# Dehydration Synthesis and Hydrolysis ## Метаданные - **Канал:** Amoeba Sisters - **YouTube:** https://www.youtube.com/watch?v=ALFE2tNIY5c - **Дата:** 01.05.2026 - **Длительность:** 6:08 - **Просмотры:** 10,701 ## Описание Explore dehydration reaction (dehydration synthesis) and hydrolysis with the Amoeba Sisters! This video will introduce what these reactions are, how they work, and why they matter to organisms. Table of Contents: 00:00 Intro 0:42 Defining Dehydration Synthesis 1:30 Example in Proteins 2:54 Example in Carbohydrates 4:18 Hydrolysis 5:00 Why do these processes matter? --------------------------------------- FACTUAL REFERENCES: Clark, Mary Ann, et al. “Proteins - Biology 2e - OpenStax.” Openstax.org, 28 Mar. 2018, openstax.org/books/biology-2e. Urry, Lisa A, et al. Campbell Biology. 11th ed., New York, NY, Pearson Education, Inc, 2017. --------------------------------------- FURTHER RECOMMENDED READING: 🔎 We mention the need for an investment of energy for dehydration synthesis and that often this tends to involve coupling with other reactions. Want to learn more? Here's a reading suggestion: check out the section about how the hydrolysis of ATP can drive energetically unfavorable reactions: https://ecampusontario.pressbooks.pub/bioc2580/chapter/atp-as-cellular-energy-currency/ ----------------------------------------------- The Amoeba Sisters videos demystify science with humor and relevance. The videos center on Pinky's certification and experience in teaching biology at the high school level. 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TRANSLATIONS: https://www.amoebasisters.com/pinkys-ed-tech-favorites/community-contributed-subtitles ## Содержание ### [0:00](https://www.youtube.com/watch?v=ALFE2tNIY5c) Intro [intro music] Note: Captions are on. You know, when we talk about biomolecules,  we talk a lot about monomers. And polymers.    Monomers are the building blocks that are  often repeated and can form a polymer.    For example - with proteins - monomers can be  amino acids. The polymer can be a polypeptide. But you know a question that  used to keep me up at night?    How do the monomers stick together? Like  how do amino acids join together to make a   giant polypeptide? How do monosaccharides  join together to form a polysaccharide? And then… I learned about…dehydration synthesis!   Also can be called dehydration reaction. You know, ### [0:42](https://www.youtube.com/watch?v=ALFE2tNIY5c&t=42s) Defining Dehydration Synthesis the word dehydration often makes me think of  not having enough water. Being dehydrated.    Dehydration synthesis will involve losing water.    And synthesis, if you remember, means  to make something. So, basically,   you’re making something and losing water to do  it. Dehydration synthesis is a chemical reaction   that, with some exceptions, joins many types  of monomers together. Let’s get into it! We’ll start with the monomers of proteins,  amino acids. We know we usually draw amino   acids like this, but, let’s get a little  more fancy! Let’s draw them showing the   general elements in their structure. Remember  we mentioned a popular mnemonic to remember   major elements in biomolecules - using that  - you should expect elements like carbon, ### [1:30](https://www.youtube.com/watch?v=ALFE2tNIY5c&t=90s) Example in Proteins hydrogen, oxygen, and nitrogen to be found  in proteins and in their amino acid monomers. And you’d be right. Here is one amino  acid with its elements. On the left side,   this is an amino group. Notice the nitrogen,  the hydrogens. Here is a central carbon,   also called an alpha carbon! And attached to  this central carbon is a hydrogen and an R group.    Sometimes called a side chain. R groups can vary  depending on the particular amino acid - there’s   quite a few amino acids to choose from after all.   Now, let’s look at this on the right side of our   illustration. It’s a carboxyl group! It’s got  a carbon and oxygen double bonded here - that’s   a carbonyl- and it’s got an OH, the OH is  hydroxyl. Whole thing is a carboxyl! You know,   just a side note looking at this, the word  “amino acid” might make more sense now because   you see it’s got an amino group and a carboxyl  group, a carboxyl being acidic, so amino acid. Dehydration synthesis means that the hydroxyl (OH)  of one of the amino acids on the carboxyl side,   and a hydrogen (H) on the other amino acid on  its amino side combine. Water, H2O, is released.    A covalent bond between the amino acids is formed,  and in proteins, this is known as a peptide bond. Let’s do another example. Carbohydrates now. ### [2:54](https://www.youtube.com/watch?v=ALFE2tNIY5c&t=174s) Example in Carbohydrates We like to draw general monomers of  carbohydrates, called monosaccharides,   like this. But let’s get more fancy here, let’s  draw them showing the elements in their structure.    If you remember the popular mnemonic for  biomolecules, you would expect carbon,   hydrogen, and oxygen in carbohydrates  and also monosaccharides, their monomers. And you’d be right. Here is the monosaccharide,  glucose. Beautiful ring structure.    Here’s another monosaccharide, fructose.   Put them together and you get sucrose.    This can form from a dehydration reaction. A  hydroxyl (OH) from one of the monosaccharides   (we’ll show it coming from glucose) combines  with hydrogen (H) from the other monosaccharide   (we’ll show it coming from fructose) and water  is released. A covalent bond forms between these   two monosaccharides, specifically, the bond is  known as a glycosidic linkage or glycosidic bond. So both of those showed dehydration synthesis  joining these monomers together. But we feel   there’s a little bit of an elephant in the room  and that is - how did it happen, how’d it start? Generally, this requires an investment of energy,  and reactions are usually coupled with other   cellular processes to make it happen. You can  explore some details with that in our description.    And to speed up the reaction, cells often  have the help of enzymes or molecules that   act like enzymes. Enzymes can also assist  in making sure monomers are in position. One last thing. What you make - in  this case - you can break. Sure, ### [4:18](https://www.youtube.com/watch?v=ALFE2tNIY5c&t=258s) Hydrolysis dehydration synthesis might join monomers to  make polymers but you can break them down again.    The chemical reaction that breaks the bonds  between monomers is called hydrolysis.    Like its name would suggest  with “hydro” - it needs water. Take our example with the carbohydrate  monomers that had been bonded together   in dehydration synthesis. If a water molecule  (H2O) is inserted in this bond that holds these   monosaccharides - specifically, in this glycosidic  bond - you will notice that this monosaccharide   gets a hydrogen and the other gets a hydroxyl.   Enzymes often play a role in hydrolysis, too.    This particular example could  involve the enzyme sucrase. So we went through dehydration synthesis and  hydrolysis and you might wonder: why does this ### [5:00](https://www.youtube.com/watch?v=ALFE2tNIY5c&t=300s) Why do these processes matter? matter? Well, biomolecules like carbohydrates and  proteins, perform essential functions for living   organisms. And the different forms that many  biomolecules take are critical for their function.    Dehydration synthesis is involved for many,  though not all, of these larger polymer forms.    And as for breaking them down? In order for  organisms to survive, they are breaking down   biomolecules - for example, take the human  digestive system. Hydrolysis breaks down most   biomolecules - breaking these down in digestion  into smaller components that can be absorbed   and used by the body. Explore all the diverse  biomolecule functions in our biomolecules video. Well, that’s it for the Amoeba Sisters,  and we remind you to stay curious! --- *Источник: https://ekstraktznaniy.ru/video/50408*