Multiple Choice Questions on Protein Sorting or Protein Targeting

 1. The process of sorting and transporting newly synthesized proteins to correct destination in a cell is called

a) protein sorting
b) protein targeting
c) protein trafficking
d) all of these

2. Proteins required in the cytosol like the enzymes of glycolysis are synthesized on
a) ribosomes on endoplasmic reticulum
b) SER
c) free ribosomes in the cytosol
d) ribosomes on nuclear membrane


3. Secretory proteins are synthesized by
a) free ribosome
b) ribosomes on endoplasmic reticulum
c) ribosomes on nuclear membrane
d) all of the above

4. Choose the correct order of transport of protein in a secretory pathway?
a) Protein synthesized in the cytoplasm->SER lumen->RER lumen->cis golgi->median golgi->trans golgi->vescicles->fusion of vesicles with plasma membrane-> exocytosis
b) Protein synthesized in the cytoplasm->RER lumen->cis golgi->median golgi->trans golgi->vescicles->fusion of vesicles with plasma membrane-> exocytosis
c) Protein synthesized in the cytoplasm->vescicles->SER->RER lumen->cis golgi->median golgi->trans golgi->vescicles->fusion of vesicles with plasma membrane-> exocytosis
d) Protein synthesized in the cytoplasm->RER lumen->trans golgi->median golgi->cis golgi->vesicles->fusion of vesicles with plasma membrane-> exocytosis

5. According to signal hypothesis, the signal peptide for a secretory protein is
a) rich in hydrophobic amino acids at the centre of the signal peptide and is attached to the N-terminus of the protein
b) rich in hydrophilic amino acids at the centre of the signal peptide and is attached to the N-terminus of the protein
c) rich in hydrophobic amino acids at the centre of the signal peptide and is attached to the C-terminus of the protein
d) rich in Sulphur containing amino acids at the centre of the signal peptide and is attached to the N-terminus of the protein

6. Signal sequences are
a) short peptide sequences that serves as an address for transporting newly synthesized proteins to the correct location
b) glycoprotiens that serves as an address for transporting newly synthesized proteins to the correct location
c) short peptide sequences to transport a protein to the nucleus
d) short peptide sequences attached to a protein that initiates its degradation by digestive enzymes

7. The retention signal of proteins of endoplasmic reticulum consists of aminoacids
a) Gly—Asp-Glu-Leu at the N- terminus
b) Lys—Asp-Glu-Leu at the N- terminus
c) Gly—Asp-Glu-Leu at the C- terminus
d) Lys—Asp-Glu-Leu at the C- terminus

8. Proteins tagged with mannose 6-phospahte are transported to
a) nucleus
b) lysosome
c) mitochondrion
d) golgi apparatus

9. Nuclear localization signal that ensures transport of a protein to nucleus is rich in
a) lysine and arginine
b) glutamine and asparagine
c) serine and threonine
d) tryptophan and histidine

10. Proteins targeted to mitochondrial matrix are tagged with matrix targeting sequence rich in
a) serine and threonine
b) serine, threonine, lysine and arginine
c) serine, threonine, glutamine and asparagine
d) serine, threonine tryptophan and histidine

Learn More:

• Multiple Choice Question on Proteins
• Multiple Choice Question on Protein Denaturation
• Multiple Choice Question on Protein Function
• Multiple Choice Question on Protein Purification

Answers:
1. d) all of these
2. c) free ribosomes in the cytosol
3. b) ribosomes on endoplasmic reticulam
4. b) Protein synthesized in the cytoplasm->RER lumen->cis golgi->median golgi->trans golgi->vescicles->fusion of vesicles with plasma membrane-> exocytosis
5. a) rich in hydrophobic amino acids at the centre of the signal peptide and is attached to the N-terminus of the protein
6. a) short peptide sequences that serves as an address for transporting newly synthesized proteins to the correct location
7. d) Lys—Asp-Glu-Leu at the C- terminus
8. b) lysosome
9. a) lysine and arginine
10. b) serine, threonine, lysine and arginine