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Large Biomolecules

In large biomolecules, such as polypeptides (proteins), multiple non-covalent interactions can occur between different parts of the same biomolecule to stabilize the structure.

Amino acids

Amino acids

  • Proteins are made of amino acids.
  • Amino acids consits of a carboxylic acid croup, an amine group, and a variable R group.
  • Neighboring amino acids are joined via peptide bonds between the amine and carboxylic acid group.
  • Interactions between R groups creates the complex 3D tertiary structure of a protein.
  • The 3D structure is usually coiled or folded.
Holding the 3D structure

Holding the 3D structure

  • There are many weak and strong interactions that determine the final 3D shape of the protein (e.g. ionic bonds and hydrogen bonds).
  • When the protein loses its 3D shape, it may no longer be functional.
    • This 3D structure is known as the tertiary structure of the protein.
Ionic bonds

Ionic bonds

  • Charged amino acids have a positively or negatively charged ion in their side chain.
    • Charged amino acids can form relatively strong ionic bonds with other charged amino acids.
  • Ionic bonds between amino acids are quite rare.
Hydrogen bonds

Hydrogen bonds

  • Hydrogen bonds also form between amino acids.
  • Hydrogen bonds are relatively weak but when there are many, the overall stability of the tertiary structure increases.
Hydrophobic interactions

Hydrophobic interactions

  • When protein folding takes place, the hydrophobic R groups of nonpolar amino acids lie in the interior of the protein, whereas the hydrophilic R groups lie on the outside.
    • These types of interactions are also known as hydrophobic interactions.
Jump to other topics
1

Structure - Models of the Particulate of Matter

2

Structure - Models of Bonding & Structure

3

Structure - Classification of Matter

3.1

The Periodic Table: Classification of Elements

3.2

Periodic Trends

3.3

Group 1 Alkali Metals

3.4

Halogens

3.5

Noble gases, group 18

3.6

Functional Groups: Classification of Organic

3.7

Functional Group Chemistry

3.8

Alkanes

3.9

Alcohols

3.10

Halogenoalkanes

4

Reactivity - What Drives Chemical Reaction?

5

Reactivity - How Much, How Fast & How Far?

6

Reactivity - The Mechanisms of Chemical Change

7

Measurement, Data Processing & Analysis

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