Organic Chemistry Chapter 10: Nitrogen and Phosphorus-Containing Compounds Flashcards Preview

MCAT Gen Chem and O Chem > Organic Chemistry Chapter 10: Nitrogen and Phosphorus-Containing Compounds > Flashcards

Flashcards in Organic Chemistry Chapter 10: Nitrogen and Phosphorus-Containing Compounds Deck (23)
1

The a-carbon of an amino acid is attached to

an amino group
a carboxyl group
a hydrogen atom
a R group

2

All amino acids are chiral, except

glycine

3

All amino acids in eukaryotes are L or D?

L

4

What is the only amino acid that does not have S stereochemistry?

cysteine - R

5

Amphoteric

they can act as acids or bases -- amino acids

6

Zwitterions

dipolar ions

7

Nonpolar nonaromatic amino acids

alanine, valine, leucine, isoleucine, isoleucine, glycine, proline and methionine _ tend to be hydrophobic

8

Aromatic amino acids

tryptophan, phenylalanine, tyrosine _ tend to be hydrophobic

9

Polar amino acids

serine, threonine, asparagine, glutamine and cysteine _ tend to be hydrophilic

10

Negatively charged amino acids

contain carboxylic acids in their R groups and include aspartic acid and glutamic acid _ tend to be hydrophilic

11

Positively charged amino acids

contain amines in the R groups and include arginine, lysine and histidine _ tend to be hydrophilic

12

Peptide bonds form by _ and can be cleaved by __

Formed by condensation -- cleaved by hydrolytically

13

What is needed to cleave a peptide bond?

strong acid or base

14

What restricts motion about the C-N bond in a peptide bond?

resonance of the peptide bond

15

Polypeptides

Strings of amino acids

16

What are two ways to synthesize amino acids in the lab?

Stecker synthesis - from an aldehyde
Gabriel synthesis - from potassium phthalimide, diethyl bromomalonate and an alkyl halide

17

Strecker synthesis

1. Aldehyde is mixed with ammonium chloride and potassium cyanide. The ammonia attacks the carbonyl carbon, generating and imine.
2. Imine is then attacked by the cyanide, generating an aminonitrile.
3. Aminonitrile is hydrolyzed by two equivalents of water, generating an amino acid.

18

Gabriel Synthesis

1. Phthalimide attacks the diethyl bromomalonate, generating a phthalimalonic ester
2. The phthalimidolmalonic ester attacks an alkyl halide, adding an alkyl group to the ester
3. The product is hydrolyzed, creating phthalic acid (with two carboxyl groups) and converting the esters into carboxylic acids.
4. One carbozylic acid of the resulting 1,3-dicarbonyl is removed by decarboxylation

19

Phosphorus is found in

Inorganix phosphate, a buffered mixture of hydrogen phosphate and dihydrogen phosphate

20

What is the bond in the backbone of DNA? What is released when it forms

Phosphodiester bonds - pyrophosphate is released

21

Why are phosphate bonds high energy?

large negative charges in adjacent phosphate groups and resonance stabilization of phosphates.

22

Organic phosphates

are carbon-containing compounds that also have phosphate groups. The most noteable examples are ATP and DNA

23

Why can phosphoric acid act as a buffer over a large range of pH values?

it has three hydrogens, each with a different pKa