Amino Acids (Class and Character)

Question 1

What are non polar nonaromatic amino acids?

Answer 1

Amino acids with hydrophobic side chains (avoid water)

Question 2

What is the structure of an amino acid?

Answer 2

An alpha carbon attached to an amino, carboxyl, and R group

Question 3

What are the 4 groups of amino acids?

Answer 3

• nonpolar and nonaromatic
• aromatic
• polar + uncharged
• charged amino acids (acidic and basic)

Question 4

What is an R group?

Answer 4

The amino acid’s side chain

Question 5

What determines the identity of an amino acid?

Answer 5

The R group

Question 6

What does aliphatic mean?

Answer 6

Non-aromatic

Question 7

What does hydrophobic mean?

Answer 7

That it can’t form H-bonds with water (non polar)

Question 8

What does hydrophilic mean?

Answer 8

That it can form H-bonds with water

Question 9

What is a non polar nonaromatic amino acid?

Answer 9

An amino acid with a hydrophobic R group that avoids water

Question 10

How do non polar non aromatic amino acids influence protein structures?

Answer 10

They increase the overall stability

Question 11

How do non polar non aromatic amino acids stabilize the protein structure?

Answer 11

By aligning their R group towards the interior of the protein molecule

Question 12

What is a unique characteristic of glycine?

Answer 12

It is able to provide flexibility to the protein’s structure

Can fit into tight turns of proteins

Question 13

What is a special characteristic of methionine?

Answer 13

Because it has a sulfur group, it can be (and often is) involved in initiating protein synthesis

Question 14

What is a special characteristic of proline?

Answer 14

It’s ‘R’ group is bonded to the amino group in the amino acid’s backbone

Question 15

How does a proline amino acid affect a protein’s structure?

Answer 15

Restricts flexibility and initiates β turns

Question 16

Why is proline often found in turns/twist of proteins?

Answer 16

Because the side chain is bound to the amino group, it helps initiate turns

Question 17

What are aromatic amino acids?

Answer 17

Amino acids with aromatic rings in their side chains

Question 18

How do aromatic amino acids influence protein structures?

Answer 18

They can increase UV light absorbance

Because they have a higher number of continuously conjugated carbons

Question 19

What is/are the non polar aromatic amino acid(s)?

Answer 19

Tryptophan and phenylalanine

Question 20

What is/are the polar aromatic amino acid(s)?

Answer 20

Tyrosine

Question 21

What is an important application of tyrosine?

Answer 21

It’s role in signaling pathways (that have tyrosine kinase receptors)

Question 22

What is the largest amino acid?

Answer 22

Tryptophan

Question 23

What is an important application of tryptophan?

Answer 23

It’s role in interactions proteins

Question 24

What are polar uncharged amino acids?

Answer 24

Amino acids with hydrophilic side chains

Question 25

What amino acids are involved in phosphorylation?

Answer 25

The amino acids that have an alcohol group ## Footnote (serine, threonine, and tyrosine)

Question 26

What is a unique characteristic of cysteine?

Answer 26

It's ability to easily form disulfide bonds with its thiol group

Question 27

What is an important application of cysteine?

Answer 27

It can increase protein stability

Question 28

How does cysteine stabilize the protein structure?

Answer 28

By forming disulfide bonds

Question 29

What is a common application of asparagine and glutamine?

Answer 29

Hydrogen bonding

Question 30

What are the two types of charged amino acids?

Answer 30

Acidic and basic

Question 31

What are the important applications of charged amino acids?

Answer 31

Protein stability and enzymatic activity

Question 32

How do charged amino acids help stabilize protein structures?

Answer 32

By creating electrostatic interactions

Question 33

What type of amino acids are involved in the active site of enzymes?

Answer 33

Histidine and acidic amino acids

Question 34

What is the charge on acidic amino acids?

Answer 34

Negative

Question 35

What is the charge on basic amino acids?

Answer 35

Positive

Question 36

What type of molecules does lysine normally bond to?

Answer 36

Negatively charged

Question 37

What is an important application of arginine?

Answer 37

Protein binding ## Footnote Because of its guanidinium group

Question 38

What is a unique characteristic of arginine?

Answer 38

It has a guanidinium group (which is highly basic)

Question 39

What is a unique characteristic of histidine?

Answer 39

It has an imidazole ring which can shuttle protons

Question 40

What are (2) important applications of histidine?

Answer 40

It's role in enzyme active sites and buffering

Question 41

What is an essential amino acid?

Answer 41

An amino acid that humans can't make and need to include in their diet

Question 42

What is a nonessential amino acid?

Answer 42

An amino acid that the human body can synthesize

Question 43

What does PTM stand for?

Answer 43

Post-translational modification

Question 44

What is a post-translational modification?

Answer 44

A chemical change made to a protein after its synthesis (in the ribosome)

Question 45

What are the four common types of amino acid PTM changes?

Answer 45

It's function, localization, and interactions?

Question 46

What are the four types of amino acids PTMs?

Answer 46

- Phosphorylation - Glycosylation - Acetylation/methylation - Ubiquitination

Question 47

What is phosphorylation?

Answer 47

Addition of a phosphate group

Question 48

What is a common application of phosphorylation (as a PTM)?

Answer 48

It's role in signaling pathways

Question 49

What is glycosylation?

Answer 49

Attachment of carbohydrate groups

Question 50

What are the effects on a protein of amino acid glycosylation (PTM)?

Answer 50

Changes in protein folding, stability, and cell recognition

Question 51

What is acetylation/methylation?

Answer 51

Modifications that usually occur on lysine residues

Question 52

What are the effects on a protein of amino acid acetylation/methylation (PTM)?

Answer 52

Influences gene expression and protein function

Question 53

What is ubiquitination?

Answer 53

Attachment of ubiquitin to lysine residues

Question 54

What is the effect on a protein of amino acid ubiquitination (PTM)?

Answer 54

It tags the proteins for degradation