DNA replication and central dogma
- Which of the following statement is correct regarding the process of replication in E.coli? Answer: 1. The DNA dependent DNA polymerase catalyses polymerization in 5' → 3' direction. Key idea: DNA polymerases add nucleotides only in... 1
- Ten E.coli cells with ^15N - dsDNA are incubated in medium containing ^14N nucleotide. After 60 minutes, how many E.coli cells will have DNA totally free from ^15N ? Answer: 4. 60 cells Key idea: DNA replication is semi-conservative, and the question assumes the usual E. coli doubling time of 20 minutes.... 1
- Complete the flow chart on central dogma.(a) DNA (with circular arrow) --(b)--> mRNA --(c)--> (d) Answer: 3. (a)-Replication; (b)-Transcription; (c)-Translation; (d)-Protein The central dogma is DNA to mRNA to protein. The circular arrow... 1
- The experimental proof for semiconservative replication of DNA was first shown in a Answer: 3. Bacterium Meselson and Stahl showed semiconservative replication in 1958 using E. coli. They grew the bacteria in ¹⁵ N medium, sh... 1
- During DNA replication, Okazaki fragments are used to elongate : Answer: 3. The lagging strand away from the replication fork. Key idea: DNA polymerase can add nucleotides only in the 5' to 3' direction. O... 1
- DNA replication in bacteria occurs : Answer: 2. Prior to fission Key idea: Bacteria have no nucleus and no defined cell cycle phases. They have no nucleolus and no S phase (that... 1
- The central dogma of molecular genetics states that the genetic information flows from Answer: 2. DNA → RNA → Proteins Key idea: the central dogma: DNA is transcribed to mRNA, which is translated to protein. Information flows D... 1
- Taylor conducted the experiments to prove semiconservative mode of chromosome replication on Answer: 1. *Vicia faba* Taylor and co-workers (1957) used radioactive thymidine with root tip cells of Vicia faba (broad bean) to show that... 1