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Introduction to carbohydrates

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A carbohydrate is a type of molecule that contains carbon, hydrogen, and oxygen. Carbohydrates can be simple sugars (monosaccharides) like glucose, or they can be made up of multiple sugar units (polysaccharides) like glycogen. They are important in biology as a source of energy and as structural components in plants.

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  • female robot grace style avatar for user Ting Yi Chew
    Since glucose is the building block for glycogen, is starch and glycogen the same thing?
    (9 votes)
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    • orange juice squid orange style avatar for user Lily
      They are very similar to one another, however they aren't exactly the same thing. Both are not just linear chains of glucose molecules, but they are branched. Glycogen is more extensively branched than starch and it's also more compact. Also, starch occurs in plants and glycogen in animals.
      (23 votes)
  • leaf blue style avatar for user Sarah
    I've seen some new elements replacing the old ones:
    1. Uut = Ununtrium - Nh = Nihonium
    2. Uuq = Ununquadium - Fl = Flerovium
    3. Uup = Ununpentium - Mc = Moscovium
    4. Uuh = Ununhexium - Lv = Liverium
    5. Uus = Ununseptium - Ts = Tennessine
    6. Uuo = Ununoctium - Og = Oganesson
    What are these unknown elements and how did they come about?
    (10 votes)
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    • aqualine ultimate style avatar for user Russell
      These are all lab-created elements that are not known to appear in nature. Most of these have the "Unun" prefix name when they are first discovered and do not have an official name yet, but are eventually given actual names, often crediting the finder in some way.
      (8 votes)
  • leaf blue style avatar for user Prakrati
    Wait so what is the difference between a polymer and a polysaccharide?
    And monomer and monosaccharide?
    Or do they both mean the same thing?
    (7 votes)
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    • aqualine ultimate style avatar for user You
      Hello awesomeblue4. The answer to your third question is no they may sound and seem to have the same word but they are completely different meanings and properties as well. I have listed them below.

      What is the difference between a polymer and a polysaccharide?

      A polymer is a substance composed of molecules with large molecular mass composed of repeating structural units, or monomers, connected by covalent chemical bonds. While a polysaccharide is a polymer made up of many monosaccharides joined together by glycosidic linkages. They are therefore very large, often branched, molecules. They tend to be amorphous and insoluble in water

      What is the difference between monomer and monosaccharide?

      A monomer, simply, is the general term for anything that is the building block of something larger(polymers). But monosaccharides are an example of a monomer.

      Hope this helps
      Alphy :)
      (9 votes)
  • piceratops ultimate style avatar for user Leonardo Padro
    Is sugar made completely out of glucose or is there other stuff in there and if sugar is made completely out of glucose why do they have to process the sugar cane plant to make sugar?
    (7 votes)
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  • aqualine ultimate style avatar for user Jasmine Roush
    What does it mean when you say we're made out of Carbon atoms ?
    (3 votes)
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    • stelly yellow style avatar for user ⭐BEST20042007⭐
      Hi Jasmine! When Sal said we are made up of Carbon atoms, he means that most of our body mass is mostly carbon. For example, carbon atoms are in our hair, skin, and all of our cells are made up of large amounts of carbon. For a clearer picture, carbon makes up 18.5% of our body mass. That's alot if you think about it.

      Furthermore, if you want to know the reason why carbon takes up 18.5% of our body mass, I'll explain. Carbon atoms are unique because they have the ability to form bonds with up to 4 other atoms at the same time (simultaneously). As a result, this lets carbon atoms form long chains of molecules to serve as a base for life. Some examples include DNA and other proteins.

      I hope this helped!
      (5 votes)
  • blobby green style avatar for user Colton  Johns
    What is the energy process of biomolecule?
    (3 votes)
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    • stelly yellow style avatar for user ⭐BEST20042007⭐
      The energy process of biomolecules is basically a chemical process. The chemical energy that is already stored in molecules gets transformed into mechanical energy that will be used for cellular proccessing.

      Some examples of stored chemical energy in biomolecules are Carbohydrates and RNA/DNA.

      These are some of the cellular proccesses included: establishing the biochemical reactions (which use hormones), transmitting some genetic codes (RNA/DNA), and/or changing biological and neurological actions (neurotransmitter/hormones).

      Overall, I hoped this answered your question and helped!
      (2 votes)
  • blobby green style avatar for user ophkg88
    How about disaccharides? Do monosaccharides acts as a direct "building block" for disaccharides?
    (2 votes)
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  • male robot donald style avatar for user ESDRASV
    What exactly are Monosaccharides and polysaccharides?
    (1 vote)
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    • leafers ultimate style avatar for user Caleb H.
      Monosaccharides are the basic, small sugar molecules. Glucose and fructose are the ones you're probably most familiar with - each of these is a simple molecule with six carbon atoms.

      Polysaccharides are when you take a bunch of monosaccharides and chain them all together. Starch (like in a potato) is an example of this; it's just a bunch of glucose monosaccharides that have been linked together in a chain. This makes them easy to store, but they take slightly longer to digest.
      (5 votes)
  • blobby green style avatar for user Talya Göknar
    Why does some forms of glucose occur specifically in plants or bugs? For example why can we found chitin stored in the shells of bugs whereas we can't find it in plants?
    And also I couldn't understand why carbohydrates are used for energy in the first place. I mean why does the body prioritise the use of energy by using carbohydrates in the first place? for example why cant it use proteins?
    (2 votes)
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    • winston baby style avatar for user Ivana - Science trainee
      1. You should ask Mother Nature. That is the beauty of biodiversity, different physiology, different polymers.
      Bugs have to have very tough carapax, that's why chitin has to be incorporated. Based on modifications and chemical bonds it is tough.

      2. Carbohydrates are used as the primary source of energy for two reasons:
      1. the breakdown of their bonds releases lots of energy (that's what is most important) and
      2. they are very fast broken down (much faster than fats or proteins).
      (2 votes)
  • aqualine ultimate style avatar for user Miss Rayne
    I can't seem to find where Sal tells us what carbohydrates and glucose have to do with each other. Is glucose a type of carbohydrate? someone please help!
    (1 vote)
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    • blobby green style avatar for user thuthu
      Yes! glucose is just a type of carbohydrate.
      Carbohydrate literally means molecules containing carbon and water. (or maybe you can say carbon, hydrogen and oxygen)
      And there are many examples of carbohydrate apart from glucose, like fructose, sucrose or maltose....
      (3 votes)

Video transcript

- [Instructor] What we're going to do in this video is give ourselves a quick introduction to carbohydrates, and you might already be familiar with the notion. If you look at some packaged food, there's usually a nutritional label and will say carbohydrates. It will tell you a certain number of grams per serving. And not all carbohydrates are edible, but many of the things that we eat or many carbohydrates are edible and many of the foods we eat have some carbohydrate component to it. But what is it actually? Well, we can look at the word and we see carbo, so maybe it has something to do with carbons. And it says hydrates, so maybe it has something to do with water. And if you said that, you'd be pretty close because carbohydrates do involve carbons. In fact, this is a very typical carbohydrate, a very simple one right over here. This is a glucose molecule. And in gray, you see that it has six carbons. And the hydrate part refers to, that carbohydrates typically have oxygen to hydrogens in the same ratio as you would expect in water. So, for every one oxygen, two hydrogens, and you see that right over here, where in glucose, you have one, two, three, four, five, six oxygens and you have 12 hydrogens, and so that's where this word comes from. Now, another word that is often used interchangeably with carbohydrates is the term saccharide. Saccharide, and saccharide comes from Greek for sweet, and that makes sense because if you were to taste glucose, it would taste sweet to you. Now, what's interesting about something like glucose is glucose can be a standalone molecule, a very simple sugar in this case or you can build up larger molecules with really glucose as a building block. So for example, right over here, we have a part of a glycogen molecule. And as you can see, it's just a repeating sequence of glucose molecules. And so, something like this, we would call glucose a monosaccharide. It's one simple sugar right over here. Monosaccharide. And we would call this glycogen a polysaccharide. Polysaccharide. Or another way to think about it is glucose is the building block for the glycogen. Another term you might see is monomer and polymer. Those are the general terms or if I'm building a large molecule out of a chain of smaller ones, the building blocks, we consider to be monomers, and then the thing that we build out of those monomers could be our polymer. And as we'll see, this monomer polymer phenomenon is not limited to carbohydrates or saccharides. We're gonna see that same relationship, for example, between amino acids and proteins. Now, what role do carbohydrates play inside of biological systems? Well, saccharides or carbohydrates are often associated with the source energy. Glucose can be converted very quickly to energy in biological cells. Glycogen is also a store of energy in your liver and your muscles. And once again, it can be broken down into the glucose molecules, which once again, is a very readily available source of energy. Now, in plants especially, some of these polysaccharides could also play a structural role if we're talking about things like cellulose, which is another polysaccharide. So, there's also a structural role. Now, I will leave you there. We have focused only on one type of monosaccharide in glucose, and only on one type of polysaccharide in glycogen. As we will see, glucose does show up a lot but there are many other types of monosaccharides and there are many other types of polysaccharides. And polysaccharides in particular are part of a broader group of molecules known as macromolecules. And as you can imagine, from the macro prefix, it's referring to large molecules, oftentimes that have thousands of atoms in them. But don't get the wrong idea. They're very large at an atomic level but each of these circles are still atoms, so you would still need a very, very, very, very powerful microscope to even to take a look at even some of the largest macromolecules, including polysaccharides.