Photosynthesis: Crash Course Biology #8

[@stereomaster4231]

I remembered having to learn about this when I was in high school Biology so I came back to see if it would come back to me at age 37. Nope, I ended up rocking back and forth in the corner of my office in the feeble position. Then I snapped out of it... I now embrace this truth - plants turn water, sunlight, and CO2 into food using magic

[@SenatorDishTowel]

These are the notes I took. Hopefully this can further your understanding LIGHT DEPENDENT REACTIONS (STAGE 1): -Photons strike the chlorophyll in Photosystem II (PSII) and an electron absorbs the energy and gets excited (photoexcitation) -The electron travels from PSII (first protein complex of 4) along the electron transport chain (via mobile electron carriers) to harness energy. *mobile electron carriers are proteins that carry electrons along a membrane [-The chlorophyll splits a stable molecule of H2O, stealing an electron to replace the old one. Oxygen is then released from the plant. This allows us to breathe.] -The energized electrons from PSII that were picked up by the electron carriers are transported to the next protein complex, the Cytochrome Complex. -The Cytochrome Complex serves stands between PSII and PSI (all embedded in the thylakoid membrane) and uses energy from the electrons to pump hydrogen ions into the thylakoid. -Protons accumulated from the splitting of H2O and via the Cytochrome Complex now in the thylakoid then move toward the enzyme ATP synthase, which uses the energy to pack an inorganic phosphate onto ADP to create ATP. -As electrons move along the Electron Transport Chain, they lose energy -The ‘tired’ electrons become re-energized as it reaches Photosystem I and travels on another electron carrier, where all the energy is used to make NADPH. *Products of Light Dependent reactions: chemical energy in the form of ATP and NADPH, and the by-product oxygen. LIGHT INDEPENDENT REACTIONS (STAGE 2): -First phase of the Calvin Cycle is known as Carbon Fixation -Begins in the stroma (empty space of chloroplast). Involves fixing a CO2 molecule onto Ribulose Bisphosphate (RuBP) with the help of an enzyme RuBisCo. This causes the RuBP to become unstable. -This new 6-carbon chain has to break apart, creating two molecules of 3-phosphoglycerate, which occurs to three molecules of RuBP. -Second phase of the Calvin Cycle is called Reduction. -ATP combines a phosphate group onto the 3-phosphoglycerate and NADPH packs some electrons, creating 2 molecules of Glyceraldehyde 3-Phosphate (G3P). -G3P is a high energy, 3-carbon compound that plants can convert into many carbohydrates such as glucose, cellulose, or starch. (glucose=short term energy / cellulose=structure / starch=long term energy) -The last phase of the Calvin Cycle is call Regeneration. -9 ATPs and 6 NADPHs are required to convert the 3 RuBPs we started with into 6 G3Ps. However, only one G3P can leave the cycle... the other 5 G3Ps are needed to regenerate the original RuBPs, completing one round of the cycle. Hope this helps!

[@toaruargonaut4254]

Ahhhhhh thank you so much!! I was rewinding the video every 20 sec and still didn’t get it at the end, this helps to make sooooo much sense *hug you tight*

[@moriahsun]

remember in elementary school when all you needed to know is: photosynthesis needs the sun, water and carbon dioxide to make food? Now it has come to this.

[@VioletLovesJesus724]

THANK YOU!

[@noahle7010]

pepperidge farm remembers

[@harbinger5584]

Moriah Sun xD

[@metzli_moon]

I remember "carbon dioxide" being dumbed to just being "air" even. Sun, water, and air. How things have changed lol.

[@little-furina]

Elementary: Sun light is absorbed by the plant! High School: Protons move out of the thylakoid concentration through ATP Synthase.

[@silentofthewind]

Mitochondria are the powerhouse of the cell. That's what I've learned so far.

[@madihatasnim6971]

yeh can we write that in the exam???

[@ericiuh]

@@madihatasnim6971 nope. And thats all ik

[@jacksonreventan]

Mitochondria is for aerobic respiration. And they create atp in all organisms. Photosynthesis is done in chloroplasts. Atp is not what it is for

[@multiversalman4270]

We shall watch your career with great interest.

[@AP_Monke]

@@multiversalman4270 indeed

[@AG-sj9vt]

Who else zones out during the video and then has to rewatch it again...and again...

[@chloroplast8611]

FINALLY I WATCHED IT 34 TIMES FROM THE PAST 2 WEEKS AND I UNDERSTAND EVERYTHING except the parts after the co2 molecule gets stuck to that long chain thing. I cant believe it. I dont understand myself. and btw i am NOT just a huge sac of chlorophyl. I cant believe people keep thinking my chemicals are bad. You are all lucky you even have some energy you can digest and store as fat or use the carbs that we work so hard on maintaining and building for your quick sources of energy As soon as i find a replacement for oxygen you humans will pay for this AND WOULD YOU PLEASE STOP CUTTING THE TREES DOWN!!! Why dont you humans just move to outerspace since you think your so much smarter than us. We were here first. btw and evolution is the only real creator. ~the Chloroplast

[@jibrilosman5078]

Meeeeeee

[@ravenwolf2220]

Making notes on the video is a good way to avoid that happening

[@GhostSamaritan]

@@ravenwolf2220 Or popping Adderall.

[@malihaislam3563]

Meeeee....mad annoying

[@chloeholtz9158]

I appreciate the fact that he admits this process is stupidly hard for no reason except... science😂

[@pattyfarinas803]

Finally someone who just admits that this whole process is overly complicated for no reason at all

[@blockydogy1188]

lol what

[@blockydogy1188]

it’s complicated but so is everything? nobody said it wasn’t complicated? this video is super over-simplified too?

[@esmesa5642]

Blocky Dogy for you maybe, it’s still a lot to take in

[@blockydogy1188]

@@esmesa5642 ok yeah mood

[@Mylkzi]

Everyone here is cramming for AP biology but I’m just cramming for normal biology how is this fair

[@lu-gc7gm]

Milkywolf Z RIGHT

[@rockylowenthal2472]

heyyyy same

[@abigaila1131]

i love pre ap bio hhahahahah ha ha :(

[@pattyfarinas803]

I LOVE pre-ap bio... ha... ha ha **(flashbacks of hearing complicated words in class, zoning out and cramming like crazy the day before the exam)**

[@angelmontelongo5822]

@Nati Tesfaye me too😂😂

[@sabrinajusino6866]

I failed Biology 3 times already, this is my 4th time taking the class. First time actually trying to seriously understand it. I’ve been watching your videos that relate to what we’re learning in class, I want to thank you for helping me earn a 92% on my first exam. I’m so grateful for you!

[@roganvanaswegen4737]

RIP to the people who are watching these videos who have tests the next day...

[@oragamiboxesandmore8478]

more like today

[@fredmorais99]

More like Right now

[@fredmorais99]

More like Right now

[@imeldarashidian386]

+frederick thelen same

[@TheMrArtmaster]

yup

[@beuyhs1000]

Summary for those whom it may concern: We begin in PS2 (photosystem 2), light energy absorbed by the cholorophyll exciting electrons in it. Excited electrons move up to a higher energy level. Excited electrons move to electrons carriers forming electron transport chain (redox reactions occur). Energy is lost from electrons moving down the electron transport chain. Water is split into H+, e- and 1/2 O2 by photolysis (light energy used to break it down). Electron from the water being split is given back to PS2. Energy lost from electrons moving down electron transport chain is used to pump H+ into thylakoid from the stroma creating proton gradient. Protons move out of thylakoid down concentration gradient through ATP Synthase. Energy from this movement is used to add inorganic phosphate to ADP forming ATP. PS1: Light energy absorbed by chlorophyll exciting electrons to a higher energy level. Electron transferred to NADP along with a H+ from stroma to form reduced NADP (NADPH). - Cyclic photophosphorylation: Electrons excited by energy absorbed and passed onto electron carriers. Electrons passed back to PS1 (hence 'Cyclic')- no electrons lost)). H+ pumped into thylakoid from stroma by energy lost from electrons moving down energy levels. Proton gradient used causes high concentration of H+ in thylakoid to reduce by H+ leaving through ATP Synthase. Energy from this movement allows ---> ADP+P(i)-->ATP. NADPH and ATP used in light independant reactions.

[@MS-jf5fi]

OMG thank you so much now I may pass my test!!!

[@beuyhs1000]

Happy I could help :)

[@rainynights5139]

you made it easier thanks

[@academicthot2727]

thx bih

[@kmayflowerr]

You are a life savor!!!

[@jayy1208]

Basically the video in text, hopefully to further your understanding. Requires water (H2O), carbon dioxide (CO2) and light. Roots of plants absorb water and transport it to the leaves through xylem, CO2 enters the plant (while O2 exits) through microscopic pores in leaves called stomata, and individual photons are absorbed from the sun in the plant by the pigment chlorophyll. **It is important that O2 levels remain low (explained later) for the Calvin Cycle (Stage 2) Inside the cell of plants are plastids called chloroplasts, which contain thylakoids (which store chlorophyll), which contain lumen inside and Stroma outside; stacks of thylakoids are called grana. Light Dependent Reactions (Stage 1) PS II (wavelength p680) -Photons strike the chlorophyll in Photosystem 2 (PS II) and an electron absorbs the energy and becomes excited (photoexcitation), but has nothing to do with this energy. -The electron travels from PS II (1st protein complex of 4) along the Electron Transport Chain (via mobile electron carriers) to harness the energy; across a series of reactions the electrons lose their energy. -The energised electrons from PS II that were picked up by electron carriers are transported to the 2nd protein complex, the Cytochrome Complex. -The cytochrome complex stands in between PS II and PS I (which are all embedded in the thylakoid membrane), and uses the lost energy from the electrons to pump hydrogen ions into the thylakoid.-Now missing an electron, the chlorophyll molecule will split a H20 molecule in cooperation with PS II to steal its electron and replenish the one it lost, the by-products of this process are hydrogen ions (single protons) and oxygen. **By-product of oxygen is the reason behind the survival of living organisms. -Protons accumulated from the splitting of H2O and via the cytochrome complex now in the thylakoid then move towards the enzyme ATP Synthase, which uses that energy to pack an inorganic phosphate (Pi) onto ADP to create ATP. PS I (wavelength p700) The 'tired' electrons becomes reenergised by some photons as it reaches Photosystem 1 (PS I) and travels on another electron carrier, where all of the energy is used to help make NADPH (similar to ATP) by an enzyme, which combines 2 electrons and 1 Hydrogen ion with NADP+. (NADP+ + 2 e- + 1 H+ = NADPH). **Products of light dependent reactions: Chemical energy in the form of ATP and NADPH, as well as the by-product O2. Light Independent Reactions/Calvin Cycle (Stage 2) **Doesn't require light energy from photons, uses energy derived from ATP and NADPH to fuel processes Carbon Fixation (1st phase of Calvin Cycle) -Begins in the Stroma (empty space of chloroplast). Involves fixing a CO2 molecule onto Ribulose-Biphosphate or RuBP (the starting and end point of the 'cycle'), with the help of an enzyme called RuBisCo (which converts inorganic carbon into organic carbon), which causes it to become unstable. -So this new 6-Carbon chain has to break apart, creating 2 molecules of 3-Phopshoglycerate, which occurs to 3 molecules of RuBP (explained later). **If RuBisCo reacts with O2 instead of CO2, it creates a toxic by-product known as phosphogycolate (process of photorespiration) believed to alter enzymatic functions. Reduction (2nd phase) -ATP combines a phosphate group onto the 3-Phosphoglycerate molecules and then NADPH packs some electrons, creating 2 molecules of Glyceraldehyde 3-Phosphate (G3P). -G3P is a high-energy, 3-carbon compound that plants can convert into many carbohydrates such as glucose, or cellulose or starch. Regeneration (3rd and last phase) -9 ATP molecules and 6 NADPHs are required to convert the 3 RuBPs started with into 6 G3Ps, however only 1 G3P can leave the cycle - with the other 5 G3Ps needed to regenerate the original 3 RuBPs, completing 1 round of the cycle. **G3P is considered the ultimate product of photosynthesis as the glucose gained from it is the energy used by all cells.

[@thinudex100]

Boston You, sir, are a gift to the world. Thank you so much.

[@emilysabinas6879]

Boston thank you

[@jacobbeach2340]

Boston It all makes sense now...

[@sy8445]

you are an absolute god sent

[@insertnamhere568]

Boston Thank you! :)

[@jadaok888]

Watching this the day before my bio exam and realizing that I’m so gonna fail

[@SA71104]

Jada Ok same here

[@MiguelCPR]

@@SA71104 same :,v

[@reemalamassi3494]

me tooooooooooooooooooooooooo lol

[@stellablest9819]

me too

[@Orholam5]

aww, it's ok not everyone needs to be a scientist

[@ria-qj6hz]

"Or more likely you want to do well on your test." Pffffttt. At this point I just want to pass.

[@Momofgirls2124]

i totally agree

[@jakemorales474]

who woudnt want to pass

[@chloroplast8611]

FINALLY I WATCHED IT 34 TIMES FROM THE PAST 2 WEEKS AND I UNDERSTAND EVERYTHING except the parts after the co2 molecule gets stuck to that long chain thing. I cant believe it. I dont understand myself. and btw i am NOT just a huge sac of chlorophyl. I cant believe people keep thinking my chemicals are bad. You are all lucky you even have some energy you can digest and store as fat or use the carbs that we work so hard on maintaining and building for your quick sources of energy As soon as i find a replacement for oxygen you humans will pay for this AND WOULD YOU PLEASE STOP CUTTING THE TREES DOWN!!! Why dont you humans just move to outerspace since you think your so much smarter than us. We were here first. btw and evolution is the only real creator. ~the Chloroplast

[@jaiward4869]

tbh

[@baba_bushido]

Aquatic Marshmallow no not a chans

[@meganriley5803]

*hears a bunch of complicated words* *zones out* *freaks out and restarts the video*

[@puteriiman9162]

The4thMusketeer Ω Repeat

[@whhe11]

Sakura Miraii Why the ohm sign?

[@puteriiman9162]

It's his name

[@meganriley5803]

I'm a she, but yes that was part of my old username. It's called an omega. It's part of the Greek alphabet.

[@whhe11]

Twenty Øne Veiled Killjøys Crying! At the Discø Okay cool i was wondering what it was outside of electrical stuff.

[@arkexemption6983]

Good luck to everyone on their exam tomorrow! Now stop reading comments and get back to revision

[@madihatasnim6971]

advice taken.

[@kentcc]

i needed this lol

[@luckiestgirlintown5598]

Thank you needed that!

[@multiversalman4270]

We shall watch your career with great interest.

[@jakeisolda5234]

shut up let me procrastinate

[@notwanheda9056]

This is probably the first crash course video that I've watched and then felt MORE nervous for my exam afterward

[@bagginn]

For the lazy :D GL on tests! Photosystem II captures and transfers energy. 1) chlorophyll absorbs energy from sunlight 2) energized electrons enter electron transport chain 3) water molecules are split 4) oxygen is released as waste 5 )hydrogen ions are transported across thylakoid membrane 6) Photosystem I captures energy and produces energy-carrying molecules. 7) chlorophyll absorbs energy from sunlight 8) energized electrons are used to make NADPH 9) NADPH is transferred to light-independent reactions

[@bagginn]

Photosystem I captures energy and produces energy-carrying molecules. 1) chlorophyll absorbs energy from sunlight 2) energized electrons are used to make NADPH 3) NADPH is transferred to light-independent reactions

[@alastor2745]

Thanks bro

[@vladbob5666]

Thanks

[@MintyParasol]

thanks I have test tomoriw

[@babyjackiekpopfangirluwu3430]

Delairium, thx! I am a very lazy 5th grader that can’t do the process of photosynthesis.

[@undergroundskeptic2916]

*Replays video more than 1000 times* *Still doesn't get photosynthesis*

[@AnNguyen-kz6gd]

same

[@Noname-rh7tf]

me too

[@khaliddvidal7381]

lmao

[@chilling_muser]

watch khan acedemy's video

[@undergroundskeptic2916]

You think 2 months and 11 days after I've made this comment, I haven't figured that out already? lol. And it's spelled as 'academy'.

[@alamisc]

currently crying in bed at 3am trying to study for my AP Bio test but every single drop of will and motivation has been drained out of me.

[@stegosaurusstudios401]

did you survive

[@elizabethgentry8253]

hello

[@mcj9917]

anam ahmed i got a 30 and 45 on two of my four tests, you’re probably doing better than me

[@mcj9917]

anam ahmed and i was happy about getting a 54 on another one

[@Someone-sq8im]

Weak. I’m in 7th grade and this bores me.

[@jessicali9673]

95% of comments: studying/cramming for test 3% of comments: a summary(?) of the vid 1.99999999% of comments: some kind of thanks or 'you get me' to hank 0.00000001% of comments: this one

[@AlexisGelinas]

How in the hell did we figure this out?

[@ThePureLegend95]

Sometimes, humans even suprise themselves... ^^

[@michaelfolk888]

From dedicated scientist who spend years and years and years of hardcore scientific research. It's beautiful :)

[@LucaDeflorian222]

With an electron microscope and a lot of patience

[@NeonsStyleHD]

alberto trillo No. An Electron microscope is great for showing what things look like, but it's completely hopeless at showing us how things work. In order for an EMS to take a photo at all, the thing being photographed has to be killed, frozen solid and broken into tiny slices

[@LucaDeflorian222]

NeonsStyle My bad, I wrote a superficial comment ;)

[@sarahholland5980]

guess who's cramming for finals? me

[@ryancooper3440]

+Sarah Holland twinzies

[@andrescelano4179]

+Ryan Cooper mine tomorrow

[@pocholopan.983]

+Sarah Holland Finals Week The stress awakens I have a Ib bio exam tom. :(

[@DylanDalal]

+Pocholo Pan. same!! tomorrow!!

[@sabihah]

+Sarah Holland Same bruh

[@quantumcrash7266]

I have my test in an hour. So far I know electrons are involved somehow.

[@Someone-sq8im]

Weak. I’m in 7th grade and this bores me.

[@lizbethreynoso9044]

Someone404 why are you even here then 💀 you’re in middle school you don’t need to know all of this yet

[@adie._.8261]

@@Someone-sq8im Been using crash course since 3rd grade. Nerd power

[@adie._.8261]

Did you pass?

[@adie._.8261]

@@lizbethreynoso9044 It is not about what you NEED to know. We learn to broaden our cultural horizons, to open our minds and, to enjoy life. The saying 'Knowledge is Power', is in no way metaphorical.

[@MariaRodriguez-zv9wt]

" you are committed to having a better, deeper understanding of our world; or more probably you'd like to do good on your test" hahahaha this Hank guy is the best

[@benbrune9546]

hahahahahahhahahahahahahaghahahaha

[@arynhaleyy]

who else is cramming the night before ap bio exam

[@xlnc9627]

✋

[@Effrenatus]

cramming 5 minutes before the ap exam

[@matthewbierwirth7645]

I'm cramming for pre ap bio final

[@j-zenberg4181]

yup

[@j-zenberg4181]

yup

[@TheMarciahhh]

Hank, you and the Crash Course team are saving my butt right now! I've got a biology test tomorrow and my teacher has one of those voices that the brain tunes out ALL OF THE TIME. Thanks for making these! SO helpful!

[@elenavacaroaia9416]

i know what u mean :PP

[@cplusplushater]

"or more likley you'd like to do well on your test" I feel attacked right now this is the exact reason i'm here

[@dworf_4299]

Almost everybody here is for this reason

[@chloroplast8611]

FINALLY I WATCHED IT 34 TIMES FROM THE PAST 2 WEEKS AND I UNDERSTAND EVERYTHING except the parts after the co2 molecule gets stuck to that long chain thing. I cant believe it. I dont understand myself. and btw i am NOT just a huge sac of chlorophyl. I cant believe people keep thinking my chemicals are bad. You are all lucky you even have some energy you can digest and store as fat or use the carbs that we work so hard on maintaining and building for your quick sources of energy As soon as i find a replacement for oxygen you humans will pay for this AND WOULD YOU PLEASE STOP CUTTING THE TREES DOWN!!! Why dont you humans just move to outerspace since you think your so much smarter than us. We were here first. btw and evolution is the only real creator. ~the Chloroplast

[@JoshuaParkk]

I need to watch this again in 0.75x speed man

[@pinklerana3079]

Thats exactly what I do mate, it works though

[@siridhadesugur3697]

omg thanks for the suggestion

[@zakiyahzakir8613]

Lol i watch it at a speed of 1.5x

[@Faiyaz7]

i usually do to but im cramming so im playing it 1.75x to actually finish all vids cause its like 1 am and my finals are tmrw

[@kaisetterington4022]

HE TALKS SO FAST

[@shannonjade8672]

I got a 93% on my test today thank you so much

[@NotYourCipher]

What, my parents would kill me if I brought 96%

[@TheAshX]

Why do i even go to college? This channel teaches me more in ten minutes than my professor teaches in one semester. Crash Course explains the material thoroughly, and in a simple, concise manner, while most professors simply lecture because they are required to teach a course if the university is funding their research.

[@Krazycutiegurlxxx]

+Ashten Pickens With crashcourse though, you gotta put that video speed at 0.5. 10 minute video? If you get through all of these in the time they actually are, you miss mostly everything unless you already know the material and just want to review. But, even if a 10 minute video takes 30 minutes to watch and take notes on, it's still a lot of covered bases in a short amount of time. So, i agree.

[@ClavinTheCat]

+Hero✩Lydragius lol, I put mine at 1.5 (I watch all my videos on 2x)

[@Krazycutiegurlxxx]

Don McDermott Do you actually retain the info that way? Are you just watching or review, or to actually learn this stuff for the first time? I've been learning this for the first time and taking notes i mentioned and stuff. He talks pretty fast and i hate pausing all the time, so slowing it down makes it easier to take the notes. Also, Hank sounds hilarious at 0.5 speed.

[@ClavinTheCat]

Hero✩Lydragius yeah. I can spew that shit out like a baby spews vomit. I'm set for midterm and finals that includes any of what this guy has said. Then again, before I did this, I was the kid in classes who would shout out answers in review "while others took notes" and now I'm shouting out this stuff b4 we get to it

[@Krazycutiegurlxxx]

Don McDermott That's just what happens when you've heard it all before already.

[@pmjbnbjmp]

When Hank Green can teach you more about photosynthesis in 13min than your actual biology teacher can teach you in three weeks.

[@kanchanmukherjee9585]

Or 2 years lol

[@SydneyTheSad]

Who dislikes a video of a man trying to help students with their studies lol

[@minniemouse5185]

Students who do not want to study... Like DUH..😐😐😑😑😑😐

[@suicidalslut2485]

@@minniemouse5185 ​ Minnie Mouse Then they're not even students then.... Like DUH 😐😐😑😑😑😐

[@thelegendaryluxray6088]

Wish me luck on my giant bio exam tomorrow!!! *Cries*

[@sumikhan6959]

Good luck!

[@thelegendaryluxray6088]

Sumi Khan I got an 89% YAY

[@sumikhan6959]

Congrats!! 🎉

[@thelegendaryluxray6088]

Sumi Khan Thanks!

[@hada9901]

+The Legendary Luxray I don't get why, this is only 1/8 of our exam tomorrow. And I am not even sure that this part will come out of the test ._. fuck life

[@lucia5227]

ATP is daddy

[@vjorp5332]

Yup

[@triskx5098]

Nikki Pontius h

[@ExceptionallyUndersizedThanos]

Crab daddy > ATP daddy

[@babyboyce6017]

Just to let yall know. I am not having fun doing bio hw

[@Sam-vs6rg]

thank you for that because.. same 🦕🧪

[@anadead2838]

Am I the only one who cracks up at this man's jokes? I'm literally dying 😂

[@nigelsilla27]

Ana Dead yes

[@melbabraithwaite9350]

True

[@nephdrummond3168]

One, you’re not the only one, he’s pretty great. Two, duh, they probably have an episode about that

[@genericchannel126]

CRINGE ❗️😷

[@AnonYmous-ob7py]

I normally just watch another video when he gets too joke heavy. Its annoying af.

[@faeofthewild6818]

I remember making a model of the chloroplast for 9th-grade biology and I made it of mint Oreos, green-dyed vanilla frosting, Chocolate frosting, sprinkles, and tableware. It was everyone's favorite because we got to eat my project.

[@tomkrys3331]

"Or more probably, you want to do well on your test". Yeah pretty much Edited: 8 years old and A Level biologists are still using it to teach themselves photosynthesis. You're still a freaking legend mate

[@JohnnyGarman]

Watching Hank is like watching Khan at 2x speed.

[@whhe11]

Johnny Yeah with kahn you gotta put the video at extra speed with hank sometimes you gotta slow it down lol

[@ruyasatpathy1237]

I appreciate how deeply he understands our pain😶

[@NoorAldayeh]

me: *has a bio final tomorrow* me: opens door to room me: opens desktop me: *typing into youtube* C'MON CRASHCOURSE! hank: or more probably you'd like to do well on your test me, actually out loud: YOU GET ME HANK

[@multiversalman4270]

We will watch your career with interest.

[@jerryfan8378]

Also you: typing into comments . . .

[@benbrune9546]

that wasn't that funny

[@Safa-mx8gd]

HANK GETS ALL OF US

[@sheaelliott942]

I was so excited, my biology teacher showed this to my class, and I literally fangirled because I love Hank. He's a really good teacher and I've just been having a lot of trouble this whole year trying to understand biology in general. Now I know that I really should just crash course my material before the test, because this is easier to understand.

[@adrienes.9400]

All the shade he is throwing at plants in this video is making my late night studying so much more enjoyable.

[@trickz2795]

If he throwing shade at plants, how are they gonna do them light dependent reactions?!

[@leilanicabrera2793]

It took me 90 minutes to watch a 13-minute video and take a few notes so I could actually understand everything HAHAHA imma go laugh and cry at and with myself now.

[@olumideayeni6347]

#LastMinuteAPBioKids

[@vjorp5332]

A?

[@chloroplast8611]

FINALLY I WATCHED IT 34 TIMES FROM THE PAST 2 WEEKS AND I UNDERSTAND EVERYTHING except the parts after the co2 molecule gets stuck to that long chain thing. I cant believe it. I dont understand myself. and btw i am NOT just a huge sac of chlorophyl. I cant believe people keep thinking my chemicals are bad. You are all lucky you even have some energy you can digest and store as fat or use the carbs that we work so hard on maintaining and building for your quick sources of energy As soon as i find a replacement for oxygen you humans will pay for this AND WOULD YOU PLEASE STOP CUTTING THE TREES DOWN!!! Why dont you humans just move to outerspace since you think your so much smarter than us. We were here first. btw and evolution is the only real creator. ~the Chloroplast

[@rockylowenthal2472]

yes

[@p3arldiv3r]

MY TEST IS TOMORROW YOU'RE NOT WRONG AGGGG

[@cianarossano6950]

YES my exam is tomorrow and im freaking tf out lol

[@justalittleguy733]

"atp: the big daddy of cellular energy" LMAO

[@nochannelaccess9461]

Clogs

[@benbrune9546]

that's kinda innapropriate \

[@qusshim7463]

Wish me my luck yall, got a AP bio exam tomorrow

[@1075Rah]

+Gramed Romeo I have one tomorrow too. Dear god, this is going to be on jam packed AP Bio National Exam.

[@madow100000]

+Gramed Romeo Same it's like National Bio exam day tommorow

[@1075Rah]

They've planned it! If they coordinate another attack, ALL GPA IS LOST!

[@AidanGames]

+Gramed Romeo How'd it go?

[@qusshim7463]

AidanGames got a A-!!!!!!!!!!!!!!!!!!!!!

[@Official_Miguel_Rios]

No matter how much I read my book and rewatch these videos, nothing sticks to my head and i continue to fail my biology...... I had tried my best :( well anyone having midterms, test, etc... I wish you the best of luck!

[@jayb1797]

Anyone else cramming for a Biology Test tommorow on Calvin cycle and all things photosynthesis I hope this explains electron transport carriers for me

[@rockylowenthal2472]

same

[@dd1987x]

My grade 12 biology teacher has been using your videos in class and it's amazing. I've been a fan of CrashCourse and SciShow for years so it really makes those vital classes more fun! Thanks you guys 😁💖🤜

[@MikeHuntIsFloppy]

In your animations, can you start to label the different things? They're kinda hard to follow when I have no idea what any of the littler orbs represent..

[@thereligionofryden8521]

The AP exam is tomorrow and Hank Green is the only reason I'm gonna pass

[@broadwayhufflepuff3312]

The Religion Of Ryden It’s nice to know we’re all suffering together

[@rehorstfamily3155]

Indeed

[@rydonwunali]

1hr before a test and a beam of light magically appears and is now fixated on me. That miracle is Crash course

[@kaileynewel2180]

My exam is in 2 hours and I'm just starting this now. Thank you, Crash Course!!

[@veralozada5210]

Why do i even bother going to school? I spend hours listening to lectures and watching slides and not understanding a thing while crash course needs just 13 miserable minutes to do the job. Jeez

[@conniesblankpages3656]

Haha lol I think the same

[@kylewolfe_]

Because those lectures familiarize you with the material, even if you don't completely understand it. That's why videos like these seem so much more effective, it's because you're studying something that you've already been introduced to. I know it's easy to pass your professors off as being useless, but they deserve at least the credit of presenting the material to you.

[@multiversalman4270]

"Think about how chlorophyll feels." I have some advice for chlorophyll: Give in to your hate, your suffering, your anger, and turn to the dark side. Dark Plantaeus, welcome to the Sith! Now, rise as my new apprentice!

[@multiversalman4270]

Where Lord Vader failed, you shall rebound and rise, bringing my Empire to glory and order to the Galaxy!

[@diooverheaven1773]

I’ve got nothing to say

[@sarabara9696]

Hank Green, I just might pass my biology test in the morning because of you.

[@TheBlaze4000]

Are you British or American? It's not test..it's midterm. Got that bitch?

[@mattywatt4754]

Grant S this youtube comments suck is the most anoying closet sufferer i have ever saw we all should campain and make him just come out and stop all the abuse he gives hes well known for this you can tell hes a sad boy

[@user-xn4yu5rn9q]

*Thanos snaps* PSII disappears, no more photosynthesis, no more life

[@scisarah3770]

This was golden, thank you.

[@comradedennis8202]

Damn

[@audreyandremington5265]

Thanos snaps, half of all bacteria in humans' guts disappear. Every human dies of indigestion.

[@benbrune9546]

amen

[@brandonkim8423]

I swear you are the only reason why I am passing Honors Bio

[@keyagupta235]

*THE BIG DADDY OF CELLULAR ENERGY*

[@nochannelaccess9461]

Hilarious, innit

[@emmagustavson4819]

A moment of gratitude for Hank Green for the hope of a decent grade on my exam tomorrow.

[@LiveFabulousForever]

graduation speech: "I would like to thank spell-check and hank green"

[@estefanolivares4159]

If you teach the full name like a spell it makes it fun to say "Plastoquinone Oxidoreductase" It's one of four advanced light spells created by aurors during the rise of Voldemort to counteract his death eaters

[@afshanafzaly7502]

+Estefan Olivares What are the other three mate?? I'd say one is Lumos, cept its not very helpful in catching death eaters

[@estefanolivares4159]

+Afshan Afzaly Lumos isn't a very effective offensive spell, but Ramos Tesla did expand the Lumos spell with Luminol which casts a light on the object you were looking for, a spell that isn't much used thanks to the Accio spell, but still useful if you forget what you were looking for. Chemiluminescence is a powerful area of effect spell that can burn and temporarily blind enemy wizards. Fiat Lux is the next spell and it fires a concentrated beam of light which can knock back an opponent back several meters. The final spell is Libertas Perfundet Omnia Luce. This spell may seem similar to a patronus in that it creates a light based object that the user can wield, but the wizard or witch can choose what to create and are not limited to animate objects

[@luciadhopulli5884]

+Estefan Olivares you're my type of person.

[@Omaaargod]

+Estefan Olivares This took more brain power than the video XD

[@thegivingtree887]

You're a legend. Please accept my cookie. 🍪

[@peachybunny.]

Who watched the whole thing like 3 times and still had no idea how photosynthesis works

[@rednax-9940]

#CrammingForAPBio

[@laserbunny979]

same

[@isalia7932]

Same

[@ambermclaren1222]

Logan Alexander Me rn

[@artisanallyph]

i have PreAP but i think it counts

[@zsuzsakiss210]

how does hank explain this to me in a way that i can understand in less then 15 min while my bio teacher has spent a total of 4 periods or 3 hours trying to teach us this but still no one has a clue what is going on? thank u so much this channel is saving my bio grade.

[@navaldude92]

I laughed so hard when he was talking about the 12 year old girls moms shouting "HOW DO I FIX THIS PROBLEM?" LOL

[@habibabadran1463]

lol same but its funnier for me cause ive been ubducted too but from what? KPOP THATS WHAT (my spelling is not the best)

[@lampje5185]

Also like, the solution was to make a new child instead of getting the old one back. Like eh you win some you lose some.

[@melbabraithwaite9350]

True ha ha

[@daylxght8055]

@@habibabadran1463 That's exactly what I put in the scenario lol ! BTS ARMY !! Who do you stan ?

[@morkswatermelon7180]

@@daylxght8055 i litterally cant count

[@chocolatuyu8039]

I have a midterm in 1 HR and here I am

[@ishratsingh8365]

This photosynthesis stuff is so confusing...thanks Hank for all your help, but I'm still feeling really queasy about my Bio quiz tomorrow...

[@erinuhelski8538]

Preach

[@SprinklesForThePeeps]

Haha yass

[@SunlightHugger]

Great video, mate. You just explained in 13 minutes what it's taking my professor a week to go over in the same detail. I like that very much.

[@quannarula7046]

This video was a lot more enjoyable to watch when I didn't have a test the next day

[@Sam-vs6rg]

5:52 thank you for this iconic moment hank, thank you !!

[@saraahmad7579]

AP Bio midterm anyone? Lol I couldn't stand the textbook and this guy teaches better than my real teacher ever has!

[@LastingHeart715]

well....I'm screwed for biology exam tomorrow.....

[@OtterOnTheDaedalus]

LastingHeart715 Hope it went well!

[@FROPDESAI]

LastingHeart715 Give us an update!

[@89fulrami]

u fail?

[@hellokittyhi9403]

Might fail too

[@khyberrsr3921]

+LastingHeart715 In the same boat....

[@sgchesney]

Okay guys if you're craming (like I normally am when watching these) turn on closed captions (CC button, select your language), they help you focus and understand what he's saying and they're great for if you're writing notes too Hope you do well on your test!

[@sers6561]

Your sarcasm is absolutely off the charts... im loving it

[@k80_]

THANK YOU SO MUCH!!! ITS THE NIGHT BEFORE FINALS AND YOU EXPLAINED IT BETTER IN 13 MINUTES THAN MY TEACHER DID IN SEVERAL WEEKS OF CLASSES😅

[@Vanditha-th8oc]

me: why photosystem ll? hank: oh do you want the full name? me: *hears the name* photosystem ll it its!!!!

[@apop2014]

Hank Green is making me feel bad for hurting chlorophyll's feelings lol! But still glad for this series! It helps me so much in school.

[@prabhleenreen3594]

this is actually one of the best photosynthesis videos ever you just need to prep a little beforehand to understand it

[@smol_chilli_pepper]

4:55 the analogy with the mother chlorophyll freaking out about losing her electron gets kind of dark cause then to fix the problem she steals someone else's child.

[@micaelcarestiato]

Haha that's true

[@chillicub0330]

+1210Nique hahaha I was thinking the same thing

[@DinaKubba]

I just started revising Photosynthesis for my AP Bio exam tomorrow, I'm doomed.

[@pogchamp6416]

+Light Yagami how did you do, we are just starting this section

[@DinaKubba]

+DmndMinecrafter I actually did very well, and I got the highest grade in the class.

[@DeTomboy4]

+Light Yagami Mine's tomorrow.

[@jala2765]

+Light Yagami YOU'VE COME BACK (SPOILER) FROM THE DEAD!!!!!!!!!!!THANK GOD I THOUGHT YOU REALLY WERE GONE

[@clashclan4645]

+Light Yagami Doesn't sound like you were "doomed" to me. Maybe you should reserve that term for more "dire" circumstances

[@niksdee]

Those catty remarks about RUBisCO and its inefficiency made this so much fun to watch Crash course never disappoints :D

[@allisonmaguire2489]

God bless you CrashCourse for helping me grasp concepts that my teachers have failed to help me understand.

[@eghosab13_]

Watching for my exam tmrw PRAY FOR ME!!

[@dc2008242]

I came to learn a little bit more about photosynthesis.... I see a bunch of people complaining about religion & science, I mean really??? WHAT DOES RELIGION HAVE TO DO WITH PHOTOSYNTHESIZING?!????!?!?

[@matheusribeiro8523]

Because people think that the complexity of phtosynthesis is impossible to be achieved through evolution, which, in the end, is just saying: I can't understand (or i find it difficult/complex) so it must be magic.

[@matheusribeiro8523]

And then atheists were complaining about that and religion and everything, because you know, they pretty much complain about everything (atheist here).

[@dc2008242]

Matheus Ribeiro XD, I love your response, both enlightening and entertaining

[@matheusribeiro8523]

Thank you! :)

[@jessieellen7914]

Yeah I mean I love science but I also love God 😄

[@astolfo9377]

The dislikes are GCSE students who dont get this because all they have to learn is carbon dioxide + water + light energy → carbohydrate + oxygen LOL

[@clevelangdale]

Could be people who are wondering why he said photosynthesis developed 450 million years ago in the intro. Hope that's not on anyone's test.

[@dawittewelde1866]

thank..... i have being watching this channel since i was 7th grade and it never let me down, keep it up. please

[@julailuke]

He really gets to the point. Great for reading notes.

[@Chazzberg]

for my exam i don’t need every single bit of detail in this video but it helps a ton still

[@jorialjiran3362]

0:17-0:23 he admitted it I don't think even teachers would deny it

[@Directioner171]

Never have I ever been so thankful for a video in my entire life. Thank you, Crash Course!

[@AmazingTNT]

Recommended by teacher to watch this... funny, because I'm subscribed to you guys! Great videos, keep up the great work!

[@MaryamKhan-zb9hm]

We're about to take a test in about 30 minutes May we RIP

[@YOSHIMOTO_HI_SPEED]

How'd it go?

[@YangMasterJ]

Thanks for this video! I was the only one in my class that passed the Photosynthesis test in my Biology class :)

[@mossara7898]

I’m a peer tutor.... this alone helped me make a concise set of notes for my class. Thanks crash course I love u

[@samridhisemwal5841]

*turns on captions* *changes speed to 0.25* ME: Photosynthesis? What's that?

[@uhbeel]

Studying for my Biology Honors Semester Exam... Yay!? 0.o

[@andres16251]

this is too much information at once....... It would be helpful if u summarized each thing at the end so I can understand it better..........PLEASE

[@zarapoole9457]

After such a speedy and full on lesson last week and then being told that I have a test tomorrow... the saviour that is crash course is here to save me... I will forever thankyou and all of your amazing videos!!!!!!!