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AP Bio Macromolecules - Part 2 | This is the piece of any piece of nucleic acid. |
AP Bio Macromolecules - Part 2 | These are the smallest pieces. |
AP Bio Macromolecules - Part 2 | They're going to be composed of three different things, a phosphate group, which you guys have probably seen in chemistry, if you have 4, 3-, a pentose sugar, which is oftentimes drawn kind of like this, where each of the corners symbolizes a carbon. |
AP Bio Macromolecules - Part 2 | We won't worry about the other molecules and atoms that are part of it. |
AP Bio Macromolecules - Part 2 | So that'll be the pentose sugar. |
AP Bio Macromolecules - Part 2 | And then it has a nitrogenous base, which will be a base that's either a pyrimidine, long name, which means short structure in my memory. |
AP Bio Macromolecules - Part 2 | I always remember it's the opposite, so big name, it's the smaller one. |
AP Bio Macromolecules - Part 2 | They're composed of one ring. |
AP Bio Macromolecules - Part 2 | And then there'll be purines, small name, which are the bigger structure. |
AP Bio Macromolecules - Part 2 | There are two rings. |
AP Bio Macromolecules - Part 2 | And there's in DNA four overall nitrogen bases, cytosine, thymine, adenine, guanine. |
AP Bio Macromolecules - Part 2 | And what'll happen is when you talk about RNA, instead of thymine, it will have uracil. |
AP Bio Macromolecules - Part 2 | That's really the only difference. |
AP Bio Macromolecules - Part 2 | They still have cytosine, adenine, and guanine, but when it comes to nitrogen bases, that's the only difference. |
AP Bio Macromolecules - Part 2 | Now, speaking of DNA and RNA, there is one other difference besides the thymine and uracil, and that's that they also have a different pentose sugar. |
AP Bio Macromolecules - Part 2 | They both have a pentose sugar. |
AP Bio Macromolecules - Part 2 | They just have a different one. |
AP Bio Macromolecules - Part 2 | Specifically, DNA has one that's missing an oxygen, deoxy, so without oxygen. |
AP Bio Macromolecules - Part 2 | Otherwise, it's identical. |
AP Bio Macromolecules - Part 2 | But because it's different, because it's missing that oxygen, they get their different names. |
AP Bio Macromolecules - Part 2 | Now, the significance of this is I can't take an adenine nucleotide that also has a phosphate and a sugar. |
AP Bio Macromolecules - Part 2 | I can't take that if it's RNA, and I can't exchange that with one that's DNA. |
AP Bio Macromolecules - Part 2 | I can't assume that they're the same. |
AP Bio Macromolecules - Part 2 | Because even though the adenine and the phosphate are the same, this sugar will be different. |
AP Bio Macromolecules - Part 2 | One will be ribose, one will be deoxyribose. |
AP Bio Macromolecules - Part 2 | So DNA and RNA nucleotides, even if they contain the same nitrogen base, are not interchangeable. |
AP Bio Macromolecules - Part 2 | The other word you might see is nucleoside instead of nucleotide, and this is just when we kind of ignore the phosphate aspect. |
AP Bio Macromolecules - Part 2 | You'll see there are other molecules that are derived from nucleotides that we will talk about. |
AP Bio Macromolecules - Part 2 | ATP, for instance, an energy molecule, and ADP, both are essentially derived from a nucleotide. |
AP Bio Macromolecules - Part 2 | And so we will talk about some of these other guys. |
AP Bio Macromolecules - Part 2 | And so a nucleoside is kind of like the base unit of that, where it's just a nitrogen base and a sugar. |
AP Bio Macromolecules - Part 2 | So it can't get a whole lot simpler and resemble much of a nucleotide at all. |
AP Bio Macromolecules - Part 2 | So that's a nucleoside. |
AP Bio Macromolecules - Part 2 | Over here too, you can see RNA has one strand, DNA has two,
and those two strands will be hydrogen bonded together here in the center. |
AP Bio Macromolecules - Part 2 | We'll talk about that coming up here in just a second. |
AP Bio Macromolecules - Part 2 | Oh, and you can also see this is going to be the long names, the pyrimidines. |
AP Bio Macromolecules - Part 2 | This will be a purine, and you can just see they've got like these two rings versus one ring. |
AP Bio Macromolecules - Part 2 | So when I was talking about that, that's what they're talking about. |
AP Bio Macromolecules - Part 2 | Okay, and then the last bit here is just that these guys, these perhaps handsome British devils,
I don't know if that's an actual oxymoronic phrase there, but they're Watson and Crick. |
AP Bio Macromolecules - Part 2 | All right, and these guys in the 50s came up with a structure of DNA. |
AP Bio Macromolecules - Part 2 | That's the double helix. |
AP Bio Macromolecules - Part 2 | We just showed it on the last slide. |
AP Bio Macromolecules - Part 2 | We talked about the hydrogen bonds that are between those nitrogen bases. |
AP Bio Macromolecules - Part 2 | So as those bases kind of stick out from the ladder, if you will. |
AP Bio Macromolecules - Part 2 | I'm not drawing this twisted because I can't draw that well. |
AP Bio Macromolecules - Part 2 | So these would be the nitrogen bases that would be in the center, and there'd be hydrogen bonds that are holding them together. |
AP Bio Macromolecules - Part 2 | Sometimes they're shown as like dotted lines all along the center of the thing here, the middle of the ladder. |
AP Bio Macromolecules - Part 2 | And they do so in a way that's called complementary paired or complementary pairing occurs. |
AP Bio Macromolecules - Part 2 | And what that means is adenine, the nucleotides that contain adenine, only want to bind with the nucleotides that contain thymine. |
AP Bio Macromolecules - Part 2 | So if this guy has an adenine, this one would be thymine. |
AP Bio Macromolecules - Part 2 | And the ones that have guanine only want to pair up with the ones that have cytosine. |
AP Bio Macromolecules - Part 2 | And so this helps and help them, I guess, but helps us to figure out how DNA replication occurs, which is when we copy DNA,
which is critical for the function of reproduction because you need two copies to give one to your offspring. |
AP Bio Macromolecules - Part 2 | And so by having this system in place, by discovering this, it made it pretty easy that I could kind of get rid of this strand. |
AP Bio Macromolecules - Part 2 | And I could rebuild the new one because A would want to get with a new T partner, even if you took away the original. |
AP Bio Macromolecules - Part 2 | C would still want to only get with guanine. |
AP Bio Macromolecules - Part 2 | T would only want to get with A, et cetera. |
AP Bio Macromolecules - Part 2 | And so you could rebuild a new strand that was just like the old one, accurately, efficiently, without many errors, ideally without any. |
AP Bio Macromolecules - Part 2 | But let's face it, there are mutations. |
AP Bio Macromolecules - Part 2 | It does happen. |
AP Bio Macromolecules - Part 2 | And so that's the idea here. |
AP Bio Macromolecules - Part 2 | And that's ultimately why they were able to win the Nobel Prize when they discovered this and for their discovery. |
AP Bio Macromolecules - Part 2 | So at this point, we've wrapped up proteins and we've wrapped up nucleic acids. |
AP Bio Macromolecules - Part 2 | That's it for macromolecules for now. |
AP Bio Macromolecules - Part 2 | We're going to talk about enzymes coming up before we get into cells. |
AP Bio Macromolecules - Part 2 | I hope you've enjoyed this. |
AP Bio Macromolecules - Part 2 | Have a good night. |
Eukaryotic Cells Part 1 Animal Cells and Endosymbiotic Theory | Professor Dave here, let's talk about animal cells. |
Eukaryotic Cells Part 1 Animal Cells and Endosymbiotic Theory | We now know the basics about prokaryotic cells, but cells get much more complicated than this. |
Eukaryotic Cells Part 1 Animal Cells and Endosymbiotic Theory | Human beings and all other animals are made of eukaryotic cells, which contain a number
of components called organelles that are not present in prokaryotic cells, some of which
resemble individual organisms unto themselves. |
Eukaryotic Cells Part 1 Animal Cells and Endosymbiotic Theory | Because they are more complex, we know that eukaryotic cells evolved from prokaryotic cells. |
Eukaryotic Cells Part 1 Animal Cells and Endosymbiotic Theory | Endosymbiotic theory proposes that billions of years ago there were many different types
of bacteria floating around, all of which were unicellular. |
Eukaryotic Cells Part 1 Animal Cells and Endosymbiotic Theory | Some of these species of bacteria acquired unique functions, like the ability to perform
photosynthesis or breathe oxygen. |
Eukaryotic Cells Part 1 Animal Cells and Endosymbiotic Theory | It is believed that larger host cells then enveloped some of these smaller bacteria,
and instead of digesting them, a mutual dependency arose, each relying on the other for some
crucial function. |
Eukaryotic Cells Part 1 Animal Cells and Endosymbiotic Theory | The smaller cell received protection, while the larger one reaped the benefits of some
kind of energy-producing process. |
Eukaryotic Cells Part 1 Animal Cells and Endosymbiotic Theory | This is where the name endosymbiotic comes from. |
Eukaryotic Cells Part 1 Animal Cells and Endosymbiotic Theory | Endo means inside, and symbiosis refers to organisms living and working together. |
Eukaryotic Cells Part 1 Animal Cells and Endosymbiotic Theory | These smaller bacteria grew more specialized over millions of years of evolution, and eventually
became some of the organelles we find within a single eukaryotic cell. |
Eukaryotic Cells Part 1 Animal Cells and Endosymbiotic Theory | So what are these organelles exactly? |
Eukaryotic Cells Part 1 Animal Cells and Endosymbiotic Theory | To answer that, let's first make the distinction between plant cells and animal cells. |
Eukaryotic Cells Part 1 Animal Cells and Endosymbiotic Theory | These are both examples of eukaryotic cells, but they differ in the precise components within. |
Eukaryotic Cells Part 1 Animal Cells and Endosymbiotic Theory | Let's first take a look at animal cells, which are the kind inside you and me, since
humans are considered part of the animal kingdom. |
Eukaryotic Cells Part 1 Animal Cells and Endosymbiotic Theory | The first thing we want to point out is that while prokaryotic cells have their genetic
information just floating in the middle of the cell, eukaryotic cells store their genetic
information inside a nucleus. |
Eukaryotic Cells Part 1 Animal Cells and Endosymbiotic Theory | This nucleus has its own membrane, which unlike the cell membrane, is actually a double membrane,
and this nuclear envelope only lets certain things in or out by passing through tiny holes
called pores. |
Eukaryotic Cells Part 1 Animal Cells and Endosymbiotic Theory | In this way, it keeps all the genetic material, or chromatin, separate from the cytoplasm
of the cell. |
Eukaryotic Cells Part 1 Animal Cells and Endosymbiotic Theory | Within the nucleus is a smaller area called the nucleolus, where ribosomal RNA is synthesized,
as well as the parts of the ribosomes themselves. |
Eukaryotic Cells Part 1 Animal Cells and Endosymbiotic Theory | The large and small subunits of the ribosome are formed, which then exit the nucleus and
assemble in the cytoplasm. |
Eukaryotic Cells Part 1 Animal Cells and Endosymbiotic Theory | Some of these ribosomes can be found floating around in the cytosol, but some are stuck
to the surface of the nucleus, or other organelles, like barnacles on a boat. |
Eukaryotic Cells Part 1 Animal Cells and Endosymbiotic Theory | Ribosomes, which are present in both prokaryotic and eukaryotic cells, are made of ribosomal
RNA and proteins, and these in turn synthesize all the proteins the cell needs to perform
its various functions. |
Eukaryotic Cells Part 1 Animal Cells and Endosymbiotic Theory | Other components of the cell come together to make up the endomembrane system. |
Eukaryotic Cells Part 1 Animal Cells and Endosymbiotic Theory | This is a set of membrane-bound regions, which consists of the nuclear envelope, the rough
and smooth endoplasmic reticulum, Golgi apparatus, and lysosomes. |
Eukaryotic Cells Part 1 Animal Cells and Endosymbiotic Theory | The rough endoplasmic reticulum is a network of membranes that enclose the ER lumen, which
is the stuff inside, consisting of sacs called cisterni. |
Eukaryotic Cells Part 1 Animal Cells and Endosymbiotic Theory | It's called the rough endoplasmic reticulum because its surface is studded with ribosomes,
giving it a rough appearance. |
Eukaryotic Cells Part 1 Animal Cells and Endosymbiotic Theory | These ribosomes synthesize polypeptides that are inserted directly into the ER lumen, where
they are typically folded and modified by enzymes in the ER membrane, and sometimes affixed
with a carbohydrate to make glycoproteins. |
Eukaryotic Cells Part 1 Animal Cells and Endosymbiotic Theory | These are often intended for secretion from the cell, so they gather into a vesicle, which
is like a bubble that buds from the ER membrane and then makes its way to the cell membrane,
thus releasing its contents to the extracellular space. |
Eukaryotic Cells Part 1 Animal Cells and Endosymbiotic Theory | The rough ER also synthesizes phospholipids that can be delivered to other parts of the
endomembrane system, and it takes proteins synthesized by the ribosomes that will be
cell membrane proteins, embeds them in its own membrane, and then delivers them via similar
transport vesicles. |
Eukaryotic Cells Part 1 Animal Cells and Endosymbiotic Theory | The rough ER is connected to the smooth ER, which is different in that it is not studded
with ribosomes. |
Eukaryotic Cells Part 1 Animal Cells and Endosymbiotic Theory | It also has a wider variety of functions, like synthesis, metabolism, and storage of
calcium ions to be used for signaling. |
Eukaryotic Cells Part 1 Animal Cells and Endosymbiotic Theory | The smooth ER produces phospholipids and steroids, like sex hormones. |
Eukaryotic Cells Part 1 Animal Cells and Endosymbiotic Theory | Vesicles in the smooth ER can detoxify drugs and poisons by adding hydroxyl groups to enhance
water solubility, and flush them from the body. |
Eukaryotic Cells Part 1 Animal Cells and Endosymbiotic Theory | Next in the endomembrane system is the Golgi apparatus. |
Subsets and Splits