What Causes an Egg to Harden when Boiled?

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In summary, amino acids on their own do not have a specific function, but when they come together and form a protein, they can take on a particular structural or functional role in the cell. Boiling an egg causes it to harden because the heat causes the proteins within the egg to denature and bond together, creating a solid structure. To dissolve the hard boiled white, both a detergent and a reducing agent are needed because the proteins are held together by both hydrophobic and disulfide bonds, which can be broken down by these substances.
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what is the difference between amino acids on their own and amino acids that have been incorporated into a polypeptide chain?

My answer is that amino acids on their on do nothing. However when they interact they create a protein which eventually takes on a particular function.

why does boiling an egg cause it to harden?
why does it require both a detergent and a reducing agent to dissolve the hard boiled white.

Thanks
 
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Hey there! It's been a while since I've had Biology but I'm pretty sure you're thinking in the right direction. I haven't read anywhere that amino acids do anything else except bond to each other and produce proteins which have either structural or functional purposes. On their own, they're drifters just kind of floating around in the cell until they are ready to be used. This is about all I can explain right now...not sure what you mean by your last couple of questions. Do they have to do with amino acids in particular or the proteins formed by them? :rolleyes:
 
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for your question!

The hardening of an egg when boiled is due to the denaturation of proteins in the egg white. Proteins are made up of long chains of amino acids, which are held together by weak bonds. When heat is applied, these weak bonds are disrupted and the protein molecules unfold, causing the protein to change shape and become more firm. This is why the egg white changes from a clear, runny liquid to a solid, opaque substance when boiled.

As for the difference between amino acids on their own and those incorporated into a polypeptide chain, amino acids on their own do not have a specific function. However, when they are linked together in a specific sequence to form a polypeptide chain, they create a unique 3-dimensional structure that allows the protein to carry out its specific function. This structure is essential for the protein's proper functioning and can be affected by external factors such as heat, pH, and chemicals.

In regards to dissolving a hard-boiled egg white, both a detergent and a reducing agent are needed. The egg white contains a protein called avidin, which binds to biotin (a B vitamin) and makes it unavailable for absorption. Detergents are able to break down the lipid membrane surrounding the egg white, allowing the reducing agent to access the avidin and break it down. The reducing agent then breaks the disulfide bonds in the protein, causing it to unfold and lose its structure, making it easier to dissolve in water. Without both the detergent and reducing agent, it would be difficult to break down the protein and dissolve the hard boiled egg white.
 

Related to What Causes an Egg to Harden when Boiled?

What Causes an Egg to Harden when Boiled?

When an egg is boiled, the egg white and yolk become firm, or "hardened". This is a result of several chemical reactions that occur when the egg is exposed to heat and water.

1. Why does boiling an egg cause it to harden?

When an egg is boiled, the heat causes the proteins in the egg white and yolk to denature, or unfold. This causes the proteins to coagulate, or form a network of bonds, resulting in a firmer texture.

2. Does the temperature of the water affect how quickly an egg hardens?

Yes, the temperature of the water does affect how quickly an egg hardens. The higher the temperature, the faster the egg will cook and harden. However, boiling an egg at too high of a temperature can result in a rubbery texture.

3. Why does an egg white become opaque when boiled?

When an egg white is raw, it appears translucent. However, when heated, the proteins in the egg white coagulate and form a solid, resulting in an opaque appearance.

4. Can you prevent an egg from hardening when boiled?

No, the chemical reactions that occur when an egg is exposed to heat and water are necessary for it to cook and become firm. However, the length of time an egg is boiled can affect the texture, so adjusting the cooking time can result in a softer or firmer egg.

5. Is it safe to eat a boiled egg that has a greenish ring around the yolk?

Yes, a greenish ring around the yolk of a boiled egg is caused by a reaction between sulfur in the egg white and iron in the yolk. It is safe to eat, but it may result in a slightly rubbery texture and a slightly off flavor.

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