Chapter 1: Amino Acids, Peptides, and Proteins

Question 1

what are the basic animo acids?

Answer 1

lysine, arginine and histidine

Question 2

nonpolar, nonaromatic side chains

Answer 2

alanine, valine, leucine and isoleucine

they all have alkyl side chains

Question 2

aromatic side chains

Answer 2

tryptophan, phenylalanine and tyrosine

Question 3

polar side chain

Answer 3

serine, thronine, aspqragine, glutamine and cysteine

Question 4

negatively charged (acidic) side chains

Answer 4

aspartic acid (aspartate) and glutamic acid (glutamate)

Question 5

positively acid (basic) side chains

Answer 5

lysine, histidine and arginine

Question 6

hydrophobic amino acids

Answer 6

alanine, isoleucine, leucine, valine and phenylalanine

Question 7

hydrophilic amino acids

Answer 7

histidine, arginine, lysine, glutamate and asparagine

Question 8

acidic vs basic conditions

Answer 8

at very acidic pH values, amino acids tend to be positively charged. At very alkaline pH values, amino avids tend to be negatively charged

Question 8

isoelectric point

Answer 8

the pH at which the molecule is electrically neutral.

pI = pKa (base) + pKa(acid) / 2

Question 9

peptide bond formation

Answer 9

called condensation reaction, happens when the electroplhilic carbon on the first amino acid is attacked by the nucleophilic amino group on the second amino acid. It produces water.

Question 9

charged pI

Answer 9

amino acids with acidic chains have pI values well below 6; and amino acids with basic side chain have pI values well above 6.

Question 9

how are alpha helix stabilized?

Answer 9

hydrigen bonding

Question 10

keratin

Answer 10

the apls=helix is a important component in its structure

Question 11

disulfine bonds

Answer 11

the bonds that form when two cysteine molecules become oxidized to form cystine

Question 12

cooperativity

Answer 12

one subunit can undergo conformational changes which can either enchance or reduce the activity of the other subunits.

Question 13

molten globule

Answer 13

intermediate state in protrein folding

Question 14

denaturation

Answer 14

can happen with heat or solute.

heat will overcome the hydrophobic interactions that hold proteins together, causing it to unfold

solute will interfere in the forces that hold protein together

Question 15

hydrophobic interactions in the reactions theormodynamic

Answer 15

the hydrophobic R group will be pushed to the interior of the protein by the hydrophobic interactions and then it increases entropy of the suppounding water molecules and reates a negative Gibbs free energy

Question 16

zwitterion

Answer 16

a pH near the pI of the amino acid, the amino acid is neutral

Question 17

hydrolysis

Answer 17

breaking peptide bonds

Question 17

acidic amino acids have a pI ____

Answer 17

well below 6

Question 18

basic amino acids have a pI ____

Answer 18

weell above 6

Question 19

gluatamate

Answer 19

glutamic acid

Question 19

aspartate

Answer 19

aspartic acid