peptides and proteins

Question 1

what are amino acids?

Answer 1

building blocks for proteins (20 amino acidosis types)

• biological macromolecules with specific functions
• contain at least 1 amino (-NH2) and carboxylic group (-COOH)

Question 2

structure of amino acids

Answer 2

• amino group
• carboxylic acid group
• hydrogen
• fourth group (side chain) that determines the amino acid diversity (H or complex organic group)
  
  • gives hydrophobic/hydrophilic properties

Question 3

what are zwitterionic molecules?

Answer 3

overall neutral but presents positive and negative charges in focused areas
- at certain pH a certain form will be favoured and found more in solution according to acidity

Question 4

protein structure

Answer 4

amino and carboxylic acid of 2 aminos react to form amide -> peptide bond

• chain can be extended indefinitely
• chain different according to nature and order of amino acids
• chain has polarity
• direction of chain is from amino group to carboxylic group (N->C)
• peptide bond: poorly reactive, can be hydrolysed, but the reaction with water is slow

Question 5

what are peptides?

Answer 5

peptides: polymer of amino acids (polypeptide: many amino acids)
- can be cyclic - free amino can react with carboxylate to form cyclic structure
- two peptides containing the cysteine (-CH2SH side chain, a thiol) can be linked via disulfide bonds