Chapter 10- Nitrogen and Phosphorus Containing Compounds

Question 1

what type of reaction forms peptides

Answer 1

condensation reactions. when a bond is created between 2 nucleotide triphosphates in DNA synthesis the small molecule released from the reaction is pyrophosphate.

Question 2

which amino acids are optically active

Answer 2

all of them except for glycine because the functional group is just one hydrogen.

*note: amino acids are all amphoteric molecules and can act as both an acid and a base

Question 3

name the only amino acid with an R configuration and explain why

Answer 3

cysteine due to the change in priority caused by the sulfur in its R group

Question 4

what is the configuration of all amino acids (besides 1)

Answer 4

all of them are S except for cysteine

Question 5

what catalyzes the hydrolysis of a polypeptide

Answer 5

strong acid or base

Question 6

strecker synthesis

Answer 6

aldehyde + ammonium chloride + potassium cyanide (and water) —-> aminonitrile —> amino acid

-condensation then nucelophilic addition then hydrolysis

Question 7

gabriel (malonic-ester) synthesis

Answer 7

amino acid is generated from phthalimide and diethyl bromomalonate,

using Sn2 reactions, hydrolysis, and decarboxylation (loss of CO2 is the last step)

Question 8

similarities between strecker and gabriel synthesis

Answer 8

both result in racemic mixture of amino acids (L and D-amino acids b/c they start with planar molecules)

Question 9

phosphoric acid

Answer 9

• phosphate group (aka. inorganic phosphate)
• forms the high-energy bonds that carry energy in ATP
• excellent buffer b/c it has three hydrogens with pKa values that span nearly the entire pH scale.
• also found in DNA backbone and ATP/GTP but these ones are known as organic phosphates

Question 10

at physiological pH, which two forms of phosphoric acid have the highest concentrations?

Answer 10

H2PO4- and HPO4 2-