BIOL 3301 Lecture Notes - Lecture 9: Secretion, Cell Membrane, Nuclear Membrane

3. For each alternative ending to the following sentence, indicate why the ending is false: 4 pts

“Proteins destined to enter the rough endoplasmic reticulum _______”

a. are transported into the ER after their synthesis is complete.

b. are synthesized on free ribosomes in the cytosol.

c. cross the membrane in a folded state.

d. must be proteins that will be secreted from the cell.

29 Most proteins destined to enter the endoplasmic reticulum _________.

(a) are transported across the membrane after their synthesis is complete.

(b) are synthesized on free ribosomes in the cytosol.

(c) begin to cross the membrane while still being synthesized.

(d) are keep binding to Signal recognition particle (SRP) while they are translated.

30 Which of the following choices reflects the appropriate order of locations through which a protein destined for the plasma membrane travels?

(a) lysosome → endosome → plasma membrane

(b) ER → lysosome → plasma membrane

(c) Golgi → lysosome → plasma membrane

(d) ER → Golgi → plasma membrane

31 Which of the following statements about vesicle budding from the Golgi is false?

(a) COPII can initiate vesicle budding on Golgi membrane.

(b) Some vesicles budded from Golgi membranes move towards ER.

(c) Once vesicle budding completed, clathrin molecules are released from the vesicle.

(d) Clathrin molecules act at the cytosolic surface of the Golgi membrane.

32 Which of the following statements is false?

(a) The signal sequences on mitochondrial proteins are first bound to translocator on outer membrane after translation.

(b) Most mitochondrial proteins are not imported from the cytosol but are synthesized inside the mitochondria.

(c) Chaperone proteins in the mitochondria facilitate the movement of proteins across the outer and inner mitochondrial membranes.

(d) Mitochondrial proteins cross the membrane in their unfolded state.

1A. Which of the following statements about the endomembrane system is/are correct? (select all that apply)

1B. Place these components of the endomembrane system into the correct order in respect to when they first function in the production of a secreted protein.