Question

1. Which of the following statements is FALSE? Helicase activity 'unwinds DNA making the double-stranded molecule into single strands. b. The leading strand of DNA is started by an RNA primer The lagging strand of DNA is synthesized as "Okazaki fragments", cach with its own RNA primer. DNA replication proceeds in both directions around the bacterial chromosome. DNA polymerase synthesives new DNA in one direction (3 to 5) only. 2. Which of the following would be found in eukaryotes? a. Intervening sequences in mRNA (introns). h. A 5' cap structure on messenger RNA. c. Poly A tail. d. Answers A and B are true e. All of the above are true 3. Which of following antimicrobial drugs inhibit bacterial DNA grase a: Penicillin b. Tetracyclins Quinolones (Ciprofloxin) . Cephalosporins . Aminoglycosides 4. During translation in prokaryotes, the small subunit of the ribosome initially interacts with the mRNA template in what region? a the promotor (P) site b. the operator (0) site PP the initiator (I) site d. the regulatory (R) site e. the Shine-Delgarno sequence Assume 100 E. coli cells in log phase of growth are transferred to a medium containing radioactive Thymin vhich is readily incorporated into DNA). After 1 or more complete generation times, what percentage of th coli cells will contain radioactive thymine incorporated into their DNA? (a. 100%. b. 75%. e. 50%. d. 25%. s. 0%. hich of the following statements regarding mRNA translation in bacteria is/are FALSE 2. Bacterial mRNA associates with the small subunit of the ribosome at the 5 cap structure (6. Bacterial mRNA can encode several different proteins (is polycistronic). 6. The first amino acid incorporated into a protein is always N-formyl methionine « Bacteria contain 70S ribosomes e Translation of bacterial mRNA may begin before transcription is complete,

Answer 1

1)E

DNA polymerase always synthesises new strand from 5' to 3' end

2)E

All the options are correct.all have eukaryotic properties

3) C

Ciproflaxin interfere with the breakage and rejoining of DNA chains

4)E

Purine rich region is called shine dalgarno sequence binds to 16rRNA of 30 s sub unit of ribosome

5)100%

When log phase bacteria introduced into radioactive thymine medium ,bacteria divides and undergo replication of semi conservative type,therefore both cells acquire thymine radioactive.so all cell will have thymine radioactive.100%

6)A

Prokaryotes or bacteria lacks 5'cap