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

Microbiology

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

5. Molecules of Microbiology

Carbohydrates

1
concept

Carbohydrates

clock
4m
Play a video:
Was this helpful?
in this video, we're going to begin our lesson on carbo hydrates. Now. Carbohydrates can be defined as carbon based molecules that air hydrated with many hydroxy local groups, which recall are just a functional group that looked like this with an oxygen and hydrogen atom. And so when we take a look at our image down below of carbohydrates, one thing that you'll notice is that there are plenty of these hydroxyl groups throughout their structures, and so that is definitely a characteristic feature of carbohydrates. Now. Carbohydrates are also referred to as sacha rides, and so sacha rides is really the Greek word. That means sugars, and so sugars are carbohydrates. Now, when the term carbo hydrates was originally coined way back in the hundreds, it was actually referring to compounds that had the exact chemical formula of C. N. H. 20 N, where you had some number of carbon atoms being hydrated by some number of water molecules. And that's exactly where it got its name, from the carbo for the car buns and the hydro or the hydrates for the water molecules that air hydrating the carbon atoms. Now it turns out that simple carbohydrates are carbohydrates that fit this chemical formula exactly. For example, glucose is a carbohydrate that fits this chemical formula exactly, and glucose is three most abundant carbohydrate, and it's the one that you guys should all be familiar with, and we'll be able to see an example of glucose down below in our image. But not all carbohydrates fit this chemical formula. Exactly. And so there are some complex carbohydrates and complex carbohydrates are going to be carbohydrates that can slightly differ from this chemical formula here. And they can also have other types of atoms, such as phosphorus, nitrogen or sulfur atoms, to. So let's take a look at our example down below to distinguish between the simple and complex carbohydrates. So notice on the left hand side over here when we take a look at its chemical formula, and we count up the total number of carbon atoms, the total number of hydrogen atoms throughout and the total number of oxygen atoms throughout. What we'll see is that there are a total of six carbon atoms, a total of 12 hydrogen atoms and a total of six oxygen atoms. And so what you'll notice is that there are six water molecules that we can make out of the H 12 06 on those water molecules air hydrating, the six carbon atoms. And so this is going to be a molecule that fits the chemical formula up above. Exactly. And so this is going to be an example of a simple carbohydrate. More specifically, this is the chemical structure of glucose. And once again, glucose is the most abundant carbohydrate. And you should start to recognize its chemical formula of C six H 12 06 Because at some point in your course, you will need to know this chemical formula. Now, over here on the right hand side, what we're showing you is a complex carbohydrate, and we can tell that it's a complex carbohydrate because its chemical formula does not match the one that we have up above and so notice that it has a total of six carbon atoms. But when you count the hydrogen atoms, there are 11 of them. And when you count the oxygen atoms, they're actually nine of them. And there's also one phosphorus atom as well, which you can see up above right here. And so this is a complex carbohydrate, not because it has a circular shape, but because its chemical formula does not fit the one up above Exactly. And so moving forward were mainly gonna be focusing on simple carbohydrates. But it's good for you to also know that complex carbohydrates also do exist. And so this here concludes our introduction to carbohydrates. And we'll get to talk Mawr and Maura about carbohydrates as we move forward in our lessons. So I'll see you all in our next video.
2
Problem

Which of the following chemical formulas represents that of a simple carbohydrate?

a) C2H2O2.

b) C6H12O6.

c) C5H4O3.

d) C3H6O9.

3
concept

3 Size Classes of Carbohydrates

clock
3m
Play a video:
Was this helpful?
In this video, we're going to introduce three different size classes of carbohydrates that we have number down below, and the numbers here correspond with numbers that we have throughout our image. Now, which will notice is that for all three of these size classes, the words Sacha ride here is present, which recall from our last lesson. Video means sugar. And so Sacha Ride is present and all three of these size classes, which means sugar, and that's referring to carbo hydrates. And so, really, these three different size classes. They differ in the root word there prefix. And so the very first size class is going to be the mono sacha ride. Now recall that mono is a prefix that means just one or singular. And so mono sack rides are going to be a single carbo hydrate unit. Or, in other words, mono. Sacha rides are the monomers of carbo hydrates, and that is very, very important for you. All to note now an example of a mono sacha ride is glucose, which once again, is the most abundant mono sacha ride. And so it's one that you all should start to familiarize yourself with a little bit, okay? And so when we take a look at our image down below notice number one is the mono sacha, right? Which is just a single carbohydrate unit or just a single hexagon here, if you will. Now the second size class of carbohydrate is going to be the Allah go Sacha ride. And so Allah go is a prefix that means Ah phew. And so, Allah go Sacha ride when you put it together means a few sugar. So somewhere between two and 20 covertly linked mono sacha rides would be classified as Allah go Sacha rides. So when we take a look at our example down below at number two, the ahl ago Sacha rides we're showing you two types were showing you one here that has to sugar units linked together. So this would be more specifically a die sacha ride since dies a prefix meaning to And then here what we have is a try. Sacha ride since tries a prefix meaning three and there are three sugar units linked together. But once again, anywhere between 2 to 20 would be considered Allah go Sacha rides. And so these are some all ago sack rides here now, the third size class of carbohydrate that you all should be familiar with are the poly Sacha rides. And once again, Polly is a prefix that means many. And so these air going to have greater than 20 covertly linked mono Sacha rides together and Polly Sacha rides are, of course, going to be the polymer form of the carbohydrate. And so when we take a look at our image down below at the Poly sack rides here, notice that it has more than 20 covertly linked mono Sacha ride units together. And so we start to form the Poly sack. Right, Moving forward. We're going to talk about some specific examples of Polly Sacha rides and their functions. So keep that in mind. But for now, this year concludes our introduction to the three size classes of carbohydrates, mono Sacha rides, Allah go sack rides and Polly sack rats, and we'll be able to get some practice moving forward in our course. So I'll see you all in our next video
4
concept

Formation & Breakdown of Polysaccharides

clock
3m
Play a video:
Was this helpful?
in this video, we're going to talk about the formation and the breakdown of Polly Sack, arise and so recall from our previous lesson videos that dehydration synthesis reactions would be needed to link individual mono. Sacha rides together an order to build Polly Sacha rides. And so, once again, the synthesis part of dehydration lets us know that we're going to be building or synthesizing the poly Sacha rides. Now the co Vaillant bonds that link individual mono sacha rides together are going to be referred to as glycoprotein acidic bonds. And so Glick acidic bonds are once again the Covalin bonds that link mono. Sacha rides together and then last but not least, recall that the hydraulics, ISS reaction, eyes what's going to be needed to break down. So hydraulics is's used to break down Polly Sack rides into individual mono sack rides. So when we take a look at our image down below, we can see the formation of a sugar called maltose from two glucose molecules. So notice on the far left. Over here we have these two separate mono sack rides, one over here and one over here, and these are two separate glucose mono sacha rides. And so if we wanted to join these two separate glucose mono Sacha rides together like what we have over here, then we're going to need, of course, a dehydration synthesis reaction, which we know dehydrates the molecule releasing a water molecule. And also what forms is a co violent bond linking the two separate mono sack rides. And so when these two are linked together, the Covalin bond that links them is referred to as a glycol acidic bond, just like what we indicated up above. And so notice that as soon as these two glucose mono sacha rides are joined together, it becomes a new sugar that we call mall toes. And so this is a maltose die Sacha ride, starting to build power Polly Sacha right here. And so if we wanted to break down this Malta's Dice, aka right into its individual mono sack rides. And, of course, we're going to need the hydraulics, ISS reaction and recall licenses. That route that means breakdown or cleave. And so that's going to break down or cleave the Glick acidic bond here to release the two separate mano sack rides. And so, ah, lot of review here. But one of the main takeaways is once again that the bond between individual mono sack rides is referred to as a glycol acidic bond. So this here concludes our introduction to the formation and breakdown of Polly Sacha rides, and I'll see you all in our next video.
5
Problem

Monosaccharides are linked together via a ______________ reaction, forming a _____________bond.

a) Hydrolysis ; Glycosidic.

b) Dehydration synthesis ; Hydrogen.

c) Hydrolysis ; Peptide.

d) Dehydration synthesis ; Glycosidic.

e) Hydrolysis ; Hydrogen.

6
Problem

Which of the following chemical reactions results in energy release when glycosidic bonds are broken?

a) Condensation reaction.

b) Dehydration synthesis reaction.

c) Hydrolysis reaction.

d) Hydrogen bonding.

7
concept

Carbohydrate Functions

clock
5m
Play a video:
Was this helpful?
in this video, we're going to talk about carbohydrate functions. And so it turns out that carbohydrates are structurally and functionally diverse, meaning that they could do so many different things for the cell because they can take on so many different types of structures. However, that being said, really, there are just two main functions that you all should be aware of when it comes to carbohydrate functions, and so the first function that you all should be aware of is structural support. And so some carbohydrates are used specifically to build the structures of cells and the structures either within cells or on the outside of cells. For example, cellulose and chitin are two classic examples of some Polly sack rides that air used for structural support, and there are some others as well. For example, Petito go, I can might be one that you may or may not have heard of, but we're going to focus specifically on cellulose and chitin now, the second primary main function that you should know that carbohydrates have is energy storage, and so carbohydrates are specifically used for short term energy storage and so they can provide energy to living cells So, for example, starch and glycogen are both examples of carbohydrates that air used for short term energy storage. So let's take a look at our example down below to focus in on the poly. Sacha rides that air in plants and animals and the functions that they have. So notice that we have this, uh, image down below of this grid where the first column we have the function. Whether is structural support like this Bob the builder guy or energy storage like these batteries over here. And then we have the poly sacha rides that air found specifically in plants here in this, uh, column and the poly sacraments that have found specifically in animals over here in this column. And so notice that we're showing you to structural support, uh, carbohydrates, one in plants and one in animals. And we're also showing you to energy storage, uh, carbohydrates once again, one in plants and one and animals. So it's a nice little grid here. So when we're talking about structural support, a classic example of a poly sack right and plant that's used for structural support is cellulose, and so cellulose is actually the most abundant carbohydrate that's found in plant cell walls. And so when we take a look at plants like this leaf right here and we zoom in on its structure, which will notice is that the cell walls of these plants contain cellulose, and so it's used to build cell walls. And that's why it is structural support now, a structural support, uh, carbohydrate in animals, eyes going to be what we see over here, which is chitin and soak. Iten is a structural support carbohydrate that's found in the exo skeletons of insects and crustaceans such as lobsters. And so, if we were to zoom into the exoskeleton shell here of this lobster, we would see that Kite Newton would be found within its structure. And so kite structure is complex, and we don't really need to worry about its particular structure so much. Just knowing that Kitten is an example of a structural support carbohydrate that's used to build the structures of exoskeletons and then, in terms of energy storage, we're showing you tua's well over here. In plants, plants mainly store their energy in the form of starch, and so starch is going to be, uh, the storage form of glucose specifically in plants, and you'll find lots and lots of starch inside of potatoes like this one over here on then. Over here, what we have is an animal liver and in animals, uh, the They store their energy in the form of glycogen. And so glycogen is a poly sacha ride or carbohydrate whose main function is to store glucose in animal cells. And so this here concludes our introduction to carbohydrate functions, and we'll be able to get some practice applying these concepts in our next few videos, so I'll see you all there.
8
Problem

Animal cells store energy in the form of _________, and plant cells store energy in the form of ___________.

a) Sucrose ; glucose.

b) Disaccharides ; monosaccharides.

c) Starch ; glycogen.

d) Cellulose ; chitin.

e) Glycogen ; starch.

9
Problem

Which polysaccharide is an important component in the structure of lobsters and insects?

a) Chitin.

b) Cellulose.

c) Starch.

d) Glycogen.

e) Polypeptides.

Divider