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BISC 2083 - 9/28/26 (Ch 5/6) — Transcript

by Juliana Kemege · 8,674 words · 1,327 segments · language en · Watch on YouTube

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0:00When we talked about viruses last time,
0:02we talked about um how viruses only grow
0:07within a host organism, right? And we
0:10spent a whole chapter talking about how
0:12we grow bacteria when we're testing for
0:15bacterial infections, how we grow them
0:17in a lab. And bacteria, you put them on
0:20media, right? You the five eyes, right?
0:23You inoculate them, you incubate them,
0:25blah blah blah blah blah blah. Now the
0:27difference between bacteria and viruses
0:30or a big difference is that bacteria
0:33grow really really easily in most
0:35environments. If we took an augur plate,
0:38even not even an augur plate, if we took
0:40um a bowl of ice cream and left it out
0:44at room temp for 24 hours, you'd have a
0:47bacterial culture. There'd be bacteria
0:49growing in there. Most of you probably
0:51have bacteria growing on your shower
0:52curtain, probably in your toilet, right?
0:55There's bacteria everywhere. They're e
0:57really easy to grow for the most part.
0:59Um it's not a difficult process. Most of
1:03you are going to be growing lots and
1:04lots of bacteria in lab. You know that
1:07it doesn't take very much. Okay. Viruses
1:10are quite a bit different because
1:12viruses again are only going to grow if
1:15they are inside of another organism. So
1:18the tricky thing about viral cultivation
1:21or growing viruses, cultivation is just
1:25a fancy word for growing.
1:28When you're growing viruses is they need
1:31a very very specific type of environment
1:34to grow. They're very difficult to grow
1:37because they require a live host cell to
1:41grow.
1:43They cannot be cultured in regular
1:45media. There's no type of just
1:49um for the most part there's no type of
1:51just liquid media or augur plate or
1:54something like that that you can just
1:55make that viruses will grow on. They
1:58require another organism to grow. So the
2:01most common techniques for this
2:04is live animal inoculation. So that's
2:07exactly what it sounds like. You infect
2:10a live animal. So this would be like
2:13what you see in like mice labs and stuff
2:15like that. A lot of times that's how
2:17they grow viruses is they grow them
2:20inside of living organisms.
2:24You can also grow organisms inside of
2:27embryos. And this is actually how most
2:30flu vaccines are made. Flu vaccines in
2:34order to make the flu vaccines that we
2:37all get every year or you should get
2:39every year. um the flu vaccines that we
2:41all get every year is they have to grow
2:45millions and billions and billions and
2:47billions of particles of the flu first.
2:50And the way that they do that is they
2:52inject it into
2:55fertilized chicken eggs. You can see
2:57down here they inject them into
3:01fertilized chicken eggs
3:04and those that those chicken eggs are
3:06living organisms in there. Okay? And so
3:09the flu virus grows inside of the
3:12fertilized chicken egg or the chicken
3:14embryo and eventually they will harvest
3:18those flu viruses from the chicken eggs
3:21and that's how they make the vaccines.
3:25Um and then another way of doing it and
3:27probably this is the most common is
3:30through cell culture. And cell culture
3:33is a culture. It's keeping alive um
3:38usually human cells.
3:50So it is possible to take a small bit of
3:54human cells just like skin cells or any
3:56other type of cells and it is possible
3:59to grow them in a petri dish if you give
4:03them the right food. The thing that's
4:05really tricky with human cells though is
4:07most of them are not going to grow for
4:08very long, right? Most of our cells are
4:11not designed to stay alive indefinitely.
4:14They will die eventually. They don't
4:17take very long. Um,
4:19most like regular human cells will stay
4:22alive for a couple of weeks at most.
4:25Um, and the other thing that's tricky
4:27about cell culture, which we'll talk
4:28more about on the next slide, is that
4:30cell culture is really, really
4:31difficult. And human cells are really
4:34hard to keep alive. Right? Again, with
4:36bacteria, I can put some of those
4:38bacterial plates. You can forget a
4:41bacterial plate in the back of the
4:42fridge for literal months up to years
4:46and you can come back and sub it and
4:48it'll be like it never stopped growing.
4:50It'll stay alive in there. It basically
4:53goes to sleep and it'll stay alive in
4:56there for a really long time. But human
4:59cells or in cell culture, you have to
5:02feed them every day or so. I remember I
5:06used to work in a human cell culture lab
5:08and there was a story when I lived in
5:10Kansas. There was a blizzard and I had
5:14to walk to campus. I was working on the
5:16University of Kansas campus and I had to
5:18walk to campus. It was like two miles
5:20because I had to go feed my cells
5:23because if I didn't I was going to lose
5:25eight months worth of research. And so I
5:28had to haul my butt through the snow.
5:30I'm a California girl, right? We don't
5:31do snow. I had to haul my butt through
5:33the snow to try to feed my cells because
5:37if I didn't, they were all going to die,
5:39right? Bacteria are not that picky.
5:41Bacteria will stay alive for a really
5:43long time. But cell culture is a very
5:45delicate, it's an incredibly precise and
5:48incredibly expensive process.
5:52So all this to say that viruses are much
5:55more difficult to keep alive
5:58in labs. And that is why for the most
6:01part like hospital labs don't actually
6:05keep viruses alive. When we're testing
6:08for viruses in a hospital lab, most of
6:12the time it's a swab and a quick test,
6:14right? We're not trying to grow it.
6:16We're doing a swab up your nose to test
6:18for DNA, which we'll get there later.
6:20But
6:22um at this point, it's just important to
6:24know that viruses are difficult to grow.
6:27They require expensive processes, a lot
6:30of time. Um, you're either growing live
6:34organisms, live animals, or your
6:36embryionic chicken eggs, or human cells,
6:40all of which require time, energy, and
6:42money to grow.
6:45Okay.
6:47Now, something I like to talk about at
6:48this point in time is something called
6:51helila cells. And some of you may be
6:52familiar with this story. I think it's
6:54become much more popular since the book
6:56came out, but
6:59um I like to talk about stuff like this.
7:01Sometimes it's hard to talk about stuff
7:03like this um because it's hard to admit
7:05when people have done really bad stuff,
7:08right? And there's a lot of really bad
7:09stuff that humans have done to other
7:11humans. And this is a really great
7:13example. Um so Hila cells, what Hila
7:16cells are is they are an immortal cell
7:19line used in cell culture.
7:22Like I said, if I was to take any sample
7:25of any of your cells, if I was just to
7:27like swab your cheek, we could culture
7:30those. We could grow them in a petri
7:32dish, but they would die after a couple
7:34of days. Okay? Most human cells are not
7:38meant to stay alive forever. Even inside
7:41of our own bodies, most of our cells
7:44reproduce and die, right? We create new
7:47ones and the old ones die. I think
7:49there's like an old saying that you're a
7:51new person every couple of months
7:52because every cell in your body is
7:54replaced every few months, right? Your
7:56cells don't stay alive for very long.
7:58They're not meant to. But this specific
8:02type of cell, this cell line is what we
8:04call an immortal cell line. And that is
8:07because it lives forever. It is a
8:12cancerous, it's an unusual cell that was
8:15collected from somebody in the 1950s.
8:19And this cell line is still growing, 70
8:23years later. It's still alive. Now
8:26what's bad about this or what is
8:29controversial
8:30I like to think it's pretty universally
8:33bad when we think about it um is that
8:36helila cells is used to grow the the
8:39impact of helila cells is impossible to
8:42for me to convey in a couple of
8:44sentences. It is used worldwide to grow
8:47viruses for research vaccine production
8:50countless other ways. Millions of
8:52researchers use kila cells every single
8:55day. the discoveries and the scientific
8:58breakthroughs that have come from Hila
9:00cells. Again, it's impossible for me to
9:01tell you all of them. We would be here
9:03forever.
9:05Scientific history as we know it would
9:08not be the same if these cells didn't
9:10exist. Now, what's bad about it is that
9:13these cells were first isolated in 1951
9:17from a woman named Henrietta Alax.
9:19That's why they're called Hila cells
9:20because it came from Henry Alax. The bad
9:23part of this situation is that Henrietta
9:25Alax was a very very sick woman. She had
9:28a really really bad form of cervical
9:31cancer and she died shortly after her
9:34diagnosis of cervical cancer. And
9:36Henrietta Alax was a relatively poor
9:38black woman who went to see a rich white
9:41doctor who took her cells without her
9:43permission. He took a sample of her
9:46cancer and grew it and realized what it
9:49was and made billions of dollars off of
9:52it while she had no idea and then died.
9:58And I think very very recently
10:02uh her family was finally compensated
10:05for this. But that was almost 70 years
10:08after it happened. Her family has been
10:10fighting this battle for a really long
10:12time trying to get compensation for what
10:16was done to their mother back in the
10:191950s.
10:20Now, this is, you know, there are whole
10:22ethics classes that could be taught on
10:24this book alone because like right now
10:28looking at it, that's an objectively bad
10:30thing to do, right? There are all kinds
10:33of pro protections put in place now that
10:36nobody can take any part of your body
10:38without your permission. So if you were
10:41dead and somebody needed one of your
10:42organs, they still couldn't take it
10:44unless you gave permission or somebody
10:46in your family gave permission. Right?
10:48Even you as a dead person have rights to
10:52your own body.
10:54And there are a lot of laws put in place
10:56to protect that. Um, so if this happened
10:59now, unequivocally this would be enti
11:03super illegal, right? However, at the
11:06time those laws didn't exist. Now, does
11:09that make it right? No. It still feels
11:11gross, but at the time it wasn't
11:13illegal.
11:15Um, and it also, you know, when we were
11:18talking about how like should her family
11:21be compensated, probably. Yeah. I mean,
11:24I don't think that there's many people
11:25that would say no, her family shouldn't
11:27get compensation for that. But the hard
11:30part about it is where does that
11:31compensation come from? Because it's not
11:34one company that uses Hila cells. Helila
11:37cells are used by billions of companies,
11:39not billions, it's used by hundreds of
11:41different companies. Um, it generates
11:43revenue of billions and billions of
11:45dollars, but it doesn't come from one
11:48single place. So, it's not like we could
11:50say this company owes them money. So,
11:53who owes them money? Who should give
11:54them money? Um, like I said, and I don't
11:58think that there are clear answers to
12:00that. Um, and I don't think there needs
12:02to be, but I think it's something that
12:04is interesting to think about. Again,
12:06um, people do a lot of really bad stuff
12:09to each other. I think it's important to
12:11talk about that kind of stuff, even when
12:13it's hard, right? This is what happens
12:15to a poor black woman in the 50s when
12:17she goes to see a rich white man.
12:21um
12:22bad things can happen and things like
12:24this happen all the time. Maybe not to
12:25this extent, but people are taken
12:27advantage of and treated poorly for all
12:30kinds of reasons even to today. I know
12:32you guys all saw about that video that
12:34happened on campus, right? So, this is
12:36not something that just happened in the
12:381950s. This is something that still
12:40happens to this day. And so, it's
12:43important to have these kind of
12:44conversations. I didn't see the video.
12:46So you guys can go check your emails if
12:48you That's all I know about it. It's all
12:50over social media. You guys probably
12:51know more about it than I do. But
12:54um
12:56yeah, so just think about it. There's,
12:58like I said, there's no necessarily
13:01right answers in this situation. It's
13:02just important to think about this kind
13:04of stuff. Think about what you think
13:07about it, how we could change those
13:09types of situations. um if you want to
13:11be nurses and caregivers moving forward,
13:14how you can reframe your view to maybe
13:17include other people,
13:21right? And then I just very briefly want
13:24to talk about something called prons.
13:26Now prons are another type of ascellular
13:35um infection. Okay. So prons
13:41are ascellular which again means not
13:44made of cells like viruses they are not
13:46made of cells. Pons are an even more
13:50simple form of organism or not an
13:53organism. Pons are simply misfolded
13:57proteins. Okay? They don't have there's
14:00no genetic material in a pron. There's
14:03not even multiple proteins. It is one
14:05protein that is in the wrong shape. And
14:09what's really bizarre about prons is
14:11they act like they're alive. Because
14:14what happens is when a misfolded pron
14:20protein, that's all it is. It's one
14:21single protein that has folded
14:23incorrectly. When it touches another
14:26protein, it can make that one misfold
14:29and then it can make another one
14:30misfold. Right? So, it acts like a
14:33living organism because it spreads like
14:37an infection,
14:39but all it is is a protein.
14:44Um, and pron diseases are
14:49pretty gnarly in general just because
14:50there's there's nothing to be done about
14:52them. Um, pron diseases are almost
14:55always fatal. um they cause usually
14:58these misfolded proteins are in the
15:00brain and eventually they will cause
15:03permanent brain damage and the brain is
15:05slowly degenerated until it no longer
15:08works. Um
15:10the most common causes of pron diseases
15:13are genetics. There are some people that
15:15just have these misfolded proteins.
15:17That's very very rare. It's not a very
15:20common thing, but there are some people
15:22who are just born that way. they just
15:24have this predisposition to misfolded
15:27proteins.
15:28Um it can happen because of transplants
15:30from an infected individual. So if
15:33somebody has prons in their liver or in
15:37their heart or their kidneys and that
15:40organ gets transplanted into somebody
15:43else that can cause a pron disease in
15:46the receiver. It can also happen um not
15:50just from tissue but blood as well.
15:59There is a if you ever donate blood to
16:02be used like if you ever go to life
16:04share like the plasma center they don't
16:07use their blood if you donate blood at
16:09the plasma center they give you money
16:11right they that's why most people go
16:13there because they pay you when somebody
16:15pays you for organs or tissue or blood
16:19it cannot be used in another human it's
16:21illegal so when you go to the plasma
16:23center that blood that plasma is being
16:25used for research it's not going to
16:27another person But if you ever go to
16:29LifeShare and donate blood to be used in
16:32another person, um there's like a series
16:35of questions that they ask you if you've
16:37ever done this. You guys are a little
16:38young. You kind of only just became
16:40eligible to it. But if you ever go
16:42donate blood at LifeShare,
16:44um there's like a questionnaire at the
16:46beginning and there's one question
16:48there. There's a couple questions about
16:50did you spend I don't remember the exact
16:53numbers but it's like did you spend more
16:54than six months um in England between
16:581980 and 1985 or something like that and
17:02the reason for that is because between
17:041980 and 1985 there was an outbreak of
17:07pron diseases in England
17:11and if you were there for longer than 6
17:13months you are too high a risk to donate
17:16blood because you may have a pron
17:19disease. Now, most of you were not alive
17:21in 1985,
17:22but
17:24um some people might be
17:27um but that's why those questions are
17:29there. You can transfer prons through
17:32blood and other tissues. Um and you can
17:35also get pron diseases from eating
17:38infected tissue. Now, it's not very
17:40common for people in the US to eat
17:42brain. Um but it is common in other
17:44parts of the world. And prons can also
17:47be in other parts of the body. It's just
17:50most common in the brain.
17:53Um so one of the most
17:59kind of um
18:01common names that is associated with
18:04this pron disease that you may have
18:06heard of before.
18:08It's called mad
18:11cow disease
18:15and it is mad cow disease is a pron
18:18disease. It is caused by these misfolded
18:21proteins. Um and it's a progressive
18:24degenerative pron disease which
18:25basically means that it causes the brain
18:27to progressively shrink and look like a
18:31sponge.
18:32Right? So most brain tissue is supposed
18:34to look like this right at the bottom.
18:37It's kind of a solid mass. And then you
18:40can see these are positive samples. And
18:42you can see the big holes. Those are not
18:45normal. Your brain's not supposed to
18:47have holes in it.
18:49And so the prons, what they're doing is
18:51they basically fold and clump together.
18:53That's what all these dark spots are and
18:56they cause the brain to progressively
18:58get worse until it no longer functions.
19:00It's like a form of dementia. It can
19:02kind of seem like Alzheimer's sometimes.
19:06Um, and the biggest outbreak of this
19:08disease, that's called Kitzfeld Yakob
19:11disease. You wondered how to say that,
19:12Kitzfeld Yakob. I'm never going to ask
19:14you to spell it, but that's how you say
19:15it. Um, occurred when a herd of cows in
19:19the UK became infected in the 1990s, and
19:22that was there was a mad cow disease
19:24outbreak, and you could get mad cow
19:26disease or this pron disease by eating
19:30the meat of these infected cows.
19:33Um, and the thing that can be really
19:35scary about it is because
19:38um, it's not a bacteria or a virus, it
19:41doesn't die. So, cooking it doesn't
19:44really help. Even if you cook the meat,
19:46it doesn't really make the pron go away.
19:52So, that's our other example of an
19:54ascellular infection. Our two big
19:56categories of ascellular infections are
19:59viruses and prons.
20:05All right.
20:08Okay. All right. So, I did just want to
20:10cover that last little bit, but now
20:13we're going to be moving on to our next
20:16little module.
20:18Um, and the first module we talked about
20:21for exam number one. It was mostly
20:23focused on the basics of cells, how
20:27cells function, the different types of
20:28cells, um where those cells fall in the
20:32different domains, the structures
20:33associated with specific types of cells.
20:36Now, we're going to talk about how cells
20:40live, I guess, and how they survive in
20:43their environment, what things they eat,
20:45how they get energy, um what types of
20:48environments they have to live in,
20:50things like that.
20:54Okay. So, chapter six, we're going to be
20:56talking about microbial nutrition and
20:59growth. So, how microbes get their food,
21:02how they eat, how they get their
21:04nutrition, and how they grow.
21:09Okay. So, what microbes eat? When it
21:12comes down to it, all organisms, not
21:15just bacteria, but all organisms require
21:19two things. a source of carbon and a
21:22source of energy. So carbon
21:26is a molecule.
21:50So most organic substances, now organic
21:54is kind of a weird word because in
21:57society, organic, we usually take when
22:00we think of the word organic, we think
22:01of organic food. And that has to do with
22:04the way that it's been processed and the
22:06way it's been grown and the certain
22:07pesticides that have been used.
22:10Um, but that's kind of a weird
22:11definition. In biology and science, what
22:14organic means is organic just means made
22:17of carbon. Okay? And most living
22:20organisms are made up of about 90%
22:24organic molecules.
22:26Um, so that's a lot of carbon. Now,
22:30organic molecules are the things that we
22:32talked about last time. Um,
22:34carbohydrates, sugars, lipids, proteins,
22:37DNA, and RNA. Those are all mostly made
22:41of carbon.
22:43And so in order to make all of those
22:45substances that are incredibly important
22:47to everything that a cell does, a cell
22:50has to have all of those building
22:52blocks. It has to have a source of
22:54carbon. Okay? Remember, if we're talking
22:58about building our Lego tower is like
23:00building those organic molecules, the
23:02carbon is like the Lego bricks. Okay? We
23:05need the thing to build it out of. So,
23:07we need a place to get our carbon and a
23:10place to get our energy.
23:21Remember that building all of those
23:23molecules, building lipids, building
23:25carbohydrates, building proteins
23:27requires energy, right? Remember that if
23:30we're building our Lego tower, it
23:32requires energy to pick up a brick and
23:34stack it on top of the other one. Okay,
23:36that's always going to require some
23:39amount of energy. So, those are when it
23:42boils down to it, everything that an
23:45organism requires to survive boils down
23:48to they need a place to get carbon and
23:50they need a place to get energy. Now,
23:53where an organism gets their carbon and
23:56energy from is going to help us
23:58categorize them, right? Remember that we
24:00love to categorize stuff. We want
24:02everything to fit in nice little boxes.
24:04And this is another way of putting
24:06things in boxes is understanding where
24:08they get their carbon and where they get
24:10their energy. Okay. So, first we're
24:13going to talk about that energy source.
24:14Where do organisms get their energy?
24:17Well, there are two places, two major
24:19places.
24:22Um,
24:23organisms can either get their energy
24:26from light
24:28or they get their energy from chemicals.
24:31Now, ATP, which we're going to talk
24:32about more later, ATP is the energy
24:36molecule.
24:40We're going to come, we're going to
24:41circle back to ATP, but for now, just
24:43know that that's the energy molecule.
24:45So, there are two places that or two
24:49sources that an organism can use to
24:52produce energy to produce ATP. Again,
24:56the first one is light, typically from
24:58the sun. So the electromagnetic
25:01radiation in light allows them to
25:04produce energy.
25:07And then other organisms use chemicals.
25:11If an organism uses light, we call them
25:14a photo trough. Like a photograph is
25:17what happens when you use light, right?
25:20Um photo that prefix photo means light.
25:24So a photo trough is an organism that
25:27gets its energy from light.
25:30And a cheotroof. Chemo for chemical. A
25:34cheotroof gets its energy from
25:37chemicals. Now chemicals can mean a lot
25:40of things, right? There's a lot of
25:41different types of chemotroofs.
25:45Most chemotroofs.
25:49The most common place for a chemot to
25:52get their energy is from sugar.
25:59Most organisms who are chemotrops get
26:02their energy from different types of
26:04sugars. However, that doesn't mean it's
26:06the only type. There are organisms um if
26:09you know who Dr. Wells is, Dr. Wells
26:11works over in the biology department. He
26:13has a species of archa growing in his
26:15lab that literally gets its energy from
26:17gold. He grows gold particles and he's
26:20able to grow these archa. It's a really
26:22cool experiment. He'll show you if you
26:24want if you ask him.
26:26Um, so he spends thousands of dollars on
26:28gold flakes to grow archa in his lab.
26:32Um, but again, most chemotroofs are
26:35going to get their energy from sugars.
26:37But just keep in mind that chemo
26:39chemicals can mean anything from metals
26:42to gases to sugars, lipids, anything
26:46else.
26:49Okay. Photo gets their energy from
26:52light. Chemo gets their energy from
26:55chemicals.
26:59Now we think about where organisms get
27:01their carbon from, right? That's the
27:04other requirement. Carbon and energy,
27:06the two requirements. So where do they
27:07get their carbon from? Again, there are
27:10two places that people can get or
27:13organisms can get their carbon from. The
27:17first one is they are basically able to
27:20produce their own organic carbon
27:26by pulling inorganic gas out of the
27:29atmosphere. So what these organisms are
27:31capable of doing is taking carbon
27:33dioxide, which is a gas that's floating
27:35around in the atmosphere, and pulling it
27:38out of the atmosphere and turning it
27:40into something physical,
27:42turning it into an organic molecule.
27:46They take something inorganic and
27:48gaseous that's floating around in the
27:50air and turn it into a physical
27:53molecule,
27:55a particle of sugar or something else.
27:58Okay? And they're called auto troughs
28:01because they basically they make their
28:04own food. Auto means self or own, right?
28:08It means self. It means you're doing it.
28:10So an auto trough basically makes their
28:13own food.
28:16Okay, they breathe in gas and they make
28:19food out of that.
28:21Okay, that's why they're called an
28:23autoro. They're also called the
28:25producers because they produce their own
28:27food.
28:30Okay, and heterotroofs,
28:33remember hetero as a prefix means other
28:36or different or opposite.
28:38Okay, so heterotroofes obtain their
28:41carbon by consuming other organisms.
28:45They get their food by consuming other
28:47organisms.
28:49Okay. And heterotroofs are also
28:51sometimes called so autooughs are
28:53sometimes called the producers because
28:56they make their own food. Heterotroofes
28:58are sometimes called the consumers
29:04because they consume other organisms to
29:06get their carbon.
29:11Okay. And most people when they think of
29:13auto troughs they think of
29:15photosynthesis,
29:17right? Which is using carbon dioxide and
29:20light to produce energy in food. Okay.
29:24So any organism that can do any kind of
29:26photosynthesis is going to be an auto
29:29trough. That's what a photosynthetic
29:31organism is doing is they're taking
29:34carbon dioxide out of the air and
29:36turning it into food.
29:39And the consumers are the organisms that
29:42eat the other that eat the producers
29:45usually.
29:49Okay.
29:53Now, with those two different things,
29:55right, we had the energy source, we have
29:57a carbon source. There's two types of
29:59each. There's four total possible
30:02combinations,
30:04right? So, if an organism gets its
30:07energy
30:09from chemicals,
30:12there are two different ways for it to
30:13get its carbon, right? So, these are the
30:16if you look at the chemotra first places
30:18to get their chemicals. If they get
30:20their
30:22carbon from CO2, then you combine those
30:25two words and they're a chemo autotroof,
30:29right? Because they got their energy
30:30from chemicals which made them cheot.
30:35And they got their carbon from
30:37themselves. They pulled it out of the
30:39atmosphere.
30:42So they were auto
30:44self. They made their own food. They're
30:46a producer. So you put those two words
30:48together and they're a chemo autotroof.
30:52Okay. If an organism gets its energy
30:55from chemicals, it's still chemo, but it
30:58gets its carbon from organic molecules
31:00by consuming other organisms, which we
31:03called a heterotroof.
31:07You put those two words together, you
31:08get a chemoheterotroof,
31:13right? And then the same goes for when
31:14an organism gets its energy from light.
31:17If it gets its energy from light, we
31:19called it a photo troof.
31:23If it gets its carbon from inorganic
31:26sources like carbon dioxide, if it makes
31:28its own food, we call it an autoro. So
31:32an organism capable of those two things
31:35getting its energy from light and its
31:37carbon from carbon dioxide, we call it a
31:40photoroof.
31:41Put the two words together and then our
31:44last one.
31:47If it gets its energy from light and its
31:50carbon from organic sources by consuming
31:53other organisms, you have a photo
31:55heterotroof.
31:58Now, there are organisms in all of these
32:01categories, right? You can see that
32:03there are some examples down here. The
32:05most common two though are going to be
32:09these two.
32:12Okay, the other two exist. There are
32:14organisms that do that, but they are
32:16much less common. Most organisms are
32:19going to be cheoeterotroofes
32:22or photoroes,
32:25meaning chemoheterotroofes again are
32:27organisms that consume other organisms
32:32to get ener to get carbon and they get
32:35their energy from chemicals.
32:38um usually accomplished by consuming
32:42other organisms, right? It's a two for
32:44one deal. So chemoheterotroofes are
32:47things like animals, right? We as a
32:50human are chemo heterotroes. Where do
32:53you get your energy and food from? You
32:55eat other things. You eat other animals
32:57or other vegetables or fruit, right?
33:02Um, you consume other organisms, not
33:05just living organisms, but or not just
33:08animals like most people I say that they
33:10consume other organisms. Most people
33:11think of animals, but plants and fruits
33:15and vegetables, all that stuff. Those
33:16are organisms too. But you get your food
33:20and energy and everything that you need
33:22by consuming other organisms. You are a
33:25cheeter.
33:28Okay. Our other major category are the
33:31photo autoroes. These are usually the
33:33organisms that can do photosynthesis
33:35like plants and algae. They use light
33:39energy and they pull gas out of the
33:41atmosphere and make food that way
33:45which is pretty cool. I wish I could do
33:46that. But
33:49um most of our
33:52pathogenic bacteria
33:56are also going to be
34:10most pathogenic bacteria are going to be
34:12cheo heterotroes which makes sense if
34:15you think about remember a pathogenic
34:18organism is an organism that causes
34:20disease. Specifically in this class
34:23we're talking about organisms that cause
34:25disease in humans.
34:28Most human pathogens are
34:30chemoheterotroes.
34:31That's why they grow inside of us. It's
34:34because they are eating us. They're
34:36consuming us as their food source. So
34:39most and don't get me wrong, there are a
34:41lot of bacteria that exist outside of
34:45this and things like that. But what
34:47we're focusing on this class, the
34:49pathogenic organisms are cheopetroes.
34:53They get their carbon and their energy
34:56from us. That's why they're living
34:58inside of us. That's why they're harming
35:00us. They're not harming us because they
35:02like it, because they want to. They're
35:05harming us because we're their food
35:06source, right? They don't they don't
35:09have feelings about it. They just eat us
35:11because that's what they want to eat.
35:12That's what provides them their
35:14nutrition.
35:16So that's why they cause disease in
35:18humans because we are their food.
35:26Okay.
35:29So now we're going to talk about how
35:30microbes eat. Right. When we talk about
35:32eating, most of us think about how
35:34animals eat because that's what we're
35:36most familiar with, right? How animals
35:38eat. We put food in our mouths. We
35:40digest it through our digestive tract,
35:42things like that. Bacteria and most
35:44microbes don't have those things. So,
35:47how do they eat when they don't have
35:50mouths or digestive tracts? What how
35:52does the food get inside of them?
35:55Right? And that is going to be through
35:58different types of transport. So, how do
36:01we get these large molecules, things
36:04like sugars and metals and proteins? How
36:08do they get from outside the cell to
36:11inside the cell?
36:13Because remember, we talked about that
36:15these membranes
36:18are semi-p permeable.
36:22These are cell membranes. So, a bacteria
36:24for the most part is only getting to be
36:26one cell big. So, how does this one cell
36:30get stuff from outside to inside when
36:33that membrane is not going to let things
36:35through? Remember, semi-permeable means
36:38that only some things can get through
36:39the membrane. Usually, very tiny things
36:42like water, maybe some salts, some
36:45electrolytes, but that's kind of it.
36:47Anything bigger than that, a sugar, a
36:49fat, a protein, is never going to be
36:52able to cross the membrane. That's way
36:54too big. So how do things cross
36:57membranes? How do organisms get the
37:00sugars and the fats and the proteins
37:02that they need if they cannot consume
37:05them? And the answer is that they do.
37:08They just consume it in different ways
37:10than we would typically think of as
37:12consuming.
37:15So before we get to like the details of
37:18that, want to talk about something
37:20called diffusion. Now, what diffusion is
37:23is it's the movement of molecules from
37:27high concentration to low concentration.
37:30High concentration just means where
37:31there's a lot
37:39to where there's a little.
37:48Okay.
37:50And this is due to I'm going to try to
37:52keep this as simple as possible. It's
37:54hard not talking about all the details
37:57of it. Um, but keep in mind when I talk
38:00about this that there's a lot of things
38:02under the surface that we're just not
38:03talking about, right? Thermodynamics and
38:06chemistry and things like this,
38:07thermocinetics are insanely complicated
38:11and we're just we're kind of brushing
38:12over it. So, there may be some things
38:15that don't completely make sense to you.
38:17It's because there's a ton of stuff
38:19underneath the surface that we're just
38:20not going to talk about. So, for a lot
38:22of reasons that we're not going to talk
38:24about that have to do with electrons and
38:26the randomness of the universe and all
38:27kinds of things like that, there is a
38:29truth in the universe, in science, in
38:33life that things are always going to
38:36move to equilibrium.
38:40Molecules and things inside a system
39:04Molecules inside a system want to be at
39:07equilibrium. And what equilibrium just
39:09means is equilibrium just means
39:11balanced. They want to be spread out so
39:14that they're even.
39:16Okay? Even a really good example, and
39:19this is true for any system and any size
39:22molecules, is that things are going to
39:24move around until they're even, if they
39:27are able to. When all things are
39:29allowing them to move, things are going
39:31to move until they're even. And this
39:33even applies to like our own psychology,
39:36right? Look around this room. There's a
39:38lot of seats, but when you look at you
39:40guys all spread out, you guys tend to
39:43spread out, right? This classroom is
39:45mostly there's people kind of
39:46everywhere. There's a couple spots. This
39:48falls apart a little bit, but for the
39:49most part, if you put 20 people in a
39:52room, they're not going to all stand
39:54next to each other. They're going to
39:55spread out until they're kind of even,
39:58right? Isn't there rules about using the
40:00bathroom, right? Like you never stand
40:02next to somebody else. You spread out,
40:04right? Equilibrium. Everything wants to
40:07even in like our social situations and
40:09social cues, we want to be even.
40:13And you're not going to start filling in
40:16until there's no other room. Okay? So,
40:19if this is true, and this occurs from
40:22everything to people in a classroom
40:26all the way down to individual
40:27molecules, molecules, if they are given
40:30the chance, are going to spread out
40:32until they are as even as they can be.
40:35Okay. And that is what diffusion is.
40:38It's the movement of molecules until
40:41they're at equilibrium, until they're
40:43even.
40:45Okay. And what that means is they're
40:47going to move from a place where there's
40:48a lot of them to places where there's
40:51not as many of them to even it out. So,
40:54a really great example of this is if you
40:56were to take this, and if you've never
40:58done this experiment, you can go home
41:00and do it today. And all you do is you
41:03take a glass of water and you take a
41:05drop of food dye and you put one drop of
41:07food dye. Now, when you first put that
41:09one drop of food dye, it's going to sit.
41:12A lot of times those oil those dyes have
41:15a little bit of oil in them and they'll
41:16like sink to the bottom, right? They'll
41:18just kind of hang out and they'll hang
41:20out in one spot. But if you leave that
41:23glass sitting there for long enough,
41:25eventually those dye molecules will
41:28spread out until they are spread all
41:30over the entire glass. Sometimes it
41:32takes a while. It'll take a couple of
41:34hours probably
41:36if you don't stir it. But you can go
41:38home and do this today. Go find a thing
41:39of food coloring and a glass of water.
41:41Put one drop of food coloring in the
41:43water and you'll see that the color will
41:45eventually leech until it's at
41:47equilibrium. Another really good example
41:50of this is a tea bag in a thing of hot
41:52water. Right? When you first put a tea
41:56bag in a thing of hot water, it turns
41:58the little part where the bag is brown.
42:02But eventually, if you let it sit there
42:03long enough, all the water is going to
42:05turn the same color. Okay? That is
42:08diffusion. It's the molecules moving
42:10around until they're even.
42:15And because this is a property of
42:19molecules and again it has to do with
42:21the movement of electrons and the
42:22randomness of the universe and all kinds
42:24of stuff. This does not require energy.
42:27This is something that will happen
42:30always. There's no energy required. You
42:32put that one drop of red food coloring
42:34in a glass of water and it is going to
42:37happen. Okay? It is the natural state of
42:42anything in a system is to be even. And
42:45so those molecules are always going to
42:48move so that they are even. They are
42:50going to move from high concentration to
42:52low concentration if they can. And it
42:56does not require energy.
42:58Now you can have so this first example
43:01of diffusion is just a thing of dye in a
43:04cup of water.
43:07But you can have diffusion across a
43:10plasma membrane.
43:12But this only happens like this
43:19if and only if the molecule
43:25can move.
43:36Beep.
43:37I got to the end of my
43:40this will only occur across a membrane
43:43if that molecule is capable of moving
43:46across a membrane. So that we talked
43:48about there are a few organism a few
43:50molecules small molecules like
43:52electrolytes and water that are
43:54typically capable of moving across the
43:57membrane on their own.
44:00And if they are able to move, they will
44:04they'll move from an area of high
44:07concentration to an area of low
44:10concentration.
44:12Okay? So these molecules, right, these
44:15purple molecules, there's six outside
44:18and three inside. So these molecules
44:22will move
44:24until they are even on both sides or as
44:27even as they can be.
44:31Okay. But they're always going to move
44:33from high concentration to low
44:35concentration in order to reach
44:38equilibrium
44:40until they reach that equilibrium state
44:42until they're even.
44:48Okay? And again, this does not require
44:50energy
44:52because if a molecule can move across
44:55the membrane, it will from an area of
44:58high concentration
45:01to an area of low concentration.
45:06Okay.
45:09Now, this is this can be kind of tricky
45:11at first, but this is what happens when
45:16water moves across a membrane. And this
45:20is usually because
45:25the molecules
45:28in the water
45:32can't move.
45:36Okay, so a good example of this is like
45:39something dissolved in water like salt.
45:42Okay, salt is too big and too charged to
45:46go across a membrane. Salt is a molecule
45:49like table salt or sugar. Sugar
45:51dissolved in water, right? Anything in
45:55the water is too big to cross. Well,
46:00the system that we are talking about is
46:02still going to want to be at
46:04equilibrium.
46:06Now, again, if these molecules were
46:08capable of moving, they would they would
46:11move across the membrane to balance
46:12everything out. But when they can't, the
46:16water can,
46:19okay? Because the wa the molecules in
46:21the water cannot move.
46:25So when the solutes can't move but the
46:28water can, the water will move from
46:31where there is more water to where there
46:34is less water relative to the stuff in
46:37it. Okay? Now, I know that's weird to
46:41think about because when you look at
46:43this this system right here, this one on
46:46the left,
46:49it looks like on both sides of that
46:51line, on both sides of that membrane,
46:53there's the same amount of water, right?
46:56Because it's at the same level, right?
46:59That's not a straight line, but you can
47:00see what I'm saying. The pink is at the
47:02at the same level, right? So you might
47:05say at first that there is the same
47:07amount of water
47:10and that's kind of true. But the reason
47:13that there is more water on this side is
47:16because there is less stuff in the
47:19water. Okay. So the way I like to think
47:22about this is if you took
47:26um
47:28okay so you have your cup at home.
47:29You're filling up your Stanley in the
47:31morning or your AAL or whatever else you
47:32got. You got your cup in the morning,
47:34you're filling it up. If you fill that
47:37cup up with just water
47:41versus if you stuff that cup full of ice
47:44first and then fill it up, which one is
47:46going to have more liquid water in it?
47:49The one with ice or the one without?
47:51>> The one without. Right? Because that ice
47:54is taking up lots of space. That's
47:56what's happening here at a microscopic
47:58level. There's more ice in this side, so
48:01there's less water. Okay? And if you
48:04just look at the colors on this left
48:06side, there's clearly more pink than
48:08there is on this side. Okay? So, what's
48:11going to happen is because those solutes
48:14cannot move in this scenario,
48:17the water is going to move. So, the
48:20water is moving from where water has the
48:24most to where water is the least. Okay,
48:28so the water will move across the
48:32membrane to balance out the
48:35concentrations. Now, when you first look
48:38at this side over here,
48:41in theory, this side has more water than
48:44this side, right? Because the levels are
48:46different. But if you're looking at the
48:49amount of water like per square,
48:54right? Okay. And that's what we mean by
48:56the concentration is how much there is
48:59per square. So if I was looking at one
49:02little square of four purple molecules,
49:06whatever those are on this side versus
49:08this side, there's the same amount of
49:11pink and purple in both of these
49:13squares, right? It is even. Now it's an
49:17equilibrium. If I was to draw these
49:19squares over here, like if I was to draw
49:22a square that big over here,
49:26okay, you can see that they're uneven.
49:29There's more water and less stuff in the
49:32water over here than there is here. But
49:36after the movement, that little square
49:40has an even amount of water and stuff in
49:43the water on both sides.
49:47Okay. So that is what osmosis is.
49:50Osmosis is specifically the diffusion of
49:53water across a membrane because the
49:57stuff in it cannot move.
50:02So it moves again the water will move
50:05from where there is more water to where
50:07there is less water. it becomes
50:10confusing because if you look at the
50:12stuff that's in the water, you're going
50:14to get confused. Um, when the solutes
50:17can't move or the stuff in the water
50:18can't move, the water will move to
50:20balance it out.
50:22And again, osmosis is just a type of
50:25diffusion.
50:27And this does not require energy.
50:36This is what will happen in a natural
50:38state of being because
50:42everything wants to be at equilibrium.
50:44This is how the molecules will move to
50:46be even
50:55and osmosis is something that happens
50:58all the time in different types of
51:01cells.
51:03Um so what osmosis is again osmosis is
51:08the is the movement of water and this
51:11happens in all different cell types all
51:14the time and there are three different
51:16scenarios that you can have that have
51:18them that cause the movement of water.
51:21So this first one
51:25is what we call an isotonic solution.
51:28And what's happening in an isotonic
51:30solution is that the amount of water is
51:34about the same as the am the amount of
51:37water inside the cell is about the same
51:40as the amount of water outside.
51:44Okay? And so because of that the
51:47diffusion in and out of the cell is
51:49relatively equal. Everything kind of
51:51stays the same. Everything is already at
51:54equilibrium.
51:58Okay. And so when that happens,
52:00everything is relatively stable and the
52:03cell will stay the same.
52:07All right. But what will happen if you
52:10take a cell? We're going to do this one
52:12first because I think this one's easier.
52:14What happens if you take a cell and you
52:16put it in what's called a hypertonic
52:19solution? Now, what hyper means? Hyper
52:22means high
52:24or a lot of,
52:27right? Like if somebody's really really
52:29hyper, somebody's hyperactive, it's
52:30because they got lots and lots of
52:31energy. That's what hyper means. Hyper
52:33means high, a lot of, tons of. So a
52:36hypertonic solution means that there is
52:39going to be more stuff outside the cell
52:45than there is inside the cell. So
52:47outside the cell
52:56has more solutes.
52:59Remember solutes is the stuff.
53:03So more solutes means relatively less
53:08water.
53:11Okay. But when we're talking about this
53:13name, hypertonic means the the stuff in
53:17the water. It's not talking about the
53:18water. It's talking about the stuff in
53:19the water. So hyper means high amounts
53:23of stuff. So there's high amounts of
53:26stuff and less water. And then inside
53:29the cell is the opposite. There's less
53:33stuff,
53:37less solutes, and more
53:40water.
53:43Okay. So in this case when we're talking
53:46about this kind of stuff the solutes
53:48cannot move.
53:50Okay. So because the solutes cannot move
53:53the water is going to move to balance it
53:56out. So where is solutes where is the
53:58water going to move to the inside or to
54:00the outside?
54:04It's going to move to the outside. It's
54:06going to move from where there is more
54:08water to where there is less water.
54:11So it will move from the inside to the
54:14outside. So water is going to flow out
54:17of the cell to try to balance out those
54:19concentrations.
54:24Okay? And what can happen
54:27especially in cells that do not have a
54:31cell wall like human cells,
54:34it can cause the cells to shrink up and
54:37become dehydrated. Now, a really, really
54:40great example of a hypertonic solution
54:43is, have you ever gone to the beach and
54:45spent all day in the ocean and then when
54:48you get home, you feel like every ounce
54:49of water has been sucked from your skin
54:51and you're so dry your lips feel like
54:54they're painted on. Everything is tight
54:57and dry. That's because you have spent
55:00the entire day with your body submerged
55:03in a hypertonic solution. You have been
55:06submerged in salt water. Salt water has
55:08tons and tons of stuff in it. Okay, so
55:12this is an example of
55:16like swimming in salt water.
55:27Because your cells are soaking in a
55:30hypertonic solution all day, the water
55:33diffuses out of your cells into the
55:36environment to try to balance out the
55:38concentrations. So your skin cells feel
55:41extremely dry and they are extremely
55:44dry. Your skin is incredibly dehydrated.
55:49Okay. Now the last one is when you have
55:52what's called a hypotonic solution. Now,
55:55hypo is like hypootherrmia,
55:59right? Hypothermia is being really,
56:00really, really cold. The temperature
56:02drops and gets really, really low.
56:04Hypotonic means low. Hypo is a low.
56:09Okay. So, what's happening here is that
56:12the outside
56:17has less solutes
56:23and more water.
56:26Then the inside the inside
56:30has more solutes
56:36and less water.
56:40Okay. So if that is the case, where is
56:42our water going to move? To the inside
56:44or to the outside?
56:46>> To the inside. It's going to move from
56:47where there's more water to where
56:49there's less water. So the water is
56:51going to flow into the cell.
56:54And what can happen here is exactly the
56:57opposite. The cells will actually fill
56:59up kind of like a balloon and eventually
57:02if they have too much water in them,
57:04they will burst.
57:06Now, this is much less common, but there
57:08is an example of this that can happen in
57:11the real world that is called
57:15water toxicity. Now, this is very, very
57:18rare,
57:20but it is possible to overdose on water.
57:24If you drink a lot of water really,
57:27really, really fast, this can happen
57:29inside your body. Your cells will suck
57:32up all that water and it can eventually
57:35cause your cells to burst. There was
57:36actually a case in it was somewhere in
57:39the US, I don't remember exactly where,
57:41a couple of years ago where a mom had
57:44spent all day at the beach and she
57:46didn't drink any water all day. She
57:47spent all day in the sun. She was really
57:49dehydrated. She probably had a heat
57:51stroke. Um, and so she got home and she
57:54drank like nine bottles of water back to
57:57back to back to back in the span of a
57:59couple of minutes and she actually ended
58:01up dying. It was a really really sad
58:03story. Um, but that is because drinking
58:07that much water made the inside of her
58:09body hypotonic.
58:11And so all of that water flowed into the
58:14cells and burst them open.
58:19So that is tenicity.
58:22All right.
58:24Okay. So we're going to stop lecture
58:26there for the day. Do not pack up. Okay.
58:28We have Miss Jenny Wear here. I told you
58:30we were going to have a guest. So, she's
58:32gonna come talk to you for a few
58:34minutes. There's her flyer.
58:41I don't have a microphone, so you go for
58:43it.
58:44>> Hello. It's not in anymore, but um I
58:47hope y'all are all having a great
58:48Monday. Have a good weekend. Um
58:51actually, just to come by and say hello
58:53and then kind of offer you just words, I
58:56guess. Um if you have not met me, my
58:58name is Jenny. I'm a retention
59:00specialist for our college. I've been
59:01going around to a lot of the FYE
59:03classes. Um so if you're in FYU and I
59:05haven't made it to you yet, I will be
59:06coming most likely. Um but if you need
59:10assistance with um time management,
59:12study skills, or just really anything,
59:13um we have a lot of resources on campus.
59:15Um and if you're not sure what those are
59:17and would like to get connected to some,
59:19I would love to have a conversation with
59:21you. Um, I think y'all had your first
59:23exam recently and if you're like, "Hey,
59:25I studied and maybe I didn't make the
59:27grade that I wanted to make or if you
59:29did make a good grade and you're like,
59:31"Hey, I still want to improve my study
59:33skills." If it's whether this class or
59:35another one, um, again, love to have a
59:37conversation with you. So, um, you can
59:38scan that QR code. It will take you
59:40directly to my booking link. If there's
59:42not a time that fits with your schedule,
59:45um, please send me a text message or an
59:47email and I will work with you to try to
59:50figure something out. But um just wanted
59:52to again introduce myself, let you know
59:53that I'm here as a resource for you. I'm
59:56also hosting a study skills and time
59:58management workshop on October 9th, I
1:00:02believe is the that one is. Um it's
1:00:04going to be in the library at 12:30.
1:00:07That's a Friday before um our football
1:00:09game next week.
1:00:11>> I can I can send out that she I'll email
1:00:14everybody the fire for that.
1:00:15>> He has that. Um, so if you're like, hey,
1:00:17I don't have time for oneonone session,
1:00:19but we like to cover that. There are
1:00:21going to be some small giveaways for
1:00:22that. And then there's going to be
1:00:23another one in November on the 5th. So
1:00:25like connection, so if you would like to
1:00:27meet some other people across our
1:00:29college specifically, maybe not just in
1:00:31your major um
1:00:34students in applied medical sciences and
1:00:37in some of our
1:00:43>> All right. Thank you, Jenny.

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