Compare and contrast the characteristics of fibrous and globular proteins. Consider biological function, water solubility, amino acid composition, secondary structure, and tertiary structure. Give examples of three fibrous and three globular proteins. (Hint: Make a table.)

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Hello, everybody. Let's take a look at our next problem. It says, consider the partially filled table that includes the water solubility, biological function, amino acid composition, secondary structure and tertiary structure of globular and fibrous proteins. Choose the set that correctly fills the table. So these characteristics that we talked about are are rows and then we have two columns, globular and fibrous. And there are some blank spaces in our table. Six of them numbered one through six. And then we have answer choices A through D with options for filling in numbers one through six. So let's look over our table and think about these blank spaces and then we'll match it with our answer choices. So our first row water solubility is both are filled in globular says mostly soluble fibrous says mostly insoluble. Our next row is biological function. But we're going to skip that for a moment and drop down to amino acid composition because that we can intuit from our solubility. So under globular, we have its blank and it's number two, while fibrous says, acids with small non reactive side groups, let's see what our options are for. Number two, describing globular proteins and amino acid composition. Well, in choice, a number two says hydrophilic groups on the outside. Well, does this make sense? Yes, because to be soluble, you'd want hydrophilic groups on the outside of your globular or globe shaped globular protein to be interacting with your aqueous environment, hydrophobic groups on the outside that will result in an insoluble protein. So that would be a correct answer for. Number two choice B says hydrophilic groups on the inside. Well, you wouldn't expect this to be the answer. So they're not going to help you tucked in the inside of the protein, you want them out interacting with that environment. So we'll rule out choice B since its answer for number two is incorrect. So I see for number two says hydrophilic groups on the outside. So that's a correct answer for number two. And then choice D says number two hydrophilic groups on the inside. So again, that's going to be incorrect and rule out choice D. So these were down to two answer choices. So now let's back up here up to our second row of biological function. So for globular proteins, this says enzymes, hormones and transport. Now we have fibrous proteins. Well, why are they called fibrous because they have these long fiber like chains that make them up. And so what kind of function would that lead us to? Let's look at our answer choices. So this is labeled number one because remember we skipped that row. So for choice A, it's the number one structural. Well, that would be correct. If we have long fiber like chains that's going to fulfill a structural function, then our other choice. So C is the other one we haven't ruled out. That also says structural. Just for curiosity's sake. What did B and D say? Well, they had messenger as number one so that we wouldn't expect that to be correct. So we've done one and two. Let's move on to the next row. And number three back this row has two blank spaces for three and four. So that's for secondary structure. A reminder that secondary structure means the presence of alpha helices or beta sheets. So we're talking about interactions between the backbones of the amino acid or, or of the peptide chain. And what are our choices? So answer choice. A for number three, for globular says smaller parts of alpha helix or beta sheet. And for number four, fibrous says large parts of alpha helix or beta sheet. Well, this makes sense globular proteins and their globe like structure have a lot of folds. So you couldn't have big long runs of a long alpha helix or long beta sheets as that would prevent its ability to fold. Whereas long fiber like chains might well have long runs of this secondary structure. So that makes sense for three and four. Let's check choice C it says number three smaller parts of alpha helix or beta sheet. And for choice four or for space four large parts of alpha helix or beta sheet. So that's correct. Then we move on to an extra which is tertiary structure. Well, that's both filled in. We don't have to figure anything out says for globular depends on the type of side chains and disulfide bonds. And for fibrous few interactions between side chains on the same backbone. And now our last row two blank spaces is examples of these proteins labeled five and six. So let's recall when we think about examples of type of protein. Let's recall that globular proteins are going to be functional for enz there'll be enzymes, they will be hormones, they will transport things, they'll do things, you know activities while fibrous proteins, we decided were structural proteins. So let's look at choice. A for globular examples. Number five, it has collagen, Mycin and Elastin. Well, hopefully these guys jump out to you as structural proteins. So that is going to be incorrect for number six, they have Hemoglobin Amily syndrome bisco, these are functional. Well, they're all functional. But do you know what? You know what I mean? They do things, we put activities. So that's going to be incorrect as well. So that rules out choice A by elimination. We have choice. C let's double check our examples on this. Number five says hemoglobin amylase R bisco. So it's just the reverse of A and that makes sense. Hemoglobin carries oxygen, we know that amylase is a digestive enzyme. An enzyme hemoglobin is involved in transport. And then RBI is an enzyme of the Calvin cycle. So that is correct. And then it has four, number six collagen mycin and elastin, which are structural proteins. So we have our answers to correctly fill in this table. It's in choice C, that's the set that fills it in. Number one structural. Number two hydrophilic groups on the outside. Number three, smaller parts of alpha helix are beta sheet. Number four, large parts of alpha helix are beta sheet. Number five, hemoglobin, amily ribis, number six collagen Myo Elastin, hope to see you in the next video.

Compare and contrast the characteristics of fibrous and globular proteins. Consider biological function, water solubility, amino acid composition, secondary structure, and tertiary structure. Give examples of three fibrous and three globular proteins. (Hint: Make a table.)

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Key Concepts

Fibrous Proteins

Globular Proteins

Protein Structure