amino acids/ proteins

Draw glycine

What is its charge and polarity at ph7

Draw alanine

What is its charge and polarity at ph7

Draw serine

What is its charge and polarity at ph7

Draw tyrosine

What is its charge and polarity at ph7

Draw glutamic acid

What is its charge and polarity at ph7

Draw glutamine

What is its charge and polarity at ph7

Draw cysteine

What is its charge and polarity at ph7

Draw cysteine

What is its charge and polarity at ph7

Draw valine

What is its charge and polarity at ph7

Draw proline

What is its charge and polarity at ph7

draw leucine

What is its charge and polarity at ph7

Draw isoleucine

What is its charge and polarity at ph7

Draw methionine

What is its charge and polarity at ph7

Draw tryptophan

What is its charge and polarity at ph7

Draw phenylalanine

What is its charge and polarity at ph7

Draw arginine

What is its charge and polarity at ph7

Draw histidine

What is its charge and polarity at ph7

Draw threonine

What is its charge an polarity at ph7

Draw asparagine

What is its charge and polarity at ph7

Draw asparctic acid

What is its charge and polarity at ph7

• What letters used for isomers of amino acids

• Explain the type of isomerism they exhibit

D and L isomerisms

They are enantiomers/ exhibit optical isomerism (non superimposable mirror image) due to an asymmetrical central carbon

Which amino acid enantiomer is present in organisms

L isomer

How do polar charge pd side chains interact with water

• +charge: partial negative on the O in water attracted to + charge

• - charge: partial positive charge on the H attracted to -charge

• Hydrophilic

How do polar uncharge side chains interact with water

How are polar molecules considered uncharged

• Partial charges on the side chains can form hydrogen bonds with water

• Hydrophilic

• Overall neutral charge but have partial charge due to unequal distribution

How do non polar side chains interact with water

• Side chains Cant bond with water

• Hydrophobic

• Water forms an organised the side chains

  
  

Why are non polar side chains within the inside of the protein

• Cells are aqueous which non polar side chains hydrophobic to water

• Causes water to become more ordered

• - entropy so unfavourable

• So inside protein to reduce contact with water to increase entropy of the system

Unique properties of glycine

Side chain is one H so no L or D isomer

Makes tight turns In protein structure

Unique property of cysteine

Disulphide bridges

Unique property of proline

Join onto the a-amino group which creates a kink in the peptide backbone

Often found at turns

Prevents rotation about the bond between the nitrogen and alpha carbon reducing flexibility

Special properties of peptide bond

Shorter then expected bond length between c-n resembles Dble

Partial - on O partial + on N

Form H bonds with polar groups

Not rotation

Trans arrangement

Protein folding

Fold through rotation around the phi and psi bonds of a polypeptide chain

Creates restricted torsion angles

What is an alpha carbon

Central carbon in an amino acid

Which way are amino acids drawn

N terminus on left C terminus on right

What are residues

Some atoms lost from the amino acid when a peptide is formed during a condensation reaction

The remaining chemical unit inside the polypeptide is the residue

Special properties of peptide bonds

Shorter than expected c-n bond length similar to double bond

Form hydrogen bonds with other polar groups

Rigid C_N bond so no rotation

Trans arrangement of groups

What is torsion angles and what are their properties

Rotation Ii