biology mcqs
Test your comprehensive knowledge of DNA structure, replication, transcription, genetic code, translation, gene regulation, the Human Genome Project, and DNA fingerprinting with these challenging multiple-choice questions.
Showing questions 21 - 40 of 169
21. The calculated length of DNA double helix in a typical mammalian cell is approximately 2.2 metres. How does this compare to the dimension of a typical nucleus?
22. Which basic amino acid residues are abundant in histones, contributing to their positive charge?
23. What structure is formed when the negatively charged DNA wraps around the positively charged histone octamer?
24. A typical nucleosome contains approximately how many base pairs of DNA helix?
25. When viewed under an electron microscope, how do nucleosomes appear in chromatin?
26. What are the two types of chromatin found in a typical nucleus based on their packing density and staining?
27. Which type of chromatin is transcriptionally active, and which is inactive?
28. At the time of Mendel, what was the nature of the 'factors' regulating inheritance?
29. Frederick Griffith conducted experiments on transformation using which bacterium?
30. In Griffith's experiment, which strain of *Streptococcus pneumoniae* had a mucous coat and was virulent, causing pneumonia?
31. What did Griffith conclude from his experiment where injecting a mixture of heat-killed S and live R bacteria killed mice and living S bacteria were recovered?
32. Who worked to determine the biochemical nature of the 'transforming principle' in Griffith's experiment?
33. Avery, MacLeod, and McCarty discovered that which purified biochemical alone from S bacteria caused R bacteria to become transformed?
34. What effect did protein-digesting enzymes (proteases) and RNA-digesting enzymes (RNases) have on transformation in Avery, MacLeod, and McCarty's experiment?
35. What was the effect of digestion with DNase on transformation in Avery, MacLeod, and McCarty's experiment?
36. The unequivocal proof that DNA is the genetic material came from the experiments of whom?
37. Hershey and Chase worked with which organisms to prove that DNA is the genetic material?
38. In the Hershey-Chase experiment, which radioactive isotopes were used to label DNA and protein, respectively?
39. What was the key finding from the Hershey-Chase experiment that indicated DNA was the genetic material?
40. In which organisms is RNA known to be the genetic material?