Biomolecules and Amino Acids Flashcards L 2

Flashcards covering key vocabulary from the lecture on biomolecules, enzymes, and amino acids.

Biomolecules

Molecules of all shapes and sizes involved in biology.

Intermolecular Interactions (Examples)

Electrostatic interactions, hydrogen bonding, Van der Waals forces, and the hydrophobic effect.

Amino Acid

A molecule containing both an acid group (carboxylic acid) and an amino group.

Alpha Amino Acid

An amino acid where the amino group (NH2) and carboxylic acid group (CO2H) are separated by a single (alpha) carbon.

R-group (in amino acids)

A substituent on the central carbon of an amino acid that determines its properties (polar, nonpolar, basic, or acidic).

Essential Amino Acids

Amino acids that cannot be synthesized by animals and must be obtained from their diet (e.g., arginine, histidine, lysine, threonine, methionine, isoleucine, valine, phenylalanine, and tryptophan).

Primary Amine

An amine with one R group attached to the nitrogen.

Secondary Amine

An amine with two R groups attached to the nitrogen.

Tertiary Amine

An amine with three R groups attached to the nitrogen.

Nucleophile

A species that is attracted to a positive charge or nucleus; the amine group acts as a nucleophile.

Amide

A compound formed by the nucleophilic attack of an amine on a carbonyl group.

Protonation (of Amines)

The process where amines react with acids, accept a proton, become positively charged, and form an ammonium ion.

Amphoteric

A substance that can behave as both an acid and a base (e.g., water).

pKa

A measure of acidity; the negative base-10 logarithm of the acid dissociation constant (Ka).

Chiral

A molecule that is non-superimposable on its mirror image, leading to enantiomers.

Enantiomers

Mirror image forms of a chiral molecule.

R/S Configuration

A system for assigning stereochemical configurations to chiral molecules based on the Cahn-Ingold-Prelog priority rules.

Hydrophobic Groups

Nonpolar side groups in amino acids (e.g., alkyl groups like methyl, propyl, butyl) that tend to avoid water.

Polar Side Groups

Side groups containing -OH or amide groups.

Zwitterionic Form

A form of an amino acid where it exists as a dipolar ion with both a positive (amino group) and negative (carboxyl group) charge.