Conceptual overview of light dependent reactions

Seeing how light energy can excite electrons which can be used to create ATP and NADPH (with oxygen as a byproduct).

[jnjnknpn]

THIS VIDEO FINALLY MADE ME UNDERSTAND THE LESSON. NEVER UNDERSTOOD IT FROM MY TEACHER

[ali]

I had a test today on this. Studying this overnight helped me out a ton. Thank you.

[anhhuynh]

this video cleared all of my 3 years confusions about photosynthesis in just a few minutes omg

[sonjalewis]

I learned photosynthesis 30 years ago in college, from a botanist who was researching photosynthesis--Stephen Herbert. His teaching diagrams and commentary were so much like this one--focusing on the dynamics of forces and gradients. Like Diana Rogava says below, the amazing action of how oxygen gets split away from the water is not really explained by most instructors. They are too focused on naming everything--and aren't seeing the big driving forces and the recovery methods. These 2-bit instructors (1 of them was head of my whole biology department) didn't comprehend how hugely, dangerously powerful the photons are, and didn't understand that the photon drives an electron into a crazed hyperactive condition, causing the electron to leave behind a huge negativity when it exits. This enables Chlorophyll 680 to do an otherwise impossible oxidation of the tightly-bound water molecule--it rips off the oxygen so it can regain an electron for the next excitation. The H+ in the meantime accumulates, providing for gradients that cause photosynthesis to continue. And there is another type of pigment that is usually present in Photosystem II, carotenes, that detoxify the photon's radiation damage to lipids in the surrounding membrane. As you can see, the antioxidants important in your diet are crucial to the plant, too.

[oskarengl]

The different complexity levels really helped me to wrap my head around the topic :)

[rockanderson]

Really excellent overview. The mechanism of making oxygen from water was well stated as were the other focus points.

[Shazimran]

Finally ...awsome xplanation..for my son to understand . Thank you.

[pooodonklooopdoop]

I could not find a video that actually explained this properly, finally stumbled upon this!

[himalaydebsourav]

thanks dude.. now i can help many other to learn photophosphorylation .

[Gianna-ffmg]

this is so clear oh my gosh thank you thank you thank youuu!!

[dianarogava]

I never understood why water was split into oxygen and hydrogen! Now I do! thank you very much

[jonahkane]

So incredible helpful! Sal you are a Saint to me! May God bless you and keep you!

[aasnathrafeeq]

this video was neat and clean than the previous light rxn video lol

[janme]

Is Hidrogen ions that pump out from ATP sintase that can form ATP is the same ion to produce NADPH in light reaction? Or it's just pump out to the stroma to balance the centration of H ions outside and inside the membrane?

[carmenbrown]

Is there a video that explains the alternative Cyclic Electron Flow if there isn't enough NADP + available?

[nishabilkhiwal]

It is so helpful👍!I am referring why was I not here earlier!😦

[evolvedone]

I never thought Biochemistry is this easy!

[veramae]

I'm struggling.
What I want is an answer to how chlorophyll converts light energy into matter.
Learned this in college 35 years ago.
Now someone in chat has told me there is no such equation, chlorophyll doesn't do that.
So i'm googling and reading ., .. to prove them wrong. [insert evil laugh]

Been thru 3 videos so far, they just vaguely talk about "light energy". Not enough.
I'm still watching yours, but struggling.

2:46 What is ATP? I know you mentioned this, but I don't understand.
Now there's an "H plus gradient" and I give up.
I think you're talking about what I want, but its not enough.

You might consider breaking each of these steps into vids you can play picture within picture for those of us who need more hand-holding. The squiggly shapes of your hand drawn features aren't reassuring.

I'll keep looking for a video that fits what I want.
Thanks for a good start on my search, however.

[LordEgra]

Ok. What will happen in winter, when there are no leaf?

[donmalik]

Why do we have two equations for photolysis?


H2O → 2H+ + 2e- + ½O2
Or
2H2O → 4H+ + 4e- + O2

How many electrons move into photosystem 1, 2 or 4?