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Nick Jenkins of Crash Course faces off against Hank Green of SciShow in this collision of science and nerdy pop-culture references.

Hosted by: Michael Aranda
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Roman Concrete

Lycurgus Cup





Midichlorians Bacteria

 (00:00) to (02:00)


Michael: Hello and welcome to SciShow Quiz Show, where two smart people battle each other in science trivia for pride and glory, but mostly for fun.  We're all friends here.  

Hank: Uh, yes, accurate. 

Nick: For the moment.

M: For the moment.

H: Oh, wow.  

M: I'm your host, Michael Aranda, and today our contestants are Hank Green, a fan of the very talented local celebrity Abby the corgi.

H: I am a fan of Abby.  

M: And he's competing against Abby the Corgi's human, Nick Jenkins.

N: That is correct.  

M: Nick is also the producer and director of the Missoula Crash Course series and the editor for Dear Hank and John.

H: Yeah.  You might hear that name, Nick Jenkins, if you listen to Dear Hank and John.

N: Mostly, you just hear John saying 'back up, Nick'.

H: 'Back up.  Back up'.  That's what you hear.

N: Yeah.  No, that's true.  Unless you're at a liveshow.  

H: No one else hears 'back up, Nick'.  Oh, yes, even then, we ask Nick to back it up, because boy do we wish we hadn't gone there.  

M: As a special thank you to our supporters on Patreon, we've randomly selected two of you to win some prizes.  Hank, you're playing for Reggie Smith.

H: Hello, Reggie.

M: Nick, you're playing for Gary Moon.

N: Gary, I'm sorry.

H: Hey, I lose all the time.

N: I'll do the best I can.

H: I lose so much.  I feel like more than half the time these days.

N: I'm here to make you feel good about yourself, just today.

H: I've been anchored.  I've been weighed down by the weight of--

M: Fatherhood?  Stefan, show our contestants what they can go home with today!

Stefan: Reggie and Gary are up to potentially receive some prizes today, depending on how their respective contestants do.  There will be some signed cards from the final round, but nobody really cares about those.  What you're really here for is the pins.  Yes, there will be an 'I Won SciShow Quiz Show' pin and it will be given to the person who wins the show, but will they really have won the show, because the other person will receive the 'I Lost SciShow Quiz Show' pin and they'll feel so warm and fuzzy inside, they won't know what to do with themselves.  But who will it be?  We'll just have to wait and see.

M: Okay, both of you start off with 1,000 SciShow bucks.  

 (02:00) to (04:00)

Each time you answer a question correctly, you'll win 200 SciShow bucks.  If you answer a question incorrectly, you'll lose 100 SciShow bucks.  

N: Okay.

H: Okay.

M: Are you guys ready?

H: Yes.

N: Yeah.

M: Okay.  Question one is about old Roman technology.  Your specialty.  

H: Hey, Nick, it should be called SciShow Guess Show.  Let's be honest.  

M: Specifically, we're talking about stuff that seems way too advanced for its time.

N: Okay.

M: So modern concrete is made of chunky material like sand held together by paste-y cement and modern cement is calcium oxide, also known as lime, plus other compounds.  Engineers today make structures out of different kinds of concrete, from bridges to building foundations, but under tough conditions, modern concrete can crumble within a few decades.  Scientists have discovered that a type of concrete used in Roman piers, 2000 years ago, is stronger today because of a chemical reaction that's changing the cement.  So what's been reacting with Roman concrete to make it stronger: seagull poop?

H: Oh, that'd be awesome.

M: Sea water, a secretion made by barnacles, or acid rain?  Your face.

H: What?  What?

N: I'm gonan go--I'm gonna go with the barnacles.

H: Barnacles do secrete very strong glue.

M: Unfortunately, that is incorrect.

N: Dang it.

H: I'm just gonna say sea water.

M: That is correct.  

N: That goes against everything I have ever learned about salt water.

H: Yeah.  Yeah.  It takes everything apart, except apparently Roman concrete.

N: Apparently.  Sorry, Gary.

H: I think I'd heard that, but also it seemed like the safe choice.

N: It did, which is why I didn't go with it.

H: Yeah, so, but seagull poop would have been so good!  I wish I lived in that world.

N: Do you know how much seagull poop though?  That would be a lot of seagull poop.

H: Well, I mean, have you--it's thousands of years of seagull poop.

N: I still, yeah.  Alright, fine.

Olivia: The answer is B, sea water.  With hints from old records, we think that Roman concrete was made of volcanic rock chunks held together by lime, also known as calcium oxide, along with sea water and volcanic ash, which could have been a lot of different compounds, including silicone containing ones.

 (04:00) to (06:00)

Modern cement tends to start cracking if the components react with anything to form new chemicals, but scientists think that Roman concrete actually grows stronger as sea water dissolves part of the volcanic ash and lets new minerals form, especially out of calcium and silicon atoms.  In the mid-2000s and in a 2017 study, a team of researchers found a couple of rare minerals, including aluminous tobermorite and phillipsite that are likely made from these reactions.  Because their crystal structures are really sturdy, these minerals reinforce the concrete and help it resist cracking, but even with this knowledge, the exact recipe and steps to make Roman concrete is lost, so we won't be using it in our piers anytime soon.

M: The next question in this round is also kind of about liquids.  Specifically, it's about a 1600 year old liquid holder.

H: Okay, good.  We've got it.  We linked it together perfectly.

N: It's all coming together.  We got it.

M: It's called the lycurgus cup.  

N: Okay.

H: Probably.

M: The designs on it depict a story from a myth which is how it got its name, but the cool part is, when it's lit from different angles, the glass of the cup can look pale green or a completely different reddish pink.  It's kind of like a magic trick and it's stumped museum curators and researchers for a little while, but we've figured out the secret.  

H: Interesting.

M: What causes the color change: the film of old wine molecules inside the cup, wine molecules in the pores of the glass, a synthetic pigment in the glass, or metal nanoparticles in the glass?  

H: You got--I'll go--I can go first 'cause you went first last time.  I'll gonna--I'm gonna go with, I'm gonna go with metal nanoparticles.  That's gotta be wrong.

M: That's correct.

H: It's right, oh my God.

N: That was the one that I was definitely not gonna guess anyway, so.  

 (06:00) to (08:00)

H: Then I saved you.  Metal nanoparticles, I say confidently, as if I am sure that this is the actual answer.  

O: The answer is D, metal nanoparticles in the glass.  If light is shined on the lycurgus cup so it reflects off the glass and into your eyes, the glass appears to be a pale green, but if light is shined through the glass and gets transmitted by it, the glass appears to be a glowy reddish pink.   This dual coloration where the light is reflected or transmitted by an object is called dichroism.  Thanks to studies done between 1960 and 2007, we know this cup is dichroic because of silver and gold nanoparticles that were mixed into the molten glass under the right conditions to form tiny metal alloys.  When light hits these alloys in different ways, their electrons change the wavelengths of light that makes it into our eyes, and that's what makes the glass appear reddish or greenish under different conditions. 

M: Okay, this next round is called 'Guess what this gene does!' and it's a slightly different format.  Four rapid fire questions which each have two choices each.  

H: Okay.

M: One general way that scientists name genes is by figuring out what they do, like what proteins they code for and what goes wrong when they don't work normally, like how (?~7:09) mutations, sometimes spelled b-r-c-a 1, are related to breast cancer.  It's a tumor suppressor gene in humans, and sometimes, scientists decide to describe how a gene works based on references to TV shows, books, or movies, so let's start out with one--

N: So we have no real system.

H: No, absolutely no, no, no.

N: What would be fun today?

H: Yeah.

N: Probably would, yeah.

H: What I feel like.

N: Yeah.

M: So we're gonna start out with one for Star Trek nerds.  What happens when the fruit fly gene called 'tribbles' isn't working: flies are born pregnant with cloned babies that give birth right away or fly cells divide too quickly?  

H: Fly cells divide too quickly because that would be way easier than the other thing.

M: That is correct.

N: That is, because that is what tribbles do.  

M: Okay.

O: The answer is B, tribbles is involved in cell division.  Any living thing's development depends on careful timing of the replication and growth of cells.

 (08:00) to (10:00)

You need enough cells to form different body parts and sometimes you need a little extra time so that those cells can do things like move, attach to each other, and develop specialized functions.  The cell cycle is a multi-step process that cells go through when they replicate and divide, and the gene tribbles helps regulate the timing of the cell cycle.  Specifically, tribbles encodes proteins that interact with other enzymes to block the division step of the cell cycle, called mitosis.  This pause gives cells time to do other things, like change shape.  So when tribbles isn't working normally, cell division can happen too much in developing flies, which causes some pretty bad problems and it reminded researchers of how tribbles in Star Trek divide uncontrollably.  Go figure.

M: The second question's related to The Wizard of Oz.

N: Oh crap.

M: In fruit flies, what happens when the gene tinman isn't working: flies are paralyzed when they touch water--

N: The second one.

M: --flies don't develop a heart?  That is right.  

H: Yeah, it was right, the second one was correct.  

N: I knew it wasn't the first one.  

H: That's good.  That's good, good policy.  

N: I got one, Gary.  

H: Oh man, so, I didn't know flies had hearts.  

M: Well, everyone has a heart.  

H: But they don't have a circulatory system, do they?  

O: The answer is B.  Tinman is involved in heart development.  Tinman is what's known as a homeobox gene, which is a kind of gene that gets expressed in very early development and helps guide cells to form very specific body parts, like different organs, and tinman is involved in the development of a few parts that have muscle tissues, including the heart, which is where the name comes from.  The tinman in The Wizard of Oz needs a heart.  Researchers have studied flies that don't have a working tinman gene and noticed that they don't form cells called cardioblasts, which eventually divide and develop into heart cells.  So basically, something encoded by the tinman gene normally binds to other regions of the fly DNA to help say, hey, these cells should become heart and muscle eventually.

 (10:00) to (12:00)

But, when it's not working, the protein isn't produced and the chain reactions aren't started that help the cells develop properly.

M: Third question in this round is based on another film and literary classic.  In zebrafish, what happens when the gene dracula isn't working?  In light, the red blood cells of zebrafish burst or the zebrafish need extra zebrafish blood in their tanks to survive?  

H: They need--

N: I'm going with B.

M: Incorrect, I'm afraid.

N: Who knew?

O: The answer is A, dracula is involved in how blood cells work.  When the gene dracula isn't working in zebrafish, they basically have a genetic disorder where exposure to light makes their red blood cells burst open, which biologists call cell lysis, which is kind of like how some fictional vampires burst into flames in sunlight, and researchers think it's because dracula encodes an enzyme that helps wrap up the final steps to making heme, the iron-containing molecule in the protein hemoglobin that lets your red blood cells carry oxygen.  If heme isn't being made, one of the ingredients called protoporphyrin IX builds up because it's not being used and this molecule probably interacts with light to produce some red blood cell destroying byproducts.

M: Now the last question for this mini-round is a Tolkien reference because we had to work one of those in.

H: Okay.

N: Sure.  

M: So in fruit flies, what does the protein encoded by the gene smaug do?  

N: You got 'Smaug' right.

H: Yeah, good.  That was good.  Well done.  Smaug.  

N: Yeah, good job.  

H: I would have said 'smog'.  

N: Yeah.  Most people do.

M: Does it bind to the protein encoded by the gene thesauros, which means treasure in Greek, or does it inhibit the expression of a gene called nanos, which means dwarf in Greek?  

H: It inhibits a dwarf or it binds to a treasure.  I love scientists.  I'm going to go with it binds to thesauros.  

M: That is incorrect.


O: To understand smaug, we have to understand nanos.  

 (12:00) to (14:00)

And nanos is another developmental gene, which helps with the formation of sperm and egg cells along with things like normal abdomen development.  Now, to make proteins, the DNA in genes is first transcribed into messenger RNA, another kind of genetic information storage, and then translated to assemble a protein, and the protein encoded by smaug specifically messes with that translation step.  Interacting with molecules and the nanos mRNA.  This suppression of nanos actually helps with normal abdomen organization.  A lot of early development is based on things like gradients of proteins that help tell cells what to become, so when smaug isn't working, development tends to go wrong.  Even though Middle Earth didn't really benefit from Smaug the Dragon taking over the Lonely Mountain from the dwarves, but you know, it's fun.

M: Okay, we're on to our final round, and I'm going to tell you before you place your bets that this is related to nerdy scientific names, so you can bet any or all of your points on the answer to the next question.  Okay, Hank, you've got 1500 points.  Nick, you've got 1000 points.  Place your bets.  We'll go to commercial break.  

Welcome back, probably.  So whole species can be named after pop culture icons, too, mostly because the researchers noticed that something looks like Lady Gaga's costume or Batman's cowl or the Sorting Hat from Harry Potter.  There are literally hundreds of these, but occasionally, scientists name species after something fictional because they behave in a strange or similar way, and that seems to be the case with a bacterium that infects ticks that researchers named midichloria mitochondrii.  

H: No.

M: Named, of course, after the midichlorians in Star Wars.

N: But only in the prequels.

H: To be clear.

N: Yes.  

M: You may know that those were the microscopic symbiotes that were introduced in the prequels.

H: I may know this.

N: Yeah, I know that.  I know that.  

M: Nick doesn't wanna know that, but he knows that.

H: Let's explain the Force.  That's what the world needs.  To explain the Force.  

 (14:00) to (16:00)

It's called the Force.  

M: So if you had enough of those in your body in Star Wars, you could detect the Force.  So why do you think the researcher picked that name for this bacterium: the bacterium lives inside mitochondria, an energy-making organelle of infected cells, the bacterium replaces the mitochondria of infected cells, the bacterium allows ticks to detect weak electric fields, or the bacterium allows ticks to produce weak electric fields?  

H: That's cool.  Any of those are very cool.

N: Any of those are very cool.

H: Yeah.

N: And weird.  

H: Yeah.  I would, I'm gonna go with--is there--is there a F, because none of those seem particularly likely.

M: Are you guys ready?  

H: No!

N: I'm ready.

H: I have written nothing down.

M: Nick's ready.  

H: Okay.  Uhh.

N: I was like, what's weird, but somewhat plausible?

H: Yeah.  I--well.  Hm.  I'm having a really hard time.  

N: I've already made my guess, so you can think it out if you need to, you know, it's--

H: A was infect the  mitochondria, B was replace the mitochondria--

M: Yes.  

N: Gonna get it wrong, gonna get it wrong.

H: Okay, I wrote something down.

M: Okay.  Show your answers.  So, uh, unfortunately, you're both incorrect.  

H: Oh, that does not surprise me that much.  

M: So, I think that means Hank wins.

N: Hank wins.  

M: By 250 points.

N: Yes.  

H: -ish.

M: -ish.  

H: 'Cause I bet 500.1.  

N: Oh, good lord.  

H: Hey, alright, what's the answer?

M: The answer is A.  

H: Oh, interesting.

M: The bacterium lives inside mitochondria of infected cells.

H: Okay.  That's more--that's more likely but less cool.

N: And less like midichlorians.

H: Yeah, a little less like midichlorians.

N: Yeah.

O: The answer is A.  The bacterium lives inside the mitochondria of infected cells.  A team of researchers was studying a tick species that's known for carrying lyme disease when they discovered a new bacterium hiding out in the tick's ovaries and upon closer look, they found that the bacteria weren't hanging out in the cytoplasm of cells like bacteria normally do.

 (16:00) to (17:39)

Instead, they were inside some of the mitochondria, the machinery inside cells that produces energy.  They somehow picked some of the mitochondria, maybe the older ones, the researchers suggest, get inside, and eat them up.  This is the only bacteria species we know of that infects mitochondria like this and when this researcher was sent ticks from all over the world to study, he found them in every single set of ovaries.  This was a really weird and big discovery, so the researcher wasn't sure what to call this species.  In 2006, when he published the official species description, he e-mailed George Lucas for permission to use the idea of midichlorians.  Presumably, he came up with this because these bacteria are hiding out in the cells of a whole bunch, if not all, ticks.  Cells within organelles within cells, and I guess we could all use another Star Wars reference in real life science.

M: Well, uh, congratulations, Hank.

N: Sorry, Gary.

H: Reggie, thank you for being a Patron and I'm glad that we get to send you stuff.  

M: Thank you for watching this SciShow Quiz Show.  If you want to see more of what both Hank and Nick work on together, you can go to and of course, if you want to help us keep making videos like this, you can go to