Question

Decide the sentences are True or False, and show as T or F

1. The basis of precipitation of proteins by ammonium sulfate is described by ammonium sulfate binds water molecules, making them less available for hydration of proteins.
2. The most efficient substrate of an enzyme is usually considered to be the substrate with the largest kcat/Km.
3. Peripheral membrane proteins behave like typical soluble proteins when released from membranes.
4. An integral membrane protein will commonly be solubilized by extraction with a chelating agent that removes divalent cations.
5. Sickle cell is caused by abnormally-shaped hemoglobin. The only difference between normal and sickle cell hemoglobin is one different amino acid.
6. During the formation of the peptide bond hydrogen atom is lost from its carboxyl group of one amino acid and a hydroxyl group is lost from its amino group of another amino acid.
7. As you know, the thymidine analog 3'-azidothymidine (AZT) blocks replication of human immunodeficiency virus (HIV). AZT is converted in cells to the 5'-triphosphate nucleotide derivative and then incorporated into cDNA copies of the infecting HIV RNA by the HIV's own reverse transcriptase. The cDNA terminates prematurely at the point of the inserted analog. The most likely reason that AZT is not equally inhibitory toward replication of human DNA is that the 5'-triphosphate nucleotide derivative is hydrolyzed by nuclear enzymes to the thymidine-5'-triphosphate, so the azido-form is not incorporated into replicating DNA.
8. Molecular chaperons are proteins that interact with partially folded polypeptides, facilitating correct folding pathways in which folding can occur.
9. Excluding the amino acid glycine, all other amino acids found within human proteins are of the L configuration.
10. The amino acid sequence of a protein determines its three dimensional shape.
11. MALDI is an ionization technique for mass spectrometry which involves suspension of the peptides (or other biomolecules) in an organic matrix followed by vaporization using a laser.
12. Vander Waals forces aids in keeping protein stable and biologically active by allowing the protein to reduce its surface area.
13. Peptide bonds formation involves hydration reactions.
14. Quaternary structure is most likely to be preserved when a protein is denatured.
15. Insulin is the only example of a protein with quaternary structure.

Answer 1

1. The basis of precipitation of proteins by ammonium sulfate is described by ammonium sulfate binds water molecules, making them less available for hydration of proteins. Answer T

2. The most efficient substrate of an enzyme is usually considered to be the substrate with the largest kcat/Km. Answer T

3. Peripheral membrane proteins behave like typical soluble proteins when released from membranes. Answer F

4.An integral membrane protein will commonly be solubilized by extraction with a chelating agent that removes divalent cations. Answer F

5. Sickle cell is caused by abnormally-shaped hemoglobin. The only difference between normal and sickle cell hemoglobin is one different amino acid. Answer T