proteins Flashcards
What are enzymes?
They are proteins which act as biological catalysts and speed up reactions.
What are proteins polymers of?
Amino acid joined together.
What do all amino acid molecules contain?
A central carbon with an amine group (-NH₂) and a carboxyl group (-COOH) as well as an R group which is variable organic group.
What are essential amino acids?
They cannot be synthesised in the human body and must therefore be consumed in our diets.
What holds forms such as spirals and sheets within a protein?
The amino acid chains are held in these forms by intermolecular bonding between amino acid side chains.
Why do proteins denature?
When they are heated, the intermolecular bonds between amino acids are broken, causing proteins to change shape (denature).
What causes the texture of food to change when we cook it?
It is the denaturing of proteins in foods when heated that cause the cooked texture to be different.
What type of reaction links amino acids together?
Condensation reactions.
The amine group of one amino acid and the carboxyl group on a neighbouring amino acid join together with the elimination of water.
What kind of link forms between amino acids?
An amide or peptide link
How are polypeptides broke down into amino acids?
Through hydrolysis.
How are proteins hydrolysed into amino acids in the lab?
By refluxing with hydrochloric acid.
How can amino acids be identified after acid reflux?
Through paper (thin layer) chromatography.
The distance travelled by a substance during chromatography depends on:
- polarity of the substance and the solvent
- the molecular weight (GFM) of the substance
- the polarity of the “solid phase” (chromatography paper)
