Pearson+ LogoPearson+ Logo
Start typing, then use the up and down arrows to select an option from the list.


Learn the toughest concepts covered in biology with step-by-step video tutorials and practice problems by world-class tutors

11. Translation



Play a video:
Was this helpful?
Hi in this video we're gonna be talking about proteins. So translation has created some proteins and we're not going to spend a ton of time talking about proteins in this course because it's a genetics course and we don't really care as much about them other biology courses but I do want to briefly go over some of them. So proteins are made up of amino acids and they're organized into these chains called polyp peptide chains. Now there are four structural levels of proteins that you need to be aware of. It's called primary, secondary tertiary co ordinary. And that makes sense. So 1234. Now, primary structure refers to just the amino acid sequence. Secondary structure is local structures found within the poly peptide chains of things close to each other. And these can be divided into two structures which I'm going to show you a picture of to differentiate them. But these are alpha and beta sheets and they actually physically look different. Then you have tertiary structure And that is going to be the three D structure of the entire polyp peptide chain. And you have co ordinary structure which is the three D structure of multi polyp peptide chains that can make up a single protein. So proteins can be composed of lots of pollen peptide chains and co ordinary structure deals with that structure. Now, every single protein has an amino in and a car box cell in um So I like to think of this as kind of the start and this is the end. Um but it just is based on the amino group and the car box a group. So here we have primary structure. You can just see these are different amino acids and that is the sequence of them. Secondary structure is here and you have alpha helix sees which you can see is actually looks like a helix and you have beta sheets. This is an anti parallel. There's two types not super important, you know about them in this class but I'm gonna mention them here, that's not spelled at all correctly. This is anti parallel because the directions of the beta sheets are going opposite but it could be parallel if they were going the same in either direction. But this is a beta sheet that's anti parallel. And so this is a local or a regional sub structure that happens in the polyp peptide chain. The tertiary structure deals with the entire polyp peptide chain. So you can see there's a lot of beta policies here or beta sheets, there's a couple of alpha helix is here but this is the entire polyp peptide chain and what its structure looks like. And then you have to ordinary structure. Um so this is various polyp peptide chain. So here we have they're all in different colors. So we have the red one, the orange one, the green one and the blue one. So there's four polyp peptide chains here and each of them come together and their entire structure together makes up the co ordinary structure. Now if we talk about the individual amino acids themselves, we like to focus on the R group and the R group provides is the region of the amino acid that provides the proteins with certain properties. So our our groups can be non polar polar charge, negative, positive or negative. And um these are groups allow for the protein to fold into a bunch of different shapes. And proteins, shapes are divided into two main classes, even though there's a ton of different protein shapes. But we sort of divide them all into two classes. You have globular proteins. These are more compact proteins. So if this was a protein it would look like this and or something similar. And you have fibrous proteins which are linear proteins. So they just look like a line. It might be a squiggle line, but essentially it's just a line Three decline because these are three D. Things. Our groups also allow proteins that have specific domains which are structural regions that have specific functions. A good example of this are enzymes and they have active sites and these active sites sometimes could be domains these structural regions with specific functions. And protein folding is really controlled proteins mainly can fold on their own. But sometimes they need help And the proteins that help them are called chaperones and they help fold proteins correctly. So here is an example of chemical structure of what an amino acid looks like you have your carbon. You have your amino group that could spell you have your car box cell group Over here, you have a hydrogen. But the important group here is the R group and this gives different amino acids, certain properties, and when multiple amino acids are attached on here, each with different R groups that gives an entire polyp peptide chain, certain properties that help it fold and give it function and give it structure and all sorts of things. So that's a very brief overview of proteins. But this is a genetics class. So that's probably all you're gonna get. So with that, let's now move on.

Which of the following protein structures describes a 3D structure of one polypeptide chain?


Which of the following describes the amino acid sequence of a polypeptide chain?


Which of the following describes the 3D structure of multiple polypeptide chains in a single protein?


Which of the following describes the local structures formed in a single polypeptide chain?