Since the animations are kinda confusing the numbers up, I recapped the transformation here: *Glycolysis* Glucose + 2 ATP >> 2 Pyruvates + Energy. This energy is used for making 4 ATP (net profit of 2 ATP) and 2 NADH from 2 ADP, 2 NAD+ and 2 hydrogen (probably H+). *Fermentation* Pyruvate >> Energy + Lactic Acid. *Krebs Cycle* 2 Pyruvates + 2 O₂ >> 2 Acetyl Coenzyme A + 2 CO₂ + Energy. This energy is used to form 2 NADH from NAD+ and hydrogen. 2 Acetyl Coenzyme A + 2 Oxaloacetic Acid >> 2 Citric Acid. 2 Citric Acid + 4 O₂ >> 2 Oxaloacetic Acid + Energy + 4 CO₂. This energy is used to make 2 ATP, 6 NADH and 2 FADH₂. So after the Krebs Cycle we now have 10 NADH, 2 FADH₂ and 4 ATP (or 6 if you count the ATP spent in Glycolysis). *Electron Transport Chain* 10 NADH >> Energy + 10 NAD+ + 10 Hydrogen. This energy is used to pump some protons out of the inner membrane of the mitochondria. They went back through the ATP synthase creating at most 3 ATP for each NADH, for a total of 30 ATP (at most). 2 FADH₂ >> Energy + 2 FAD+ + 4 Hydrogen. This energy is also used to pump some protons. This creates, at most, 2 ATP each FADH₂, for a total of 4 ATP. _Conclusion:_ _Total ATP created: 38 molecules, if the cell is very efficient._ _2 ATP is spent in glycolysis so there would be at most 40 ATP that went through the steps._ _10 NAD+ were used, and probably reused._ _2 FAD+ were used, and also probably reused._ _6 O₂ were used and they became 6 CO₂ in the Krebs Cycle._ _2 Oxaloacetic Acid were used and reused._ Hope this helps!
so basically its complicated, a glucose (a simple suger) is cut up and bits and pieces make energized molecules such as NADH. These energized molecules shove protons (+H) to the other side of the mitocondrial membrane and whem they want to come back in they are squished together with a phospate and a ADP (adenesize DIphosphate) to essetially make ATP. hope this helps :>
idk if this will still help, but i totally recommend amoeba sisters, a biology youtube channel. i think it goes a bit slower, and doesn’t go as in depth, but gives a general outline of things
KingOfShenanigans aaaaaaaaaah no. keep reading r-e-a-d-i-n-g...a study of present-day mitochondrial DNA, combined with evidence based on physical anthropology of archaic specimens. According to genetic and fossil evidence, archaic Homo sapiens evolved to anatomically modern humans solely in Africa, between 200,000 and 100,000 years ago,
To everybody out there struggling with this: don't give up! Do not underestimate how much it helps to slowly watch the video bit by bit, over and over. I had to do this quite a few times, but I feel like I've finally got the hang of this. You can do it! And thanks to Hank and the team!
I watch all of the crash course biology videos while studying for my biology class. While I like my instructor, he is not very descriptive about the biological processes themselves. I am always lost in class, and then have to come watch videos to see the processes, and understand. I can memorize definitions all day, but I have to see stuff in action to be able to truly understand it. Thanks guys! You are my heroes!
It might easier for you to watch the crash course videos first and then try to find a handwritten tutorial for the topic. There is a really helpful user called Handwritten Tutorials
+GodOfStrategy I saw different videos about that several times. Many in German (my primary language) and then some in English by Paul Anderson and this Chanel because I actually have to know all that stuff currently in English (year abroad). It really takes an awful looooong time to actually get all that stuff! So, yeah. I re-watched it several times.
60% of comments: How people are cramming for finals 20% of comments: People asking for prayers 15% of comments: Both of the above combined 5% or comments: Other
Antonio R Um...do you mean "The Katherine"? She was the woman standing next to him in the "In Da Club" video...though you might be right. I think she has a degree in science.
Glycolysis: Takes place in Cytoplasm is Anaerobic Breaks down Glucose into 2 pyruvate molecules, 2 NADH, and 4 atp Requires 2 ATP investment so a net gain of 2 ATP Krebs Cycle Aerobic, happens across the inner membrane of mitochondria One of the pyruvates is oxidized (combined with oxygen) and leaves the cell as CO2 What's left is a two-carbon compound called acetyl-Coenzyme A (Acetyl CoA) Then another NAD+ comes along and picks up hydrogen becoming NADH Enzymes bring together a phosphate w/ a ADP to create another ATP molecule for each pyruvate (2 ATP) Enzymes also join Acetyl CoA w/ Oxaloacetic Acid to produce citric acid The Citric acid is oxidized, cutting off carbons to prodcue oxaloacetic acid, that's why it’s a cycle Carbons are exhaled by the cell Each time carbon is removed from the citric acid it releases energy in the form of NAD+ and FAD NAD+ and FAD are electron carriers that pick up Hydrogen protons to energize the electrons Each pyruvate yields 3 NADHs and 2FADH2s per cycle and there are two pyruvates from 1 glucose Produces: 2 NADH Electron Transport Chain (ETC) Electrons in all the NADH and FADH2 provide the energy to pump Hydrogen ions across the inner membrane of mitochondria (active transport) creating a Concentration Gradient Because of the Gradient, the H protons want to cross back to the other side of the membra=ane, this forces them through a protein channel called the ATP synthase which uses the movement of the protons to spin and generate ATP Produces: 34 ATP (energy of each electron is producing about 3 ATP each Lactic Acid Fermentation: Anaerobic-only used when there is a lack of oxygen Frees up some NAD+ which create Lactic Acid Buildup Can't make much ATP Your Welcome- u should sub
hah, all these people in the comments mentioning that they are watching this the night before their exam how about watching this on the way to class? beat that plebs!
+paula lobo ikr i have a bio test on this tomorrow and these videos are a lifesaver. meanwhile my textbook is like a bible- it's beautiful, it's lifesaving as well, but dang can it be complicated to understand.
I've been going to a 2 hour lecture everyday for a week and picked up nothing about Cellular Respiration. Crash course literally taught me and helped me understand this in 13 minutes!
You are currently my hero. My textbook is terribly written and it only took 13 mins to go from struggling to understand even one cycle to 98% on my test. What would I do without you Hank.
Man, I wish Hank was my Biology teacher. My teachers made it so complicated when they were talking about ATP production in the ETC, but now I totally get it!
Hank Green is my favorite crash course teacher. Thank you for helping me become more confident in my psychology and science courses for nursing school. I'm a huge fan! You're the best, Mr. Green.
I used to watch these videos all the time in high school and they got me through AP bio my sophomore year... I took a few years off after high school (so its been a while), and now that I'm in university majoring in biology, crash course is once again saving my life - thank you!!
This is probably the most complex topic in Cell Biology. It's a little difficult to keep track of what's being broken down, what and how much is produced and most of all, how is it all produced. Thanks for the visuals and keeping this topic entertaining.
Jazzerlat45 It really does help if you just write out the whole mechanism. It really helps you understand what's going on and what's produced (and the names of the enzymes and products being created). I think oversimplifying such a complex process like this does more harm than good: it just leads to confusion. It really makes a lot of sense if you just draw the whole thing out, step by step, molecule by molecule.
Its currently 4:29 am, my test is at 11:00 and lets just say I was doing extra credit for another exam I have later today that now im finally studying for this exam and I fear it might be too late, please pray for me.😅😴
Break it down into small steps, one step at a time buddy. Review it several times. One step at a time! When you understand part 1, go to part 2. Never give up.
Having a panic attack from my bio course breezing through this and moving on in 45 min. With attention and learning issues, I must work 6x as hard to understand simple concepts. Your program has really helped me and others like myself to stay afloat. Thank you sooo very much!!
its wild cause if you choose to attend college you'll be faced with these same concepts again lol its crazy how you're probably 14-15 learning the concepts im relearning as a 19 year old lol
Despite all of the hate left on your comment log, I thought this was a very educational and entertaining explanation of respiration. The visual displays were awesome, The sound effects kept me amused and the fun facts were note worthy. I hope to see many more videos from Hank and Crash Course
My biology exam is tomorrow and I know everything now because of this video. I have this weird way of memorising things that interest me or its so visual that it stays in my mind. That is why I'm sure I will do well tomorrow. Great video! Crashcourse is the best way to study! Thanks a lot
Thanks for this great video! Some other helpful things to note that were not explicitly stated in the video: -The Krebs Cycle occurs in the inside of the inner mitochondrial membrane AKA in the mitochondrial matrix. -Another name for the Krebs Cycle/Citric Acid Cycle is the Tricarboxylic Acid (TCA) Cycle, so if you ever hear those terms, know that they all refer to the same process. -Cellular respiration occurs not only in animal cells but also in plant cells.
I still love you asapscience, but, I've found someone else... what we had together was special, in Grade 9 i nearly learnt the periodic table because of you! but crash course, well he makes me feel so smart, so ready for any quiz. I would always love you, and cherish the time we had together and maybe one day we'll get back together... I'm still going to spend time with you but I think we should see other people. I'll always love you asapscience.
For those who are wondering, a phosphoglucoisomerase is an enzyme that catalyzes the conversion of glucose-6-phosphate into fructose 6-phosphate in the second step of glycolysis.
Yeah my teacher did too! I was so excited, I've been using it for bio all year and I'm just glad that he sees it as a good resource as well. I hear too often about the evils of the internet, particularly TH-cam, killing the brains of our generation.
Mine did too! She actually posts links to these almost every week! I've been watching for a while, but now all my Nerdfighter high school friends freak out. ^^
Can I just add something that confused me for a while and only recently understood it. Glucose does not "produce" 32 ATP molecules. It provides the hydrogen ions to create a potential difference between the membrane which can then be used to synthesise ADP into ATP. The molecules of the ADP, ATP, and the phosphate group that breaks off/attaches on to ATP/ADP circulate around the whole system, again, they aren't "produced" by glucose alone. I was struggling over this concept for over a month before I had a deeper look into this, and thought this might benefit another person who came to this video looking for help.
+Alexander Wung You can think of it as a power plant (brace for some long physics and more chemistry). Lets take a coal plant (ignore the environment for now or lets just say that proper measures have been placed to make sure the environment gets left alone) The glucose is the raw material in the reaction like coal. Its molecules contain all the energy in the form of chemical energy. During glycolysis, energy is needed to break the bonds in the glucose molecule (like activation energy). This is why we need the initial supply of ATP, to provide the activation energy. This is like heating the coal up in order for them to burn. Once the bonds are broken, the formation of new bonds releases more energy such as the formation of pyruvate molecules and 4 ATP molecules in glycolysis. Next, the energy that remains in the pyruvate molecules is extracted. In the Kalvin cycle the energy remaining in the pyruvate is extracted but is not directly stored in the form of chemical energy in ATP yet. It is instead stored in the form of chemical energy the molecules NADH and FADH2. Back in the power plant, this is like the coals burning and releasing energy into the water around them. The energy that was stored in the coal is not converted into electricity directly, but converted into heat energy in the water, which is then utilized to get the electrical energy. Finally, we get to the electron transport chain. The energy of the NADH and FADH2 is converted into potential energy in the proton gradient (hydrogen ions concentration gradient). This new form of energy is then used to synthesize ATP as the protons flow down their gradient and activate ATP synthesase. Back in the coal plant, the heat energy is used to turn the turbine blade, the heat energy is converted into kinetic energy. the turning blade then produces energy. quit simply, glucose doesnt form ATP, but the energy stored in glucose is transferred to ATP through cellular respiration. Energy is flowing from glucose to other molecules and finally ATP.
+Alexander Wung Correct me if I'm wrong, but in glycolysis and krebs cycle, molecules derived from glucose ie. pyruvates and acetyl coA are used to make ATP. So glucose makes some ATPs while the rest are made from the potential difference. Also I'm pretty sure that anaerobic bacteria get most of their ATP from glycolysis in which glucose is broken up to directly produce ATP.
I am in A&P and found your video the only way I was able to understand this concept. Helped me tremendously for my comprehension of the subject. THANK YOU SO MUCH for making this!
Thank you for existing!!! I'm in a fast paced nursing school (as in my general studies like anatomy are very very fast paced and I can't get below an 85 in ANY of my classes or I FAIL) and we're going soooo fast I got super lost last week. (we did everything about the cell including mitosis and meiosis in less than 2 hours!) ugh. My professor even admitted it was an 8 hour class. I haven't seen this stuff since 7thh grade since I skipped high school biology. Brilliant choice. Anyways, rambling. Carry on!! Thank you!!!!!
It's crazy I keep coming back to this video: for GCSE biology, for A level Biology, for first year of uni and here I am again for a cell biology exam in third and final year of uni. V thankful to this video tbh. Impossible to long term remember respiration - too complicated lmao
I know. I have an AP Bio exam in 2 weeks so I need to get this crap down but even after watching Crash Course which I usually understand, I still feel like I'm at square one :/
I HAVE HAD 4 CLASSES TRY TO EXPLAIN TO ME WHAT YOU DID IN LESS THAN 15 MINS. this is why I watch crash course, the moment you said money my brain started to work THANK YOU
BEST WAY TO EXPLAIN A COMPLICATED PROCESS. MOST VIDEOS DON'T ACHIEVE THE GOAL. CONGRATULATIONS "CRASH COURSE"!!! Graphics, Pauses, descriptions..excellent!!
even tho i don't, but u might be because he didnt explain glycolysis, prep phase, krebs cycle and etc in detailed. there is a lot more steps in each of these(like 10). u should look up detailed explanation of these processes and then it might make more sense. good luck;)
Z Grace i know today I was looking through a PowerPoint he provided for us and I got mostly everything. The only thing that's really bothering me is the Krebs cycle.
Jorge Olivares agreed i just had a quiz on glycolysis prep phase and krebs cycle and krebs cycle is the hardest to remember in my opinion bc of all the names.....
Just saying, I'm pretty sure the Krebs Cycle occurs in the mitochondrial matrix, and not the inner membrane. I am currently in honors bio, and my teacher made it clear that glycolysis occurs in the cytoplasm, Krebs cycle occurs in the mitochondrial matrix, and oxidative phosphorylation (ETC) occurs in the inner membrane of the mitochondria.
Krebs Cycle does occur in the mitochondrial matrix HOWEVER one of its key enzymes known as "Succinate Dehydrogenase" is actually membrane bound... and it's bound to the inner mitochondrial membrane.
It's 2020 and my "Science for Teachers" instructor assigned this video and I am a happy nerdfighter for that! Will continue to use these videos in my class as a student and I'll use crash course kids when I have my own classroom one day! :D
hey guys, i really found this video extremely helpful. I want to ask if it possible that you do a more in detail video of the ATP production of the different cycles separately? I think separating the cycles will be really helpful and easier if you struggle with only one cycle. Your videos have literally helped me pass so many exams and even do well. Thank you so much.
lmTheDudeMan Well this video isn't a Lecture but more of a review and crash course on the topic. If this was a lecture, it'd be typically 30 minutes to an hour long for obvious reasons.
00:00 Cellular respiration is how we derive energy from glucose. 01:37 ATP is the currency of biological energy 03:16 ATP is minted through cellular respiration 04:44 Glycolysis generates 2 ATPs and 2 NADH 06:30 Anaerobic respiration leads to lactic acid build-up in muscles 08:13 Enzymes in the Krebs Cycle create ATP and CO2 through a complex cycle. 10:09 B vitamins Niacin and Riboflavin hold high energy electrons for later use in the Electron Transport Chain 11:44 Animal cells make ATP through cellular respiration
hi! I loved the video but I want to clarify that when we feel that our muscles are hurting it is not for the lactic acid, it's because you destroy some cells and muscles doing exercise so it's like having a bruise in your muscles. They are not used to doing a lot of work
I'm a chemistry and biology teacher and I love your videos, but I have one qualm: Energy is released when bonds are made, not when bonds are broken. It actually takes energy to break bonds, which is often portrayed incorrectly when it comes to biology and ATP. I don't have a quick fix for this, because it seems that explaining the truth of how ATP is used as "energy currency" in cells gets very complicated when you add this wrinkle. Still, just sayin, this video may be reinforcing a popular misconception. Thanks for all the videos, I really do love them.
isn't it because the breaking of ATP is an exergonic reaction, with a low activation energy, therefore releasing more energy than it takes to cause the reaction? i thought that was the explanation, I don't mean to be critical
No, you're fine Sam. There's a good chance that I'm confused about this topic, and I'm making sense of it still since having my mind blown about a year ago. I'm under the impression that breaking bonds ALWAYS requires an input of energy, and forming bonds ALWAYS releases energy. When atoms are attracted to each other to make bonds, the bonding is accompanied by a release of chemical potential energy. From what I understand, ATP is a useful molecule because, like you said, breaking the 3rd phosphate bond has a very low activation energy, but in any case breaking that bond requires an input of energy. What I'm saying is that the actual energy release that happens after, the exergonic portion of the reaction, must be a result of a later bonding event. If all of the above is true, then saying that breaking a bond in ATP releases energy is promoting an inaccurate idea by ignoring the fact that CREATING bonds releases energy. Happy to be corrected if I'm wrong.
Bill Weisberger I think it's because there is free energy released in the conversion of ATP to ADP, as the enthalpy of ATP is higher than ADP. Yes, there needs to be an input of energy in the transition state, but the free energy change makes the overall reaction exergonic. At least, that's what I've understood from two biochem lectures in med school haha!
Fun fact about ATP, if you were to take every molecule of ATP in your body you would have enough to fill up about a shotglass. It's amazing how this stuff works.
This kid is so smart and so helpful. Thank you yung blood. You just helped black man get his degree. Go to bed tonight knowing that you impact lots out us out here. Thank you.
![fellow fellow - พรุ่งนี้ไม่มีใครรู้ feat. INK WARUNTORN [OFFICIAL MV]](http://i.ytimg.com/vi/QP6JyjYx_W0/mqdefault.jpg)
The hour long complicated version with finger puppets is literally what I need.
same i have ap bio.
Same, I have college Bio
Jana ElRifai frfr IB sad bro
I was reading this comment and was like “puppets”? Then halfway thru the video.. yes... I need the puppets too.. 😂
Since the animations are kinda confusing the numbers up, I recapped the transformation here:
*Glycolysis*
Glucose + 2 ATP >> 2 Pyruvates + Energy.
This energy is used for making 4 ATP (net profit of 2 ATP) and 2 NADH from 2 ADP, 2 NAD+ and 2 hydrogen (probably H+).
*Fermentation*
Pyruvate >> Energy + Lactic Acid.
*Krebs Cycle*
2 Pyruvates + 2 O₂ >> 2 Acetyl Coenzyme A + 2 CO₂ + Energy.
This energy is used to form 2 NADH from NAD+ and hydrogen.
2 Acetyl Coenzyme A + 2 Oxaloacetic Acid >> 2 Citric Acid.
2 Citric Acid + 4 O₂ >> 2 Oxaloacetic Acid + Energy + 4 CO₂.
This energy is used to make 2 ATP, 6 NADH and 2 FADH₂.
So after the Krebs Cycle we now have 10 NADH, 2 FADH₂ and 4 ATP (or 6 if you count the ATP spent in Glycolysis).
*Electron Transport Chain*
10 NADH >> Energy + 10 NAD+ + 10 Hydrogen.
This energy is used to pump some protons out of the inner membrane of the mitochondria. They went back through the ATP synthase creating at most 3 ATP for each NADH, for a total of 30 ATP (at most).
2 FADH₂ >> Energy + 2 FAD+ + 4 Hydrogen.
This energy is also used to pump some protons. This creates, at most, 2 ATP each FADH₂, for a total of 4 ATP.
_Conclusion:_
_Total ATP created: 38 molecules, if the cell is very efficient._
_2 ATP is spent in glycolysis so there would be at most 40 ATP that went through the steps._
_10 NAD+ were used, and probably reused._
_2 FAD+ were used, and also probably reused._
_6 O₂ were used and they became 6 CO₂ in the Krebs Cycle._
_2 Oxaloacetic Acid were used and reused._
Hope this helps!
AnBio Department of Analytics thank you so much!!!!
:))))
u r amazing
bless
thank you!!!
probably should've paid attention in class... questioning life choices
Anusha Benny When you pay attention but still don’t understand 😔😔😔
This video made me cry. I understand nothing. Please help
Sis I feel you
I feel y’all 😂 I’m in the same boat
so basically its complicated, a glucose (a simple suger) is cut up and bits and pieces make energized molecules such as NADH. These energized molecules shove protons (+H) to the other side of the mitocondrial membrane and whem they want to come back in they are squished together with a phospate and a ADP (adenesize DIphosphate) to essetially make ATP. hope this helps :>
no problem :>
idk if this will still help, but i totally recommend amoeba sisters, a biology youtube channel. i think it goes a bit slower, and doesn’t go as in depth, but gives a general outline of things
I don't care what grade I'm in, I'll always resort to Crash Course to help me study for an exam
I agree gg
Cells are too complicated for their own good. Soon they will band together and become powerful enough to take over the wor-- oh wait.
Vercingetorix 39 billion*
MARK CHAN i think he or she was referring to humans, so it would only be about 20 thousand years ago.
KingOfShenanigans Errrrm... both of you got that one wrong. About 200,000 - 1,000,000 years since the earliest known Homo Sapiens.
Callum Baker i'm flammable
KingOfShenanigans aaaaaaaaaah no. keep reading r-e-a-d-i-n-g...a study of present-day mitochondrial DNA, combined with evidence based on physical anthropology of archaic specimens. According to genetic and fossil evidence, archaic Homo sapiens evolved to anatomically modern humans solely in Africa, between 200,000 and 100,000 years ago,
I’m gonna ace this test, ready guys: the miTOCHONDRIA IS THE POWERHOUSE OF THE CELL
YESSSSSS
that is literally all i know about biology
Whoa careful with the controversy lol
Umair oh ma god that’s why i got it wrong on the test 💀💀💀💀
@daddy nadine this is literally all i know about life
I wish he was my bio teacher 🤧💀😂 he makes everything so fun and easy !!! Also who has an exam tomorrow?
Going to have science quiz tomorrow thats why i am here lol
Me
I have a quiz tmrw and I don’t understand anything lol
@PANDA GIRLS how did it go?
Ella Kirkpatrick it actually went good I didn’t expect that
To everybody out there struggling with this: don't give up! Do not underestimate how much it helps to slowly watch the video bit by bit, over and over. I had to do this quite a few times, but I feel like I've finally got the hang of this. You can do it!
And thanks to Hank and the team!
I watch all of the crash course biology videos while studying for my biology class. While I like my instructor, he is not very descriptive about the biological processes themselves. I am always lost in class, and then have to come watch videos to see the processes, and understand. I can memorize definitions all day, but I have to see stuff in action to be able to truly understand it. Thanks guys! You are my heroes!
Amanda Bivens mines scatter brained and I can’t keep myself with her cause she’s all over the dang place
Anyone else zone out and have to re-watch this?
+GodOfStrategy Totally, still a good video though
For sure
+GodOfStrategy Re watched probably 6 times now. It took me that long to completely understand lol
It might easier for you to watch the crash course videos first and then try to find a handwritten tutorial for the topic. There is a really helpful user called Handwritten Tutorials
+GodOfStrategy I saw different videos about that several times. Many in German (my
primary language) and then some in English by Paul Anderson and this
Chanel because I actually have to know all that stuff currently in
English (year abroad). It really takes an awful looooong time to
actually get all that stuff! So, yeah. I re-watched it several times.
60% of comments: How people are cramming for finals
20% of comments: People asking for prayers
15% of comments: Both of the above combined
5% or comments: Other
CobraHawk 140% make it equal 100% lol
You forgot some of us don’t understand a single thing
I got 94% in my biology christmas exam!! I want Hank to be proud of me more than I want my own parents to be
I am sure he is proud of you.
Alison Good. Why would anyone even dislike these videos?
Alison his wife must be proud of you as well. Did you see his ring on his ring finger?
Alison Seems like another "by product" of Hank's videos.
Antonio R Um...do you mean "The Katherine"? She was the woman standing next to him in the "In Da Club" video...though you might be right. I think she has a degree in science.
Glycolysis:
Takes place in Cytoplasm is Anaerobic
Breaks down Glucose into 2 pyruvate molecules, 2 NADH, and 4 atp
Requires 2 ATP investment so a net gain of 2 ATP
Krebs Cycle
Aerobic, happens across the inner membrane of mitochondria
One of the pyruvates is oxidized (combined with oxygen) and leaves the cell as CO2
What's left is a two-carbon compound called acetyl-Coenzyme A (Acetyl CoA)
Then another NAD+ comes along and picks up hydrogen becoming NADH
Enzymes bring together a phosphate w/ a ADP to create another ATP molecule for each pyruvate (2 ATP)
Enzymes also join Acetyl CoA w/ Oxaloacetic Acid to produce citric acid
The Citric acid is oxidized, cutting off carbons to prodcue oxaloacetic acid, that's why it’s a cycle
Carbons are exhaled by the cell
Each time carbon is removed from the citric acid it releases energy in the form of NAD+ and FAD
NAD+ and FAD are electron carriers that pick up Hydrogen protons to energize the electrons
Each pyruvate yields 3 NADHs and 2FADH2s per cycle and there are two pyruvates from 1 glucose
Produces: 2 NADH
Electron Transport Chain (ETC)
Electrons in all the NADH and FADH2 provide the energy to pump Hydrogen ions across the inner membrane of mitochondria (active transport) creating a Concentration Gradient
Because of the Gradient, the H protons want to cross back to the other side of the membra=ane, this forces them through a protein channel called the ATP synthase which uses the movement of the protons to spin and generate ATP
Produces: 34 ATP (energy of each electron is producing about 3 ATP each
Lactic Acid Fermentation:
Anaerobic-only used when there is a lack of oxygen
Frees up some NAD+ which create Lactic Acid Buildup
Can't make much ATP
Your Welcome- u should sub
my savior
You forgot H2O
Trying to learn an entire semester of Biology in one night 🙃
me too :')
Facts💀
This is actually me this I hope u passed ur exams this is so memorable....
Ai M u mean 13 minutes
I'm trying to do two semesters... I'm definitely going to fail
Roses are red
Violets are blue
Stop reading the comments
You have work to do
Get Satisfied lmao
lol so true
word
You got me lmao
Oof he is right
hah, all these people in the comments mentioning that they are watching this the night before their exam
how about watching this on the way to class? beat that plebs!
What about watching it during class?
Beat that
Procrastination at its finest
Pfff peasant i watched it during the exam
Watching it before I ever take orgo
😂😂😂
this was a whole chapter of my book in 13 min omg i love this
+paula lobo ikr i have a bio test on this tomorrow and these videos are a lifesaver. meanwhile my textbook is like a bible- it's beautiful, it's lifesaving as well, but dang can it be complicated to understand.
+Yasmine E. Pang my bio test is today and im watching this at 4:00 in the morning desperately trying to inprove my grades
+paula lobo same i am writting a paper and the book did not cover this stuff
Yasmine E. Pang i just foumd ez notes .put cambel biology and the chapter it helps alot
Shaniya W use ez notes omg it helps
Adenosine Triphosphate: **shoots off third phosphate group**
Adenosine: "Die, Phosphate!"
😂😂😂😂
I've been going to a 2 hour lecture everyday for a week and picked up nothing about Cellular Respiration. Crash course literally taught me and helped me understand this in 13 minutes!
College Bio Exam tomorrow. Please pray for me.
Pavan Bopara Dues Vult Heathan!!!
Pavan Bopara It was a Crusader Kings 2 joke.
damn man i'm a freshman in highschool and i have to do all of this
Bro, Same, I've got midterms next week and a bio test tomorrow. I have to go here cause my teacher is just confusing me.
I have a midterm tomorrow
You are currently my hero. My textbook is terribly written and it only took 13 mins to go from struggling to understand even one cycle to 98% on my test. What would I do without you Hank.
Ah the photosynthesis and cellular respiration unit of Biology. Good luck to everyone else suffering :')
cloncar101 AJ god help me
Try Formal Logic; biology would be a walk in the park.
Pray for me
It is a very difficult unit!
doing that rn and I'm dying
It’s been 7 years and I’m gonna need that enzyme puppet show now... 😅
Man, I wish Hank was my Biology teacher. My teachers made it so complicated when they were talking about ATP production in the ETC, but now I totally get it!
He has a psychology crash course series as well, that is just as good. Hank is awesome.
Stuart? At least they try and teach😂 mine certainly doesnt
In video form,it's way easier to teach.Including animations for visual aid.
But true,he seems advanced at Science.
i know right I dont really understand it when my teacher explains but when I look at these videos a lightbulb goes off😂
it helps if you can rewind...
This 13 minute video summed up my 50 minute long Bio Process class about a 3 weeks ago.....Gotta love the internet.
Hank Green is my favorite crash course teacher. Thank you for helping me become more confident in my psychology and science courses for nursing school. I'm a huge fan! You're the best, Mr. Green.
I used to watch these videos all the time in high school and they got me through AP bio my sophomore year... I took a few years off after high school (so its been a while), and now that I'm in university majoring in biology, crash course is once again saving my life - thank you!!
This is probably the most complex topic in Cell Biology. It's a little difficult to keep track of what's being broken down, what and how much is produced and most of all, how is it all produced. Thanks for the visuals and keeping this topic entertaining.
Jazzerlat45 It really does help if you just write out the whole mechanism. It really helps you understand what's going on and what's produced (and the names of the enzymes and products being created). I think oversimplifying such a complex process like this does more harm than good: it just leads to confusion. It really makes a lot of sense if you just draw the whole thing out, step by step, molecule by molecule.
Who else is cramming for a college bio exam?
iam studying for my ap bio class as a freshman in highschool
i legit have an on line exam right now and a essay to right on this
Grade 11 Bio
😭
Its currently 4:29 am, my test is at 11:00 and lets just say I was doing extra credit for another exam I have later today that now im finally studying for this exam and I fear it might be too late, please pray for me.😅😴
my brain is not excepting this knowledge
ilakrnb your brain is not expecting the fact excepting is spelled accepting
Break it down into small steps, one step at a time buddy. Review it several times. One step at a time! When you understand part 1, go to part 2. Never give up.
@@MRWOOHOO1313 wooosh
ilakrnb is that DEAN
@@cosmiccosmog3919 I don't think that's how the wooosh joke works. Michael is not ignoring the joke, he's just correcting ilakrnb's spelling.
Having a panic attack from my bio course breezing through this and moving on in 45 min.
With attention and learning issues, I must work 6x as hard to understand simple concepts.
Your program has really helped me and others like myself to stay afloat.
Thank you sooo very much!!
the biology community has the funniest students and this comment section is proof
moayad al lahamm We’re also the most miserable
IM ONLY A HIGH SCHOOL FRESHMAN!! WHY DO THINGS HAVE TO BE SO COMPLICATED!!
Same I have a quiz tm! And my teacher sucks so I have learned nothing and we’re already in second quarter!!
same here ikr
Mood
its wild cause if you choose to attend college you'll be faced with these same concepts again lol its crazy how you're probably 14-15 learning the concepts im relearning as a 19 year old lol
when u learn more watching crash course vids than paying attention in class
Despite all of the hate left on your comment log, I thought this was a very educational and entertaining explanation of respiration. The visual displays were awesome, The sound effects kept me amused and the fun facts were note worthy. I hope to see many more videos from Hank and Crash Course
Dante Sprull I WAS THINKING THE SAME THING! so much hate out there. This is made to coincide with your education, not replace it.
On behalf of every IB Biology student around the world, I just wanna say thank you 🙏
thank you hank green, you don't know how many lives you have saved
Asia Chan well he really saved mine
good luck to all of you that are going to sit for Biology exam :D god bless
thanks. appreciated
Bio exam is tomorrow, and thanks ^_^
Wenndey Luvette mines tomorrow!😭 good luck to others too
Lash Clash i passed with flying colors 😘
you're pretty, marry me
My biology exam is tomorrow and I know everything now because of this video. I have this weird way of memorising things that interest me or its so visual that it stays in my mind. That is why I'm sure I will do well tomorrow. Great video! Crashcourse is the best way to study! Thanks a lot
* *Le jealousy* *
Thanks for this great video!
Some other helpful things to note that were not explicitly stated in the video:
-The Krebs Cycle occurs in the inside of the inner mitochondrial membrane AKA in the mitochondrial matrix.
-Another name for the Krebs Cycle/Citric Acid Cycle is the Tricarboxylic Acid (TCA) Cycle, so if you ever hear those terms, know that they all refer to the same process.
-Cellular respiration occurs not only in animal cells but also in plant cells.
I still love you asapscience, but, I've found someone else... what we had together was special, in Grade 9 i nearly learnt the periodic table because of you! but crash course, well he makes me feel so smart, so ready for any quiz. I would always love you, and cherish the time we had together and maybe one day we'll get back together... I'm still going to spend time with you but I think we should see other people. I'll always love you asapscience.
This kind of made me sad .. And reminded me of other emotions
+tatiana jacques Awww, it was just a Biology reference. No need for feelings in science!
Lol, ASAPscience will always be my first love too XD What grade are you in now? I'm in 12th
Can we switch brains for my test?😫
Not possible, I thought ur learning bio. U should know
@@msjsss1102 lmao
@@msjsss1102 if u take out your brain, will u die?
@@jamarimcfarlane4844 yes, very dead
@@msjsss1102 lmaoooo
That's how you teach biology. I hate the biology teachers at my school they just read out the text books. You rock!!
love
Everyone's saying "My exam's tomorrow" and I'm like "My exam starts in an hour" ;-;
guys please pray for me to pass the test. I dont want to dissappoint my parent. wish me luck
good luck :)
I'm screaming. Mark is my ultimate bias lmao
Dont worry you'll pass good luck
don't worry, you can always make your other parent proud
and how did it go?
You've explained this better in 13 minutes than my bio professor did in 3 hours. This is going to help me with my exam in the morning.
Hank talking abt the cellular respiration in 13 mins. made me understand WAY BETTER than my teacher's lecture for 50 freaking minutes
For those who are wondering, a phosphoglucoisomerase is an enzyme that catalyzes the conversion of glucose-6-phosphate into fructose 6-phosphate in the second step of glycolysis.
I wish they had like on line test after every episode to help you understand it even more
Well there's always past papers + mark schemes. Going through papers is great revision I think :)
HANK MY PROFESSOR LINKED THIS AS A GOOD RESOURCE I AM SO HAPPY RIGHT NOW
Yeah my teacher did too! I was so excited, I've been using it for bio all year and I'm just glad that he sees it as a good resource as well. I hear too often about the evils of the internet, particularly TH-cam, killing the brains of our generation.
Mine did too! She actually posts links to these almost every week! I've been watching for a while, but now all my Nerdfighter high school friends freak out. ^^
yes.. i've learned so much.. i better link this to my teacher.. :D
Can I just add something that confused me for a while and only recently understood it. Glucose does not "produce" 32 ATP molecules. It provides the hydrogen ions to create a potential difference between the membrane which can then be used to synthesise ADP into ATP. The molecules of the ADP, ATP, and the phosphate group that breaks off/attaches on to ATP/ADP circulate around the whole system, again, they aren't "produced" by glucose alone.
I was struggling over this concept for over a month before I had a deeper look into this, and thought this might benefit another person who came to this video looking for help.
Alexander Wung Actually, Glucose provides the electrons required for the ETC to create the proton gradient.
+Alexander Wung i have a friend called alexander wong
+Alexander Wung You can think of it as a power plant (brace for some long physics and more chemistry). Lets take a coal plant (ignore the environment for now or lets just say that proper measures have been placed to make sure the environment gets left alone)
The glucose is the raw material in the reaction like coal. Its molecules contain all the energy in the form of chemical energy. During glycolysis, energy is needed to break the bonds in the glucose molecule (like activation energy). This is why we need the initial supply of ATP, to provide the activation energy. This is like heating the coal up in order for them to burn. Once the bonds are broken, the formation of new bonds releases more energy such as the formation of pyruvate molecules and 4 ATP molecules in glycolysis.
Next, the energy that remains in the pyruvate molecules is extracted. In the Kalvin cycle the energy remaining in the pyruvate is extracted but is not directly stored in the form of chemical energy in ATP yet. It is instead stored in the form of chemical energy the molecules NADH and FADH2. Back in the power plant, this is like the coals burning and releasing energy into the water around them. The energy that was stored in the coal is not converted into electricity directly, but converted into heat energy in the water, which is then utilized to get the electrical energy.
Finally, we get to the electron transport chain. The energy of the NADH and FADH2 is converted into potential energy in the proton gradient (hydrogen ions concentration gradient). This new form of energy is then used to synthesize ATP as the protons flow down their gradient and activate ATP synthesase. Back in the coal plant, the heat energy is used to turn the turbine blade, the heat energy is converted into kinetic energy. the turning blade then produces energy.
quit simply, glucose doesnt form ATP, but the energy stored in glucose is transferred to ATP through cellular respiration. Energy is flowing from glucose to other molecules and finally ATP.
+Alexander Wung Correct me if I'm wrong, but in glycolysis and krebs cycle, molecules derived from glucose ie. pyruvates and acetyl coA are used to make ATP. So glucose makes some ATPs while the rest are made from the potential difference. Also I'm pretty sure that anaerobic bacteria get most of their ATP from glycolysis in which glucose is broken up to directly produce ATP.
"CHINESE YEN". :-D
-Well he teaches bio
I am in A&P and found your video the only way I was able to understand this concept. Helped me tremendously for my comprehension of the subject. THANK YOU SO MUCH for making this!
Thank you for existing!!! I'm in a fast paced nursing school (as in my general studies like anatomy are very very fast paced and I can't get below an 85 in ANY of my classes or I FAIL) and we're going soooo fast I got super lost last week. (we did everything about the cell including mitosis and meiosis in less than 2 hours!) ugh. My professor even admitted it was an 8 hour class. I haven't seen this stuff since 7thh grade since I skipped high school biology. Brilliant choice. Anyways, rambling. Carry on!! Thank you!!!!!
Lol how was it inappropriate? But thanks!
Night before finals, eating cookies and drinking hot chocolate, for a last minute review! This is the college life.
Same lol
+Zachary Goodrode But this is a high school level lesson?
+So Hysterical Not necessarily. It's got some college level bits. Not doctorate level, but it served its purpose teamed with other vids.
Cheers.
Hmm.. You learn something new everyday haha
that sounds amazing!!
It's crazy I keep coming back to this video: for GCSE biology, for A level Biology, for first year of uni and here I am again for a cell biology exam in third and final year of uni. V thankful to this video tbh. Impossible to long term remember respiration - too complicated lmao
Bio final tomorrow...pray for me please.
I wish you all the best!
My finals aren't until after break, which is terribly challenging after vacationing for a month.
I got a 96 on my honors bio final. Yay!!!!! Good luck on all your finals everyone.
+T Grey Same here. Omg
Haha twins! :)
if you're watching this,
it's too late.
Allan Ochoa i still dont understand shit after watching it...
ask me questions, I took a test on this and aced it btw,
Allan Ochoa I know but let me be in denial D:
I know. I have an AP Bio exam in 2 weeks so I need to get this crap down but even after watching Crash Course which I usually understand, I still feel like I'm at square one :/
We're all so fucked :(
Who's cramming for the AP bio exam Monday!!!!!
I HAVE HAD 4 CLASSES TRY TO EXPLAIN TO ME WHAT YOU DID IN LESS THAN 15 MINS. this is why I watch crash course, the moment you said money my brain started to work THANK YOU
great studying is being done with this for bio midterms. THANKS
Your show is absolutely amazing, thank you for being the only reason that I will pass my test tomorrow. Actually Gods a reason too.
Amen lol
The fact you had a test is proof there is no god
Jks
Moe Sun did
The irony of this comment lol
WTF! Comment section has turned into Prayer request section.
Solomon Angom I See 😂😂😂
same
no kidding 😂😂😂 the topic needs god loooool
lmao
😂😂😂😂😭
BEST WAY TO EXPLAIN A COMPLICATED PROCESS. MOST VIDEOS DON'T ACHIEVE THE GOAL. CONGRATULATIONS "CRASH COURSE"!!! Graphics, Pauses, descriptions..excellent!!
I'm stressing out so much, I'm in biology right now and I'm afraid I'm not going to pass:( All of this is very confusing to me
Kristen same 😢
even tho i don't, but u might be because he didnt explain glycolysis, prep phase, krebs cycle and etc in detailed. there is a lot more steps in each of these(like 10). u should look up detailed explanation of these processes and then it might make more sense. good luck;)
Z Grace i know today I was looking through a PowerPoint he provided for us and I got mostly everything. The only thing that's really bothering me is the Krebs cycle.
I remembered I had recorded my professors lecture and relistened, and I get it now!
Jorge Olivares agreed i just had a quiz on glycolysis prep phase and krebs cycle and krebs cycle is the hardest to remember in my opinion bc of all the names.....
Me: watches video night before test in hopes of understanding
Also me: wtf is he even saying
(No offense to your video I'm just an idiot)
HellNaw ToTheNawNawNaw me
HellNaw ToTheNawNawNaw I have a bio exam in less than 12 hours
FanGirl ASMRandMORE literally me
Y Man and 1girl group sex hd movie Jacky sheriff court on on the
Better than me I have my test in two hours and am scrambling to figure this out...
Just saying, I'm pretty sure the Krebs Cycle occurs in the mitochondrial matrix, and not the inner membrane. I am currently in honors bio, and my teacher made it clear that glycolysis occurs in the cytoplasm, Krebs cycle occurs in the mitochondrial matrix, and oxidative phosphorylation (ETC) occurs in the inner membrane of the mitochondria.
Yeah I was kinda confused by that as well. You're right, my teacher also stressed that the Krebs Cycle did its thing in the matrix.
Stubbs Chua same I heard that too from my teacher and we have a test on this along with other topics. ug honors bio....fml
Yep, taking AP Bio right now and every source I've checked say the Krebs cycle occurs in the mitochondrial matrix. So I think you were right!
Krebs Cycle does occur in the mitochondrial matrix HOWEVER one of its key enzymes known as "Succinate Dehydrogenase" is actually membrane bound... and it's bound to the inner mitochondrial membrane.
I got a notification for this.... while I was sleeping..... and you woke me up.... FOR THIS
Im a college student and watching this like 10 mins before my midterm 😅😅
you,my friend,are an O.G
SAMEE
I’m watching this before my final
I am never going to think about biology again after this
do you want a medal?
hope you did well
Procrastination at its finest lol
This video made me realise I need to learn chemistry.
LOL i said the same i think ill start with crash course chemistry
This video is too simplified for my test 😭the intermediate names are pure cancer
DEADASS
quick salute for this man who is single-handedly getting me through AP Bio *heart eyes*
My exam is tomorrow. Wish me luck!
How did you do?
142/150 = A :)
Good job! ^_^
yeah. I had to watch some parts over and over to get it though
You should watch bozeman science instead
It's 2020 and my "Science for Teachers" instructor assigned this video and I am a happy nerdfighter for that! Will continue to use these videos in my class as a student and I'll use crash course kids when I have my own classroom one day! :D
Who needs to go to lectures when I have a book and this?
Samantha Yarnell lol exactly
?
Miguel B yo can u not
+Macky Schmit Are you going to sit and there and do nothing or are you going to put him in his place??
+Miguel B u r a pervert
hey guys, i really found this video extremely helpful. I want to ask if it possible that you do a more in detail video of the ATP production of the different cycles separately? I think separating the cycles will be really helpful and easier if you struggle with only one cycle. Your videos have literally helped me pass so many exams and even do well. Thank you so much.
Wish me luck on my test (tuesday). I'm gonna need it!!!
+The Legendary Luxray how did it go?
muffinchini 96%, the highest grade in my class!!!!!!
+The Legendary Luxray AWESOOME
Grace Baker Thanksssss
WELCOME
CRAMMING THE NIGHT BEFORE MY BIO EXAM, WHO'S WITH ME?!?!
I am Right now!!!!!
Gang
All I do to prepare for bio tests and now this exam is rewatch all of Hank's videos and make notes on them.
Raise your hand if you're cramming for an AP test!
Rachel K.
CLEP.
Sat subject test 😩
Aisha Diallo me too 😭
Rachel K. Me
🙋🏻♀️🙋🏻♀️ meeeee
Actually it's *Japanese Yen not Chinese. China uses RMB
+moon bunniee LoL
+moon bunniee I think he's thinking of Chinese yuan and just mispronouncing it slightly by not making the 'oo' sound.
Team Hank!!
...Ahem
+moon bunniee Lmao, he really does say "Chinese Yen", honest to god.
+moon bunniee stop trying to protect him guys. Just accept that he made a mistake and that's fine. I live in japan and it's definitely JAPANESE YEN.
+Jasmin Castilla i dont care
this 13 minute video explained way more than my teacher can manage to in 3 weeks
What youtube videos does this guy watch to get ready for HIS presentations?
You are the only reason I'm passing biology. Bless ur heart
If this video gets me an A on my bio quiz tomorrow, I'll like and subscribe.
Did it?
+Adidas AMM Why the coercion?
Omg same
I'm on the edge of my seat. How did you do?
Thank you so much Hank, this video has literally everything I need to know about respiration for my A-level Biology topic test!!
couldnt agree more !!! thanks a bunch hank-o
Btw Yen is Japanese currency and Yuan is chinese currency
So everyone is here because we all just reached respiration and photosynthesis in our bio class, right?
and finals
Christopher Arroyo Nah I'm here for fun.
yup
I'm a physics major, just here for kicks.
yep
Who the fuck dislikes this video? It's both interesting and educational.
Why even worry? You benefited from it, but not everyone has to.
I would say some creationists, but I'm being too bias there.
vverewolfchick Not everyone hates it, just people who don't like learning.
or people who'd rather watch real lecture instead of wasting time going completely off the topic by some weirdo :)
lmTheDudeMan Well this video isn't a Lecture but more of a review and crash course on the topic. If this was a lecture, it'd be typically 30 minutes to an hour long for obvious reasons.
Im reading all these comments about ap bio and im literally a freshman and im learning this wth its too complicated
+casey lydon I'm also a freshman in high school and I had a C but I have an F so Rip
lol same I have 1st semester benchmarks and finals for bio this week
I’m cramming rn. I HATE BIO it makes no sense. And I have finals next week
thats why you should go down to advanced and not pre AP
@@adolfocepeda6633 It's no pre AP it's mandatory for all freshmen, at least in my school
00:00 Cellular respiration is how we derive energy from glucose.
01:37 ATP is the currency of biological energy
03:16 ATP is minted through cellular respiration
04:44 Glycolysis generates 2 ATPs and 2 NADH
06:30 Anaerobic respiration leads to lactic acid build-up in muscles
08:13 Enzymes in the Krebs Cycle create ATP and CO2 through a complex cycle.
10:09 B vitamins Niacin and Riboflavin hold high energy electrons for later use in the Electron Transport Chain
11:44 Animal cells make ATP through cellular respiration
The mitochondria is the powerhouse of the cell
And this is why I did physics: because biology is ludicrously hard and complicated
This is more in the area of chemistry than anything.
+The Great Danku Tree biochemistry
+The Great Danku Tree Celular biology obviously has chemestry in it.
+The Great Danku Tree This is actually studied by biology, not chemistry.
We are talking about cell respiration .. I hope that rings a bell.
you have a pretty dank name
Omg I love this guy. So much more helpful that textbooks who overcomplicate things
you are sooooo right!!!!!!!!!!!!!!!!!!!
hi! I loved the video but I want to clarify that when we feel that our muscles are hurting it is not for the lactic acid, it's because you destroy some cells and muscles doing exercise so it's like having a bruise in your muscles. They are not used to doing a lot of work
Have an a level exam in three days and cramming in 👌🏽👌🏽👌🏽👌🏽👌🏽
Didnt need to know that
He is the reason i understand Campbell biology chapter 9
I'm a chemistry and biology teacher and I love your videos, but I have one qualm: Energy is released when bonds are made, not when bonds are broken. It actually takes energy to break bonds, which is often portrayed incorrectly when it comes to biology and ATP. I don't have a quick fix for this, because it seems that explaining the truth of how ATP is used as "energy currency" in cells gets very complicated when you add this wrinkle. Still, just sayin, this video may be reinforcing a popular misconception.
Thanks for all the videos, I really do love them.
isn't it because the breaking of ATP is an exergonic reaction, with a low activation energy, therefore releasing more energy than it takes to cause the reaction? i thought that was the explanation, I don't mean to be critical
No, you're fine Sam. There's a good chance that I'm confused about this topic, and I'm making sense of it still since having my mind blown about a year ago. I'm under the impression that breaking bonds ALWAYS requires an input of energy, and forming bonds ALWAYS releases energy. When atoms are attracted to each other to make bonds, the bonding is accompanied by a release of chemical potential energy.
From what I understand, ATP is a useful molecule because, like you said, breaking the 3rd phosphate bond has a very low activation energy, but in any case breaking that bond requires an input of energy. What I'm saying is that the actual energy release that happens after, the exergonic portion of the reaction, must be a result of a later bonding event. If all of the above is true, then saying that breaking a bond in ATP releases energy is promoting an inaccurate idea by ignoring the fact that CREATING bonds releases energy.
Happy to be corrected if I'm wrong.
Bill Weisberger I think it's because there is free energy released in the conversion of ATP to ADP, as the enthalpy of ATP is higher than ADP. Yes, there needs to be an input of energy in the transition state, but the free energy change makes the overall reaction exergonic. At least, that's what I've understood from two biochem lectures in med school haha!
Even after 11 years, this video is still used by a student who is cramming the night before… it’s me. I’m the student
Crash Course:
The best place to go to when you haven't studied for months
Using this to study for my bio exam!! I've failed every other test in that class, so I'll update on this one :)
bro how did it go
I feel ya bio is my worst class lol
Fun fact about ATP, if you were to take every molecule of ATP in your body you would have enough to fill up about a shotglass. It's amazing how this stuff works.
I want to take a shot of that :) like every time before the start of a race :DD
This kid is so smart and so helpful. Thank you yung blood. You just helped black man get his degree. Go to bed tonight knowing that you impact lots out us out here. Thank you.