amino acids

• What are proteins?


  Biomolecules made of monomeric units (amino acids) linearly. bound to each other by peptidic bond
• Why are amino acids useful monomers?

  Capacity to polymerize

  varied physical properties

  varied chemical functionality

  useful acid base properties
• What is the structure of an amino acid?


  An amino group and a carboxyl group bound to the same carbon , weak basic and acidic group with a R chain

  
• What are the characteristics of the alpha carbon?

  C alpha has 4 substituents , length and angle of four bonds are similar , tetrahedral shape , asymmetric (chiral centre)
• In what form are amino acids found?

  L enantiomers
• What are the five groups of amino acids?

  Non polar/aliphatic , aromatic , polar uncharged , positively charged , negatively charged
• What are the non polar amino acids?

  Glycine , alanine , proline , valine , leucine , isoleucine , methionine
• What does glycine look like?

  
• What does alanine look like?

  
• What does proline look like?

  
• What does valine look like?

  
• What does leucine look like?

  
• What does isoleucine look like?

  
• What does methionine look like?

  
• What are the aromatic amino acids?

  phenylalanine, tyrosine, tryptophan
• What does phenylalanine look like?

  
• What does tyrosine look like?

  
• What does tryptophan look like?

  
• What are the polar uncharged amino acids?

  serine, threonine, cysteine, asparagine, glutamine
• What are the characteristics of the polar uncharged amino acids?

  Polar side chains can form hydrogen bonds , cysteine can form disulfide bonds with another cysteine
• What does serine look like?

  
• What does threonine look like?

  
• What does cysteine look like?

  
• What does asparagine look like?

  
• What does glutamine look like?

  
• What are the negatively charged amino acids?

  aspartate, glutamate
• What are the characteristics of the negatively charged amino acids?

  Amino acids side chains can form ionic bonds
• What does aspartate look like?

  
• What does glutamate look like?

  
• What are the positively charged amino acids?

  lysine, arginine, histidine
• What are the characteristics of the positively charged amino acids?

  Amino acids side chains can form ionic bonds
• What does lysine look like?

  
• What does arginine look like?

  
• What does histidine look like?

  
• What are the acid base properties of the amino acids?

  Amino is a weak basic group , carboxyl is a weak acidic , some amino acids have additional groups that can get ionized
• What is the Henderson-Hasselbalch equation?

  pH = pKa + log [A-]/[HA]
• How do amino acids exist at low ph?

  All groups are protonated (+1 charge)

  
• How do amino acids exist at neutral ph?

  carboxyl group is deprotonated but amino group is protonated (zwitterion)

  
• How do amino acid exist at high ph?

  Amino group is neutral and acidic group remains ionized (-1 charge)

  
• What does pk1 and pk2 mean?


  Pk1 - pka of carboxyl of amino acid

  Pk2 - pka of amino of amino acid

  pk1<pk2