Selected MCQ

Current Question
A red blood cell (internal osmolarity ~290 mOsm) is placed in a 100 mM NaCl solution (assume full dissociation). Which best describes the movement of water?
  • A. The cell loses water and shrinks
  • B. The cell gains water and swells
  • C. No net water movement
  • D. The cell bursts immediately
Correct Answer: B
Explanation:
100 mM NaCl yields ~200 mOsm outside (hypotonic to the cell). Water enters the cell, causing it to swell.
Related Question 1
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 2
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 3
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).
Related Question 4
Pluripotent stem cells are characterized by their ability to:
  • A. Differentiate into all cell types, including extraembryonic membranes
  • B. Differentiate into any cell type of the body (but not extraembryonic tissues)
  • C. Self-renew indefinitely but only become one cell type
  • D. Be harvested from adult muscle tissue
Correct Answer: B
Explanation:
Pluripotent stem cells (like embryonic stem cells) can form any body cell type (endoderm, mesoderm, ectoderm) but cannot form an entire organism (unlike totipotent zygotes).
Related Question 5
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.