First

• ### James Craver

Now I see how peptide bonds can form. Excellent!

• ### William Smith

Why is this video uploaded twice?

• ### Renny Hoang

Under 301 club

• ### Mouad Alami

I thhink that the carbone 4 in the fructose molecule is missing a hudrogen

Thanks Sal.

• ### AVO

@Khan Academy In a division problem or any kind of problem can I for instance directly  dived 50.50cm^3 by 15.0cm^2 or would i have to convert one in order to do this problem

• ### David Lloyd-Jones

Alejandro,

In the example you give you have a two scalars, the numbers 50.5 and 15, and two sets of units, the cm^3 and the cm^2.

In this case you've got no big problems, because numbers divide into numbers and c^3/cm^2 is simply cm (or cm^1 if you like).  So you've divided a volumve, 50.5 cm^3 by an area, the 15 cm^2, and naturally you ge a distance,  3.36666… cm.

If you think of this in physical terms, a volume divided by an area might be a question about "how high is a tower of something if you know the area of the base?"

Best,

-dlj.

• ### Patrick Garcia

These videos are incredibly informative for me. For whatever reason the textbook would never be enough. Props to Khan Academy

• ### Correctrix

"Carboneeel"? :p

• ### Arpita Saxena

how can both of them be carboxyl group

• ### Prabhanshu Katiyar

u said amino 'acid' and then u said that its a base???

• ### Tanisha Goel

Thank you ^_^

usefullllll

• ### tracy scanlon

Too much on the board to follow, sorry

• ### Ruby Hagrid

I've been looking everywhere for visual explanation of the functional groups, and no one does it better than you Sal! Thank you so much!

voice??

• ### belal kamel

So bad, what a anarchist explanation !!

• ### Cristina Lingvay

Mr Khan literally teaching the world

• ### Zachary

Helped me out a lot!!

• ### Cataleya Sazo

life saver. got a bio midterm tomorrow

thanks

• ### Prajwall Narayana

Anyone from CBSE class 10

Outstanding

• ### Kristin Ford

You are amazing. I always find myself fascinated by your educating ways.

• ### DKiNG LJ

You forgot to mention the sub groups in carbonyl (aldehyde and ketone)

• ### yahvonne

you pronounced carbonyl wrong