7. Prokaryotic Cell Structures & Functions
Was this helpful?
In this video, we're going to begin our lesson on pro carry attic ribosomes. And so a reboot zone is a cell structure that's found on the inside of all cells, regardless of what type of cell they are. And so these ribosomes consist of a large and a small ribbons, zonal sub unit. And so these large and small ribosomes will sub units will associate with each other to form the complete ribs. Um And that complete ribosomes will be able to perform protein synthesis or building proteins. And so ribosomes are also referred to as the site of protein synthesis. Now, although all cells have ribosomes, the ribosomes are not always going to be identical in different cells. And so pro carry attic ribosomes will be different from eukaryotic ribosomes and we'll be able to talk more about that as we move forward in our course. Now the large and small ribbon symbol sub units that come together to make up the full ribosomes. Those sub units actually consist of multiple proteins along with ribosomes RNA as well or are RNA for short. And so the ribosome itself is really just a big mixture of proteins and ribosomes RNA. And we'll be able to talk more about this idea as we move forward. Now in this uh set of videos were mainly going to be focusing on pro carry attic ribosomes. And so we'll talk about the pro carry attic ribosomes structure in our next video. So I'll see you all there.
Structure of Prokaryotic Ribosomes
Was this helpful?
in this video, we're going to talk more about the structure of pro carry attic ribosomes. And so in order to better understand the structure of pro carry out of ribs owns. Its first helpful to address what the sedimentation coefficient is. And so this sedimentation coefficient is measured in units called Svedberg units, named after the scientist that helped discover them. And the Svedberg units are abbreviated with the capital letter S. And so what you're going to see is that the ribosome will sub units. And the ribosomes themselves are basically named using this fed berg units. And so you'll see this s throughout this lesson. And so what is this sedimentation coefficient anyways? Well, it's a value that is going to characterize the rate of sedimentation and the particles behaviour. And an instrument known as a centrifuge, which is a laboratory instrument that spins really, really fast and is commonly used to help separate materials by using centrifugal forces. Now. Really, what you guys should know is that the greater the S Value is the spadework value, the faster the molecule will centrifuge. And so by labeling these rebels normal components with the S. Value, you can get a sense for the size of the sub unit. And so what's important to note here is that pro Kerry arctic organisms, they have what are known as 70 S. Rival zones. And so the 70 S. Is referring to the sedimentation coefficient for that ribosomes. And so these 70 S ribosomes are going to have to ribosomes sub units, a large ribosomes sub unit and a small ribbons normal sub unit. And so the large ribosomes sub unit is a 50 S. Large ribosomes sub unit And the small ribs almost sub unit is a 30 s. small ribosomes sub unit. And so the large 50 S. Ribs almost sub unit, and the small 30 S. Ribs almost sub unit, will come together to create the S ribosomes. And this is only going to be the case in pro carry arctic organisms and eukaryotic organisms. The ribosomes are different and we'll talk more about the eukaryotic ribosomes later in a different video in our course. But for now, one thing to note is that 50-plus 30 does not equal 70. And so a lot of times students have the tendency to try to simply add the Svedberg units, but that is not how they work. And so you cannot just simply add them instead. The 50 S. Large rivers, almost subunit when it complexes with the small 30 S. Rivers, almost subunit. Once again, it forms the 70 S ribosomes and we'll be able to see that down below in our image. Now the large 50 s. ribs, normal sub unit. Ah The large 50 S ribosome subunit actually is going to contain uh to ribbons. Um O. R. N. S. A. 23 S ribosomes, O. R. N. A. And a five S Ribas OMO RNA. And then the 30 s. Small ride is almost sub unit is going to have a s ribosomes RNA. And so we'll be able to see this down below in our image as well. And so in this image, what we're focusing on is the pro carry attic ribosome structure. And so this entire blue circle that you see right here is the ribosome of approach periodic sell. And so this is a 70 s ribs. Um when all of the components are together, Now notice that this uh 70 s ribosome consists of a large subunit and a small subunit. The large subunit is right here and the small subunit is down below right here. And so one thing to note is that the large sub unit is a S large subunit and the small subunit is a 30 s. small subunit. And so, um together when the 50 S large subunit uh combines with the 30 S. Small subunit, it forms the full 70 S rival zone. Now notice that within the large ribosome subunit there are two ribosomes, all our NHS that are highlighted here in yellow. And so if we go back up to the text, you can see that the 50 S large ribosome subunit has a 23 S and five S ribosomes are in it. And so this larger one here would be the 23 s ribosomes o. r. n. a. And the smaller one here would be the five S Ribas, Omo RNA. And then in the small ribbons almost subunit down below right here notice that there is also a ribosome O. R. N. A. Right here in yellow. And that is the 16 S ribosomes are in a Now one thing to note is that here in the middle there are three compartments uh right here, right here and right here and these three compartments are the active site of the rebel zone. And so we'll talk more about these three compartments later in our course, when we talk about the process of protein synthesis, specifically translation, we'll talk more about those later in our course. But one thing to also note is that Arcadia although they are pro carry outs along with bacteria, the ribosomes are not identical. The Rko and bacterial ribosomes are the same in size. So they are both 70 s ribosomes. But they are different in two important ways that we have numbered down below one and two. The first important way that our kale ribosomes are different from bacterial ribosomes is that the sequence of the ribosome A. R. N. S. Or the R. R. N. S. Are different. And so the 23 S are RNA, the five S. R. R. N. A. And the 16 S. R. R. N. A. All have different sequences in arcadia. And so that's why we have different sequences here in this image. To remind you that archaea have different sequences for those rivals normal R. N. S. In comparison to bacteria. Now, the second important way that our kale ribosomes differ from bacterial ribosomes is that Rko ribosomes have more proteins in each sub unit. And so to remind you of that we have here, this note that Arcadia have um sorry but that our care have more proteins than bacterial ribosomes. Rko ribosomes have more proteins than bacterial ribosomes. And so because our kale ribosomes are not identical to bacterial ribosomes, this is really the reason why Arcadia are unaffected. They are not affected by antibiotics that target protein synthesis of bacteria. And so once again, these ribosomes are important for protein synthesis. And so antibiotics that target ribosomes and bacteria may not work to target ribosomes and our cave since they have some differences. And so this year concludes our lesson on the structure of pro carry attic ribosomes, and once again, we'll be able to apply these concepts as we move forward in our course. So I'll see you all in our next video.
Which of the following statements about ribosomes is FALSE?
Ribosomes synthesize new lipids.
Ribosomes synthesize new proteins.
Ribosomes are made of protein.
Ribosomes are made of RNA.
Prokaryotic 70S ribosomes are composed of which of the following subunits?
40S and 40S
40S and 50S
30S and 50S
30S and 40S
50S and 50S
Svedbergs are a measurement of the size and sedimentation rate of cellular structures such as ribosomes.
How are prokaryotic and archaeal ribosomes different from one another?
Large and small subunits are different in size.
The sequences of rRNAs are different.
Archaeal ribosomes have less proteins per subunit than prokaryotes.
Archaeal ribosomes have more proteins per subunit than prokaryotes.
A and C
B and D
B and C