Exam 1

Question 1

Which bonding forces involves the electrostatic attraction between two molecules with partial charges created by induced dipoles along bond axes? Or molecules in close proximity?

Answer 1

LDF

Question 2

Which of the sets of two amino acids below would represent a conservative
substitution if one were to replace another in a protein?

Answer 2

Find the amino acid pair that are both nonpolar, polar, or ionizable

Question 3

What is a common property of the side chains of the amino acids shown above?

Answer 3

Classify if they are all nonpolar, polar, or ionizable. If they’re all nonpolar, they can be buried inside of a protein structure

Question 4

What type of bond is formed between the side chains of two cysteine residues?

Answer 4

Covalent bond

Question 5

Micelle

Answer 5

Hydrophobic interior and hydrophilic exterior

Question 6

Which bonding force is most important for the localization of hydrocarbon side
chains when fatty acids are forming a micelle structure?

Answer 6

Hydrophobic interactions

Question 7

Which of the molecules below form bilayer structures when dispersed in water?

Answer 7

Phospholipids

Question 8

If temperature drops, a phospholipid membrane becomes too rigid. How can fluidity be achieved again?

Answer 8

Either decrease the amount of carbons or increase the amount of double bonds

Question 9

If temperature raises, a phospholipid becomes too fluid. How can rigidity be achieved again?

Answer 9

Either increase the amount of carbons or decrease the amount of double bonds

Question 10

Which amino acid when substituted for another amino acid in a reverse
turn would be most likely to result in a pathogenic mutation?

Answer 10

Tryptophan. Typically you want small side chain amino acids for reverse turns, such as glycine, alanine, and serine

Question 11

Which of the peptides below would segregate hydrophobic residues to a
single surface of an beta helical structure?

Answer 11

Find the amino acids that are NP, P, NP, P, NP, P this will create beta pleated sheets

Question 12

Which bonding force would form between the side chains of arginine and glutamic acid at pH 7?

Answer 12

Ionic bonds- the N+ from R and O- from Q will ionically bond

Question 13

Which amino acid begins the synthesis of proteins specified by the genetic code?

Answer 13

Met- codes for AUG which is the start codon

Question 14

Which amino acid replaces glutamic acid at position 6 of beta chains in sickle cell
disease?

Answer 14

Valine

Question 15

Which amino acid has an isoelectric point of 10?

Answer 15

Lysine. Must find an amino acid that has a pKa similar to the isoelectric point

Question 16

pKa of Histidine (His, H):

Answer 16

6

Question 17

pKa of Lysine (Lys, K):

Answer 17

10

Question 18

pKa of Tyrosine (Tyr, Y):

Answer 18

10

Question 19

Which interaction between functional groups of the polypeptide backbone plays a critical role in stabilizing alpha helices?

Answer 19

N-H and C=O

Question 20

Anfinsen’s experiment involving ribonuclease denatured with urea showed that…

Answer 20

Proteins are capable of folding into complex three-dimensional structures capable
of functioning properly solely through the interactions of a polypeptide chain with the
aqueous environment. Proteins, once denatured, are able to refold back into their original form.

Question 21

What is needed for a polypeptide chain to fold into its native three-dimensional structure?

Answer 21

Interaction with an aqueous environment

Question 22

What is inhibited by 5’-fluoracil?

Answer 22

Synthesis of dTMP

Question 23

What would be prevented by inhibiting the
the activity of tRNA synthetases?

Answer 23

Addition of amino acids to tRNA’s

Question 24

Translation is the biochemical process that results in the synthesis of?

Answer 24

Proteins, polypeptides, ubiquitin, etc

Question 25

T/F: A polypeptide is required to have a signal sequence in
order to enter the endoplasmic reticulum?

Answer 25

True

Question 26

A reason a protein may be trafficked to the mitochondria is?

Answer 26

It contains a mitochondrial localization signal

Question 27

Inhibition of which enzyme would block the synthesis of
ALL deoxyribonucleotides?

Answer 27

Ribonucleotide reductase

Question 28

Allopurinol is used to inhibit which enzyme?

Answer 28

Xanthine Oxidase (gout)

Question 29

Nucleosomes contain…

Answer 29

Histones H2A, H2B, H3, H4, which are rich in BASIC amino acids

Question 30

Which of the following events are required to produce a mature mRNA?

Answer 30

Addition of poly A tail, removal of introns and addition of guanylate to the 5’ end via a 5’-5’ triphosphate linkage