Selected MCQ

Current Question
Telomerase maintains chromosome ends by using a built-in RNA template. In which cells is telomerase typically active?
  • A. Most somatic cells
  • B. Germ cells and many cancer cells
  • C. Red blood cells
  • D. Neurons
Correct Answer: B
Explanation:
Telomerase is active in germline and stem cells (and reactivated in many cancers) to elongate telomeres, but is silent in most somatic cells.
Related Question 1
Crawling movement of cells (e.g., fibroblasts) primarily depends on the polymerization of which cytoskeletal component?
  • A. Microtubules
  • B. Intermediate filaments
  • C. Actin microfilaments
  • D. Centrioles
Correct Answer: C
Explanation:
Lamellipodia and filopodia are actin-based protrusions. Actin polymerization at the leading edge drives cell crawling and motility.
Related Question 2
What is the fundamental unit of heredity that occupies a specific locus on a chromosome?
  • A. Base pair
  • B. Gene
  • C. Chromatin
  • D. Nucleotide
Correct Answer: B
Explanation:
A gene is the hereditary unit at a chromosome locus. It consists of DNA sequences encoding a functional product (RNA or protein).
Related Question 3
In gene therapy using a viral vector, what is a major concern related to using retroviruses?
  • A. They cannot infect human cells
  • B. They only integrate into mitochondrial DNA
  • C. Insertional mutagenesis by random integration into the host genome
  • D. They cannot carry large genes
Correct Answer: C
Explanation:
Retroviral vectors integrate randomly into the host genome, risking insertional mutagenesis (disrupting host genes), which can cause cancer or other issues.
Related Question 4
Which term describes genes that are located on the same chromosome and inherited together more often than by chance?
  • A. Linked genes
  • B. Epistatic genes
  • C. Polygenic genes
  • D. Independent genes
Correct Answer: A
Explanation:
Linked genes are near each other on the same chromosome. They tend to be inherited together, and their recombination frequency is less than 50%.
Related Question 5
Which chromatography technique separates proteins primarily based on size using a gel matrix?
  • A. Ion-exchange chromatography
  • B. Gel filtration (size-exclusion) chromatography
  • C. Affinity chromatography
  • D. Reverse-phase chromatography
Correct Answer: B
Explanation:
Gel filtration chromatography (size-exclusion) separates proteins by size: larger molecules elute first because they enter fewer pores in the matrix, while smaller molecules elute later.