Chapter 4

Question 1

What are five amino acid derivatives, and what does each example do?

Answer 1

Glycine, GABA, and dopamine- neurotransmitters.
Histamines- mediator of allergic reactions.
Thyroxine- thyroid hormone that regulates metabolism.

Question 2

What amino acid was GABA synthesized from?

Answer 2

Glutamate/Glutamic acid

Question 3

What amino acid are histamines synthesized from?

Answer 3

Histidine

Question 4

What amino acid is thyroxine and dopamine synthesized from?

Answer 4

Tyrosine

Question 5

What is the isoelectric point (pI)?

Answer 5

The pH at which the net electric charge of an amino acid is zero.

Question 6

What is a peptide?

Answer 6

Two or more amino acids are covalently linked by peptide bonds.

Question 7

How are peptide bonds made?

Answer 7

Through a condensation reaction (removal of a water molecule).

Question 8

What is an oligopeptide?

Answer 8

A peptide whose molecules contain a relatively small number of amino acid residues.

Question 9

What is a polypeptide?

Answer 9

A linear organic polymer with a large number of amino acid residues bonded together in a chain, forming part of (or all of) a protein molecule.

Question 10

What are the amino-terminal and the carboxyl terminal of a protein?

Answer 10

Question 11

What does the amino acid sequence equal?

Answer 11

The protein function.

Question 12

What is a prosthetic group?

Answer 12

Non-amino acid chemical component of proteins usually plays an important role in protein’s functionality.

Question 13

What are lipoproteins?

Answer 13

Proteins that contain lipids.

Question 14

What are glycoproteins?

Answer 14

Proteins that contain sugars.

Question 15

What are metalloproteins?

Answer 15

Proteins that contain metal ions.

Question 16

What is green fluorescent protein?

Answer 16

Comes from bioluminescent jellyfish and is used in biotechnology (GFP tagging).

Question 17

What is glutathione?

Answer 17

Involved in tissue building and repair, making chemicals and proteins needed in the body, and in immune system function.

Question 18

What is a zwitterion?

Answer 18

When an amino acid lacking an ionizable “R” group is dissolved in water at neutral pH, it exists in a solution as the dipolar ion.

Question 19

How are disulfide bonds formed in amino acids?

Answer 19

The oxidation of two cysteines. Disulfide bonds stabilize the structures of many proteins.

Question 20

Which is the only amino acid that is not optically active?

Answer 20

Glycine.

Question 21

What do Fischer projections do?

Answer 21

Allow stereoisomers to be visualized.

Question 22

What configuration are all amino acids that are incorporated into proteins?

Answer 22

L-configuration (goes with S configuration).

Question 23

Which amino acid does not have a chiral center?

Answer 23

Glycine.

Question 23

What are the building blocks of nature and can be arranged in enumerable ways?

Answer 23

Proteins.

Question 24

What is the maximum light absorbance of W and Y?

Answer 24

280nm. Can help determine protein concentration values.

Question 25

What is an amino acid classified by?

Answer 25

Its “R” group.

Question 26

What are ampholytes?

Answer 26

Compounds that can behave as either an acid or a base and are amphoteric

Question 27

What does amphoteric mean?

Answer 27

Is able to react as both and acid and a base.