Ribosomes Knowledge-Based Download PDF

Questions

1. 1.

   Which of the following characteristics fundamentally distinguishes ribosomes from organelles such as mitochondria, lysosomes, and the endoplasmic reticulum?

   • A) Their restriction exclusively to eukaryotic organisms
   • B) Their lack of a surrounding phospholipid bilayer membrane
   • C) Their functional dependence on autonomous binary fission for replication
   • D) Their direct synthesis of lipid molecules to build cellular compartments
2. 2.

   Which catalytic activity of the ribosome is directly responsible for joining adjacent amino acids together during the synthesis of a polypeptide chain?

   • A) Aminoacyl-tRNA synthetase activity
   • B) Phosphodiester bond formation
   • C) Signal peptide cleavage
   • D) Peptidyl transferase activity
3. 3.

   In eukaryotic cells, which specialized nuclear structure is directly responsible for synthesizing ribosomal RNA (rRNA) and assembling it with imported proteins into ribosomal subunits?

   • A) Golgi apparatus
   • B) Nucleolus
   • C) Smooth endoplasmic reticulum
   • D) Centrosome
4. 4.

   Which of the following statements accurately describes the structural composition and organization of ribosomes?

   • A) They are non-membrane-bound complexes composed of ribosomal RNA (rRNA) and proteins organized into two unequal subunits.
   • B) They are single-membrane-bound organelles composed of phospholipid bilayers surrounding a core of enzymatic proteins.
   • C) They are double-membrane-bound structures containing transfer RNA (tRNA) and genomic DNA organized into three symmetrical subunits.
   • D) They are membranous vesicles composed exclusively of catalytic messenger RNA (mRNA) molecules without any protein component.
5. 5.

   Which statement correctly distinguishes the primary destinations of proteins synthesized by free ribosomes from those produced by bound ribosomes?

   • A) Free ribosomes synthesize proteins destined for secretion or lysosomes, whereas bound ribosomes produce proteins that function within the cytosol.
   • B) Ribosomes are enclosed by a single phospholipid bilayer that regulates the transport of completed polypeptides into the cytosol or lumen.
   • C) Free ribosomes primarily produce proteins that function within the cytosol, whereas bound ribosomes synthesize proteins destined for membrane insertion, organelle packaging, or secretion.
   • D) Bound ribosomes contain ribosomal RNA and catalytic proteins, whereas free ribosomes consist exclusively of polypeptides devoid of nucleic acids.