Lec 2 | MIT 7.012 Introduction to Biology, Fall 2004

[JustOffer]

>biology

>hard science

[MrChamp51]

I wish schools would go back to chalk boards!

[giac01]

Khan Academy explains the chemistry much better for beginners.

[listminusv]

want to see the slidessssssssssss : (



[joeaz85]

wow..this is great!! I rather listen to the lecture than reading a book on this chapter..

[thyorison]

There is a transcript of lecture 3 available.



[Deathflyer]

Nice lecture, but I had to lol @ "you may never hear 'van der Waals interaction' again"

[midgetmaster234]

jesus, this guy is stumbling over his words so much, freaking annoying. still very helpful video.

[colin8696908]

wow this camera guy needs to be fired can't see anything on the screen

[battlerosesx]

No third lesson. I'm not too sure about that.

[feiyangflash]

Wonderful lectures!

[recyclingismylife]

anybody know why (in reference to 11:30 or so) the water molecules don't form hydrogen bonds or at least have a loose affiliation between the oxygen of the water and the hydrogen of the pentane?

[thuglife6209]

This occurs because the pentane is not charged therefore it cant share an electron with the H2O. However they can form Vander wall forces (at certain distances) because of (proton) nuclear and electron attractions.

[HerrrOttoFlick]

In a first approximation hydrogen bonds are not about sharing electrons but about electrostatic interactions of highly positively partially charged atoms (H attached to N, O, F) and polary bonded N, O, F (you also can distinguish between passive and active hydrogen bonds). They occur a the position of lone pairs of N, O, F because of hybridization. The partial chargesare "located" mainly in sp2 and sp3 orbitals. Thus you can explain e. g. the structure of ice and the anomaly of water.

[HerrrOttoFlick]

Another crucial factor is the geometry of the molecule. E. g. CO2 contains two very polar bonds but because it is no dipole molecule (due to its linear geometry O=C=O) it can't form any hydrogen bonds with water molecules. On the other hand Acetone (H3C)2C=O forms two passive hydrogen bonds with water molecules because of the strong polarization of its carbonyl group.

[minkeun2000]

@recyclingismylife hydrogen bonds are only formed with hydrogens that are bonded to molecules that have pretty large disparities in electronegativity, such as oxygen.. since pentance has hydrogens bonded to the carbon, an atom not much more electronegative than the hydrogen, it does not possess enough of a dipole to engage in hydrogen bonding.

[recyclingismylife]

got a nice reply via mail...thanks! turns out the polarization of the hydrocarbon bonds is too weak to maintain a bond significant enough with water to be labeled at this level of biology/biochemistry.

[stemcdonnell]

if you dont see the slides on any lecture, open wikipedia,type in the names. and keep this page on to hear his voice. so now ya can see and hear the class

[ShiroSenda]

I used to paid over $500 per course and dread it. Now I am watching lectures in my spare time. I should of went into science instead of engineering.

[girocraz]

i pity you

[DesLivresPourChanger]

It's so a pity that we can't see the slides. And the overall quality of the video is very poor. Why not provide the slides in Powerpoint or even PDF format ? It really halves the interest of this great course to not have the slides...

[droznig]

I dont mind not seeing the slides, it helps me visualise the molecules, and if there is something im not sure about, this being youtube and youtube being on the internet, its easy for me to use some imagination and google some diagrams.

[YogzDaBeatChild]

Well, it is free.

But you can get the Transcript of the lecture and Research it youself. :)

[girocraz]

yeap in MIT free courseware

[keskivirta]

Prof W. Lewin´s lessons we can see the slides. Why not here?

[polos505]

This is like AP biology.

[calvinhobbesliker2]

Why do some students have laptops?

[vnck25]

because those students have larger laps.

[droznig]

Why dos ome students not have laptops?

[xXxXxbw18xXxXx]

I actually thought this was going to be way over my head, considering I've only had one semester of biology in my entire life, but I actually understood most of this (except what I missed from the slides' glare).

[aeonmike]

good intro

[infidelguy]

For folks complaining about there not being any slides. Simply "google image" search the terms. Helps a lot.

Good lecture. Especially toward the end. People learn better when you make it relate to them.

[bogart99]

I got lost half way through and had to watch it again. It would have been usefull if we could have seen the diagrams

[peymaania]

You'd think MIT would have better technical capabilities than an overhead projector from

the 1950's...I mean WTF?

[Lima547]

Thanks for publishing a video which can elucidate peoples doubts about science! It makes Youtube worthy to use...

[mnuez]

Part one was great but it's been over a dozen years since I heard a word about chemistry so I really didn't get much out of this and quit half way through - particularly on account of the overhead projectpr not being able to aid in any illustration.

[JanusthePhoenix]

Eye opening! It's great that this kind of education is free to the public.

[mikallang]

this is indeed a very wonderful thing. i dont think anyone would have even had the notion to hope for this kind of thing 10 years ago.

[000nihao007]

long live the organic sciences!

[calvinhobbesliker2]

Well, he's not a paleontologist.

[ScientiaVeritasEtLux]

WOW, hahaha, I can't believe I've gotten 6 thumbs downs. That's crazy. I wasn't making fun of the guy. I was just pointing out that it was kind of funny that he was so off on the date. In fact he is one of my idols. As I made sure to include in my original post, "he's an incredibly brilliant biologist", and "he is....incredible". I intentionally didn't make my comment sound rude or demeaning. I was simply pointing something out. I really don't think I deserved 6 thumbs-downs. But whatever.

[colinofedinburgh]

Excellent lecture, wish I could see the slides!

[idontbelievereligion]

150 000 000 years?