Proteins Amino Acids

Proteins are made up of a combination of how many unique amino acids?

• 10

• 20

• 25

• 50

What is the basic structure of an Amino acid?

• basic group, aliphatic group, hydrogen and a R side chain

• acidic group, amino group, hydrogen and a R side chain

• positively charged group, acidic group, hydrogen and an aromatic group

• negatively charged group, basic group, hydrogen and an aliphatic group

How many essential amino acids are there?

• 3

• 9

• 12

• 20

Simplest amino acid that is optically not active (has no stereo- isomers)

• Glycine

• Serine

• Isoleucine

• Glutamine

The chirality of an amino acid results from the fact that its a carbon that:

• has no net charge

• is a carboxylic acid

• is bonded to 4 different chemical groups

• is symmetric

Amino acids are ampholytes because they can function as either a(an):

• acid or base

• neutral molecule or an ion

• polar or non polar molecule

• positive or negatively charged

In a neutral solution, most amino acids exist as:

• positively charged compounds

• zwitterion molecules

• negatively charged compounds

• hydrohobic molecules

The central carbon of an amino acid is called?

• alpha carbon

• beta carbon

• chiral carbon

• asymmetric carbon

Which of the following statements is most likely to be true of non-polar R groups in aqueous solution?

• They are hydrophillic and found buried within proteins

• They are hydrophillic and found on protein surfaces

• They are hydrophobic and found within proteins

• They are hydrophobic and found on protein surfaces

Two amino acids that contain sulfur atoms are:

• cysteine and serine

• cysteine and threonine

• methionine and cysteine

• methionine and serine