chapter 15 Flashcards
What is the primary function of lysosomes within the cell? A) Protein synthesis B) Lipid synthesis C) Intracellular degradation D) Protein glycosylation
C
The site of most lipid synthesis and initial protein synthesis for export in the cell is the: A) Golgi apparatus B) Endosomes C) Endoplasmic Reticulum D) Mitochondria
C
Proteins destined for the nucleus enter via which transport mechanism? A) Vesicular transport B) Transmembrane transport C) Gated transport D) Passive diffusion
C
Which organelle is primarily involved in detoxifying drugs in liver cells? A) Rough ER B) Smooth ER C) Golgi apparatus D) Lysosomes
B
What is the role of the SRP in protein synthesis? A) Binds DNA to initiate transcription B) Targets ribosomes to the ER membrane C) Catalyzes peptide bonds D) Transports proteins into the nucleus
B
The process by which proteins travel between organelles via small membrane-bound compartments is called: A) Gated transport B) Vesicular transport C) Transmembrane transport D) Direct diffusion
B
Signal sequences that target proteins to specific cellular compartments are typically found at which protein region? A) N-terminus B) C-terminus C) Central domain D) Variable depending on protein
A
What mechanism ensures improperly folded proteins do not exit the ER? A) Retrograde transport B) Unfolded protein response (UPR) C) Glycosylation D) Proteasomal digestion
B
Which modification stabilizes proteins by forming bonds between cysteine residues in the ER? A) Glycosylation B) Phosphorylation C) Acetylation D) Disulfide bond formation
D
Which cellular compartment occupies the largest volume in a typical eukaryotic cell? A) Mitochondria B) Cytosol C) Golgi apparatus D) Endoplasmic Reticulum
B
The ER lumen is topologically equivalent to: A) The mitochondrial matrix B) Cytosol C) The outside of the cell D) Nuclear lumen
C
Which structure mediates nuclear import of proteins containing an NLS? A) Lysosomes B) Nuclear pores C) Golgi apparatus D) Endosomes
B
Misfolded proteins identified in the ER are exported to the cytosol for degradation by which structure? A) Lysosomes B) Endosomes C) Proteasomes D) Golgi apparatus
C
What determines the orientation of transmembrane proteins in the ER membrane? A) Presence of charged amino acids in the signal sequence B) Lipid composition C) Protein glycosylation D) Protein folding speed
A
Which ER-associated molecule directly catalyzes glycosylation of newly synthesized proteins? A) Protein disulfide isomerase B) Signal recognition particle C) Oligosaccharyl transferase D) ATP synthase
C
In eukaryotic cells, organelles are enclosed by lipid bilayers, forming distinct compartments.
t
The Golgi apparatus is directly continuous with the nuclear envelope.
f
Mitochondria participate actively in vesicle trafficking pathways within the cell.
f
The rough ER is characterized by the presence of ribosomes on its cytosolic surface.
t
Protein glycosylation occurs primarily in the Golgi apparatus, not in the ER.
f
Peroxisomes primarily degrade proteins via proteasomes.
f
An unfolded protein response (UPR) occurs when misfolded proteins accumulate in the ER lumen.
t
Proteins synthesized by free ribosomes in the cytosol are typically destined for mitochondria or chloroplasts.
t
Proteins destined for secretion from the cell are synthesized directly into the ER lumen.
t
