L1 Amino acids

Question 1

What is the central dogma of Biology?

Answer 1

DNA makes RNA and RNA makes proteins.

Question 2

How does DNA go to RNA?

Answer 2

DNA goes to RNA via the process of transcription.

Question 3

How does RNA go to Protein?

Answer 3

RNA goes to protein via the process of translation.

Messenger RNA carries coded info to ribosomes during protein synthesis.

Question 4

What is the basic structure of an amino acid?

Answer 4

Amino group, carboxylate group, hydrogen, alpha carbon and R group.
Groups covalently attached to tetrahedral alpha carbon

Question 5

Describe the general structure of an amino acid.

Answer 5

Tetrahedral structure.

Question 6

How do amino acids differ? By what group?

Answer 6

Amino acids differ by the R group that is attached to them. Each amino acid has a different R group.

Question 7

Why are amino acids categorized as zwitterions?

Answer 7

They act as either an acid or base.

Question 8

Describe amino acids in relation to chirality?

Answer 8

Amino acids have a tetrahedral alpha carbon bonded to four different chemical groups

Question 9

Which amino acid doesn’t display chirality?

Answer 9

Glycine

R group is hydrogen

Question 10

How are amino acids classified or group?

Answer 10

According the physiochemical properties of their R-group

Question 11

What is polarity defined as?

Answer 11

Polarity is defined as the magnitude of the dipole induced in the presence of an external electromagnetic field

Question 12

What are the four classifications of amino acids?

Answer 12

1. Polar
2. Non-polar
3. Positively charged
4. Negatively charged

Question 13

Name the non polar amino acids. (9)

Answer 13

Alanine
Valine
Leucine
Isoleucine
Phenylalanine
Tryptophan
Glycine
Methionine
Proline

Question 14

Name the polar uncharged amino acids. (6)

Answer 14

Threonine
Serine
Cysteine
Glutamine
Asparagine
Tyrosine

Question 15

What type of R groups do polar uncharged amino acids have?

Answer 15

hydroxyl
thiol
carboxyamide

Question 16

Which three polar uncharged amino acids are often involved in enzymatic reactions?

Answer 16

Threonine
Serine
Cysteine

Question 17

What type of R groups do non polar amino acids have?

Answer 17

Nonpolar R groups (aliphatic and aromatic with hydrophobic properties)

R group is a hydrocarbon

Question 18

What are the sulfur containing amino acids?

Functions?

Answer 18

cysteine- disulfide bridges

methionine- first a.a. when building a protein

Question 19

What are the polar charged amino acids? (5)

Answer 19

Arginine
lysine
Glutamate
Aspartate
Histidine

Question 20

What type of R groups do polar charged amino acids have?

Answer 20

carboxylate

amine

Question 21

What charge do amines have?

Answer 21

Neutral or positive

Question 22

What charge do carboxylates have?

Answer 22

Neutral or negative

Question 23

What are free amino acids?

Answer 23

Free amino acids have 2 or more acid/base groups and produce complex acid/base titration curves.

Question 24

What is an isoelectric point?

Answer 24

Isoelectric point is the pH at which the total charge of the amino acid and peptide or protein is zero.

Question 25

What is the isoelectric point for amino acids without ionizable R groups?

Answer 25

The PI is the average of the pkas

Question 26

What is the isoelectric point for amino acids with ionizable R groups?

Answer 26

The average of the pka of the amino acids on either side of species that has net charge of 0.

Question 27

What are peptide bonds? What does it involve?

Answer 27

Peptide bond is formed via a condensation reaction. It is a covalent bond formed between the carboxyl end of one amino acid residue and the amino end of another amino acid residue.

Question 28

Describe the direction of amino acid sequences.

Answer 28

Start at amino end and end at carboxylate

Question 29

What are the characteristics of peptide bonds? (4)

Answer 29

1. Partial double bond character 2. Rigid and planar 3. Trans configuration 4. Uncharged but polar