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28 Dec 2025

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3 pages

Introduction to Amino Acids: Key Biological Molecules

sheila

@study_withsheila

Amino acids are the building blocks of proteins - essential... Show more

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amino acids
biological molecules
There are 20 different
amino acids
general structure
There are 3 main
parts to the amino
Structure
R
amine

The Basic Structure of Amino Acids

Every amino acid follows the same basic blueprint, making them surprisingly simple to understand. Picture a central carbon atom with three key parts attached: an amine group (containing nitrogen), a carboxyl group (the acidic bit), and most importantly, an R group that makes each amino acid unique.

Think of amino acids like LEGO blocks - they all have the same connecting pieces (amine and carboxyl groups) but different coloured tops (the R groups). There are exactly 20 different amino acids in nature, each with its own special R group that gives it unique properties.

💡 Quick Tip: The R group is what matters most - it determines whether an amino acid is hydrophobic, hydrophilic, acidic, or basic, which ultimately affects how proteins fold and function.

These biological molecules contain carbon, hydrogen, nitrogen, and oxygen as standard, with some also containing sulfur for extra chemical versatility.

Building Peptide Bonds

When amino acids meet, they don't just sit next to each other - they actually join up through a clever chemical reaction. The amine group of one amino acid bonds with the carboxyl group of another, forming a peptide bond and releasing a water molecule in the process.

This condensation reaction happens in your ribosomes every time your cells make proteins. Two amino acids joined together create a dipeptide, whilst three or more form a polypeptide chain.

💡 Remember: This reaction needs a specific enzyme to make it happen quickly enough for life - your body doesn't leave protein synthesis to chance!

The beauty of this system is its simplicity - the same basic reaction repeated thousands of times can build incredibly complex molecules from just 20 different amino acid building blocks.

Breaking Down Proteins

Just as amino acids can join together, peptide bonds can be broken apart when needed. This reverse process is called hydrolysis - literally meaning "splitting with water" - and it's exactly what happens when you digest proteins in your food.

Protease enzymes in your digestive system carry out this hydrolysis reaction, adding water molecules back to break peptide bonds and release individual amino acids. Your body can then recycle these amino acids to build new proteins.

Here's the crucial bit: a polypeptide isn't quite the same as a protein yet. The polypeptide chain needs to fold into a complex 3D shape before it becomes a functional protein that can actually do its job in your body.

💡 Key Point: The sequence of amino acids determines how the protein folds, and the folding determines the function - get the sequence wrong, and the protein won't work properly.

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28 Dec 2025

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3 pages

Introduction to Amino Acids: Key Biological Molecules

sheila

@study_withsheila

Amino acids are the building blocks of proteins - essential biological molecules that make up everything from your muscles to enzymes. Understanding how these simple structures link together to form complex proteins is crucial for grasping how life works at... Show more

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The Basic Structure of Amino Acids

💡 Quick Tip: The R group is what matters most - it determines whether an amino acid is hydrophobic, hydrophilic, acidic, or basic, which ultimately affects how proteins fold and function.

These biological molecules contain carbon, hydrogen, nitrogen, and oxygen as standard, with some also containing sulfur for extra chemical versatility.

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Access to all documents

Improve your grades

Join milions of students

By signing up you accept Terms of Service and Privacy Policy

Building Peptide Bonds

💡 Remember: This reaction needs a specific enzyme to make it happen quickly enough for life - your body doesn't leave protein synthesis to chance!

The beauty of this system is its simplicity - the same basic reaction repeated thousands of times can build incredibly complex molecules from just 20 different amino acid building blocks.

Sign up to see the contentIt's free!

Access to all documents

Improve your grades

Join milions of students

By signing up you accept Terms of Service and Privacy Policy

Breaking Down Proteins

💡 Key Point: The sequence of amino acids determines how the protein folds, and the folding determines the function - get the sequence wrong, and the protein won't work properly.