Amino Acids, Peptides, and Proteins Flashcards Preview

Biochemistry > Amino Acids, Peptides, and Proteins > Flashcards

Flashcards in Amino Acids, Peptides, and Proteins Deck (20):
1

What is the general structure of amino acids, and what single amino acid is the exception?

Enantiomers Proline is the exception

2

What amino acids contain nonpolar, aliphatic R groups?

Glycine, alanine, proline, valine, leucine, isoleucine, methionine

3

What amino acids contain aromatic R groups?

Phenylalanine, tyrosine, tryptophan

4

What amino acids contain polar, uncharged R groups?

Serine, threonine, cysteine, asparagine, glutamine

5

What amino acids contain positively charged R groups?

Lysine, arginine, histidine

6

What amino acids contain negatively charged R groups?

Aspartate, glutamate

7

What is the only one of the aromatic amino acids with an ionizable side chain?

Tyrosine

8

What amino acid is responsible for most of the absorbance of ultraviolet light by proteins?

Tryptophan

9

What is the correlation of environmental pH on pKa?

As pH increases, pKa increases

10

In a titration curve, how do you calculate pI?

Take the first and second pKas and find the average

11

How are peptide bonds formed by condensation?

Two amino acids come together; one has a carboxy terminus and the other has an amino terminus. Loss of water allows the two amino acids to bond via a peptide bond.

12

Describe the planar peptide group

The carbonyl oxygen has a partial negative charge and the amide nitrogen has a partial positive charge, causing the molecule to have a dipole. This is a trans configuration

13

Characteristics of alpha-helix, cross linked by disulfide bonds

tough, insoluble protective structure of varying hardness and flexibility

14

Characteristics of beta conformation

Soft, flexible filaments

15

Characteristics of collagen triple helix

High tensile strength, without stretch

16

What is proteostasis?

process by which cells control the abundance and folding of the proteome

17

Name this uncommon amino acid

4-hydroxyproline

found in collagen

18

Name this uncommon amino acid

5-hydroxylysine

found in collagen

19

Name several ways that peptides differ from proteins

-peptides contain 50 or fewer amino acids

-peptides are generally smaller than proteins

20

In what organ does the production of most plasma proteins occur?

liver