very nice, but I would like to point out that tyrosine really is hydrophobic. This is because, even though it has a hydroxyl, the aromatic portion is so big and bulky that the amino acid is hydrophobic overall.
Isn't Tyrosine aromatic?
It is aromatic for sure, but also polar I guess?
+nathan stumpf Yes that is due to the hydroxyl group it bears.
Okwor Neechi yes Nathan is right, it has hydroxyl group making it polar
Right? It's aromatic and it's important that it's classified under aromatic because those 3 contribute to fluorescence
I never fully attend the khan academy class becz of its methode
plz you change ur methode of lecture
regards
Big thanks for you, you’ve made this aa stuffs be an easier one to acquire
Thanks alot.....
0:59 video starts
But methionine has a sulphur atom in the side chain so why is it non-polar if the neutral polar amino acids are that way because they have either an oxygen or a sulphur atom in the side chain?
Hey umm thank you so much for this!! You're voice is really cute by the way
@I'M NOT sAD I'M JUsT TIRED lmao
CAUTION: Tyrosine is NOT considered hydrophilic/polar... the AAMC considers tyrosine as a non-polar/hydrophobic aromatic amino acid
Thanks 😊 🙏
Hii there ..shouldn't proline be classified under aromatic side chain group?? please tell me..
wooooooooow! good lecture keep it high
Thanks
But asparagine and glutamine also have nitrogens in their side chains. From how you explained remembering basic amino acids (by seeing there are nitrogens) shouldn't asparagine and glutamine also be basic ? You skipped over them in your neutral amino acid explanation saying those have oxygens or sulfur.
The have nitrogen but to a side not in the straight linear chain that's why not counted. As well as tryptophan has nitrogen but not counted because the aromatic behaviour prevent it to make amino acid basic.
I love your voice.
Great video!!! helps alot
Thank youuuuu 🤪
THANK YOU!
1:05 There are 21 proteinogenic amino acids in most organisms! The 21st is selenocysteine.
I think cystine is hydrophobic?
So hydrophillic will be on the surface of a protein and hydrophobic in the interior?
Depends on the type of protein.
If it is water soluble protein hydrophilic amino acids will be on the surface while hydrophobic amino acids will be in interior to maintain the protein structure. If it is membrane surface protein then hydrophobic amino acids will be on the surface and hydrophilic amino acids will be in the interior. So it depends upon the type of protein.
Your sound is aromatic
We learnt that there are 5 types of aminoacids
Posetive Negative Polar nonPolar and Aromatic
can one amino acid be in 2 groups ? because Serine according to you is Polar but it also have charge so not sure wheather i should put it as posetive\ or polar help please ?
Nice
thankyouuuuu
What about glycine?
my textbook teaches tyrosine as nonpolar aromatic
What is alkyl? Does it mean alkaline?
Alkaline means basic in nature while alkyl is formed when one H is removed from an alkane, Like -CH3 is alkyl group( 1 H has been removed from methane i.e CH4) and is called methyl. And that is how you proceeed to other alkanes
Why is it that in some places Cysteine is Nonpolar and in other places they say it's Polar? ughh which is it
People are talking so much trash in the comments, it's ridiculous. With this attitude, I really have no idea why you're watching MCAT prep courses.
Methionine has sulfur in its side chain. Shouldn't it be polar? Pls clarify
+GodlovesAmerica07 I simplify the real fact, but consider the S is central in methionine' side chain and does not move the electric barycentre.
The sulfur in methionine has methyl's on each side, so the dipoles cancel out. In Cysteine the sulfur only has one methyl and has a net dipole
Nice video......Good explanation :-) :-)........And guys, her voice is perfectly normal
I dont get how aminoacids with oxygen are acidic whereas those with nitrogen are basic, since both elements are electronegative.
Oxygen is more likely to give away protons in the form of a positively charged hydrogen making it more of an acid. Nitrogen however usually receives this proton making it basic. It is helpful to memorize that acids tend to give away protons while bases like to receive them. I hope this helped.
so I have to Drink a protein sub because I have pku but in the ingredients it says like L-this and L-that any ideas what those are
+jordan haynes its in reference to sterochemistry of the molecule itself. L-amino acids are the ones that we use in our body and most commonly found in nature. Someone with PKU should not have to worry about the L- prefixes.
isn't histidine aromatic?
I don't understand this lol I'm gonna fail :(
Ashley. Feel you got an exam the day after tomorrow :'(
Did you?
John Wayne I passed actually lol this was so long ago wow
IMHO, the way she explains the basic aa is not very accurate. Trp has N on the side chain, but it’s non polar. Gln has N on the side chain, but it makes an amide, so it’s polar neutral.
Good video, but the explanations and groupings aren't entirely correct.
I think she's got a pretty voice.👌🏼
i really like the handwriting
Appriciate the work, but this video has a lot of small damning mistakes which makes it counterproductive and leads to us students having to spend a lot of time looking things up.
This is how to classify amino acids. Lol I can't memorize the actual 20 Amino acids
cysteine and tyrone are hydrophobic
Lehninger refers to cysteine as polar, thus hydrophilic. But yes, tyrosine is actually nonpolar as far as I know.
Isn't Glycine hydrophilic and cysteine hydrophobic
+j edbom looked it up and no glycine is non polar and hydrophobic cysteine is neutral and hydrophilic
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I was expecting to hear Sal :[
Haterz 😂
i nutted amino acids
👍
This video has an error. The amino acids that are basic are basic because the side chain Nitrogens have a lone pair that they can DONATE. It’s not willing to accept electrons and if it were it would be acidic.
She just didnt explain it right
she sound cute af
I love your voice but you say "and" wayyyyy toooooo muchhhh
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Why does everyone teaching sound depressing af
Erotic voice, damn I ain't gonna listen to this in the library
ur voice is bothering , I couldn't complete the video please try to change its tone
+danya aziz You cant change a teachers voice...
she should try ,
hate her voice
I think you should be thankful for the free education and shut the fuck up you ungrateful fucks.
love the response ha
Very fast and poor teaching
thank you very much
Thank you