Proteins Flashcards
What are the monomers of proteins
Amino acids
What is the structure of an amino acid
1) a central carbon atom
2) to the right is the carboxyl group (COOH)
3) to the left is the amino group (NH2)
3) a hydrogen atom (H) off of the central C
4) R group on the other side of the C
How many common amino acids are there and how do they differ
20 and they differ in their R group
What do combined amino acids form
A dipeptide
Draw out a peptide bond on paper
Do it
What is polymerisation
When many amino acids join through condensation, it results in a polypeptide
Can a functional protein contain one or more polypeptides
Yes
The role of hydrogen bonds in the structure
Linked amino acids have NH and CO on either side of a peptide bond, the H is positive while the O is negative so hydrogen bonds are formed in the secondary structure which cause polypeptide to twist into a a helix
Role of ionic bonds and disulphide bridges in protein structure
All three bonds maintain the tertiary structure, ionic bonds are formed between any carboxyl and amino group not forming bonds (weak and easily broken by changes in pH), disulfide bridges which are strong and hydrogen (numerous but easily broken)
Describe the quarternary structure
More than 1 polypeptide chain with all the bonds (hydrogen, disulphides bridges, ionic bonds)
What is the biuret test for proteins
1) add equal volumes of sample and sodium hydroxide @ room temp
2) add drops of dilute copper sulfate and mix
3) purple means there’s peptide bonds, blue means none
Describe how a peptide bond is formed between two AA to form a dipeptide
Amino acid monomers joined in a condensation reaction to form a dipeptide. Water is made by combining an OH from carboxyl group and H from amino group and is taken out. Peptide bond formed between Carbon and Nitrogen between amino acids
What is the meaning of hydroxylating
Adding a hydroxyl group onto a molecule
What are the two types of molecule ribosomes are made from
Protein and ribosomal rna
