Amino Acids and phosphates

Question 1

Phosphates

Answer 1

Phosphoric acid is H3PO4 and contains a phosphate group PO43-

Question 2

Phosphates

In acid-base reactions

Answer 2

Phosphoric acid is a very good buffer in reactions due to three H, each with different pKa.

Question 3

Phosphates

Phosphodiester bonds

Answer 3

Phosphodiester bonds link together nucleotides in DNA.

Question 4

Phosphates

Phosphodiester bond formation

Answer 4

Phosphodiester bond formation is catalyzed by DNA ligase and releases a pyrophosphate product.

Question 5

Amino Acid

Structure

Answer 5

Has an α-carbon attached to four other groups:
1) amino group
2) carboxyl group
3) H atom
4) R group

Question 6

Amino Acid

Properties

Answer 6

Amino acids are amphoteric, meaning can be either an acid or a base.
At a certain pH range, they exist as dipolar ions called zwitterions

Question 7

Amino Acid

Peptide bonds

Answer 7

Links between amino acids. They have partial double bond character due to resonance among the C, N, O. Rotation around the bond axis is restricted.

Question 8

Amino Acid

Peptide bond formation

Answer 8

Peptide bonds are formed when the N-terminus of an amino acid performs a nucleophilic attack on the C-terminus of another amino acid.

Question 9

Amino Acid

Peptide bond cleavage

Answer 9

Peptide bonds are cleaved in a hydrolysis reaction, catalyzed by protease enzymes (ie trypsin).

Question 10

Amino Acid Synthesis

In vitro synthesis

Answer 10

Two methods of synthesizing amino acids in vitro: Strecker and Gabriel synthesis
1) Strecker synthesis: Generates amino acid from aldehyde
2) Gabriel synthesis: Generates amino acid from potassium phthalimide

Question 11

Amino Acid Synthesis

Strecker synthesis

Answer 11

Makes amino acids starting from aldehyde plus KCN and NH4Cl

Question 12

Amino Acid Synthesis

Gabriel synthesis

Answer 12

Makes amino acids starting from potassium phthalimide
Potassium phthalimide acts as a nucleophile in a Sn2 reaction