Selected MCQ

Current Question
Somatic cell nuclear transfer (SCNT) for reproductive cloning involves:
  • A. Injecting somatic cell DNA into a fertilized egg with its nucleus intact
  • B. Fusing a diploid somatic cell with an enucleated egg cell
  • C. Using only oocyte mitochondria from a donor
  • D. Cloning via binary fission
Correct Answer: B
Explanation:
SCNT (as in cloning Dolly the sheep) entails transferring the nucleus of an adult somatic cell into an enucleated oocyte, and then stimulating the resulting cell to divide as an embryo.
Related Question 1
The technique for producing monoclonal antibodies involves fusing a specific antibody-producing B cell with a myeloma cell (a cancer cell). This hybrid cell line is called a:
  • A. Bacteriophage
  • B. Hybridoma
  • C. Plasmid
  • D. Complement
Correct Answer: B
Explanation:
A hybridoma results from fusing a single B lymphocyte (which produces one antibody) with a myeloma cell, creating an immortal cell line that produces identical (monoclonal) antibodies.
Related Question 2
Which statement correctly describes the role of nuclear pore complexes in eukaryotic cells?
  • A. They allow passive diffusion of all proteins smaller than ~100 kDa
  • B. They actively transport large molecules into and out of the nucleus
  • C. They separate the nuclear interior from the cytosol without any transport
  • D. They are the sites where rRNA is transcribed and processed
Correct Answer: B
Explanation:
Nuclear pore complexes selectively transport large molecules (such as mRNA and proteins with nuclear localization/export signals) between the nucleus and the cytoplasm. Small molecules can diffuse passively up to ~40 kDa.
Related Question 3
A mutation in nuclear lamin would most directly impair which cellular structure?
  • A. Alignment of chromosomes during metaphase
  • B. Anchoring of the nucleus to the cytoskeleton
  • C. Organization and structural integrity of the nuclear envelope
  • D. Export of mRNA through nuclear pores
Correct Answer: C
Explanation:
Lamins are intermediate filament proteins that form a network lining the inner nuclear membrane. Mutations disrupt the nuclear envelope’s stability and organization.
Related Question 4
Why is the G0 phase considered distinct from G1 in the cell cycle?
  • A. G0 cells are rapidly dividing
  • B. G0 is a quiescent/nondividing state outside the normal cycle
  • C. G0 occurs immediately after the M phase in all cells
  • D. Cells in G0 cannot re-enter the cell cycle under any condition
Correct Answer: B
Explanation:
G0 is a resting or terminal differentiation state where cells are metabolically active but not dividing. Cells can re-enter G1 from G0 given appropriate signals.
Related Question 5
In flow cytometry, cells are labeled with fluorescent antibodies and passed in a stream through a laser. This technique primarily measures:
  • A. Cell size and internal complexity
  • B. DNA sequence variants
  • C. Protein structure by X-ray diffraction
  • D. Glycolytic activity
Correct Answer: A
Explanation:
Flow cytometry measures light scattering (size and granularity) and fluorescence from labeled markers, allowing rapid analysis of cell populations (size, complexity, marker expression).