Study Notes
Amino acids are organic compounds with both acidic and basic properties, capable of forming zwitterions and peptide bonds. They can be separated using techniques like electrophoresis based on their charge and size.
- Amino Acid Structure — Amino acids have a basic amino group and an acidic carboxylic acid group. Example: Glycine has the simplest structure with an R group as hydrogen.
- Amphoteric Nature — Amino acids can act as both acids and bases. Example: In water, they can donate or accept protons.
- Zwitterions — Molecules with both positive and negative charges. Example: At the isoelectric point, amino acids exist as zwitterions.
- Isoelectric Point — The pH at which an amino acid exists as a neutral zwitterion. Example: Glycine has an isoelectric point around pH 6.
- Peptide Bond Formation — A bond formed between the amino group of one amino acid and the carboxylic group of another. Example: Dipeptides are formed by two amino acids linked by a peptide bond.
- Electrophoresis — A technique to separate ions based on their movement in an electric field. Example: Amino acids can be separated by electrophoresis based on their charge and size.
Exam Tips
Key Definitions to Remember
- Amino Acid Structure
- Amphoteric Nature
- Zwitterions
- Isoelectric Point
- Peptide Bond Formation
- Electrophoresis
Common Confusions
- Confusing zwitterions with neutral molecules
- Misunderstanding the isoelectric point as the pH where amino acids are most reactive
Typical Exam Questions
- What is a zwitterion? A molecule with both positive and negative charges.
- How is a peptide bond formed? Through a condensation reaction between the amino group of one amino acid and the carboxylic group of another.
- What factors affect the rate of ion migration in electrophoresis? Size and charge of the ions.
What Examiners Usually Test
- Understanding of amino acid structure and properties
- Ability to explain peptide bond formation
- Application of electrophoresis in separating amino acids