Prokaryotic DNA Replication Quiz

DNA Replication

• DNA polymerase is responsible for the formation of phosphodiester bonds during DNA replication.
• In prokaryotic cells, circular bacterial DNA is located in the cytoplasm.

Prokaryotic Cell Division

• Cell division in prokaryotes occurs through a process called binary fission.
• After the replication of the single circular DNA molecule in prokaryotes, the cell divides into two identical daughter cells.

DNA Replication Process

• During DNA replication, one round of replication of a 120 base pair template DNA results in the incorporation of 240 nucleotides.
• This process also produces 240 PPi molecules.
• The enzyme responsible for DNA replication in prokaryotes is DNA polymerase.

DNA Replication Time and Cell Doubling Time

• The approximate DNA replication time in M. tuberculosis is 20-30 minutes.
• The approximate cell doubling time in M. tuberculosis is 15-20 hours.

Eukaryotic Cell Cycle

• In eukaryotes, the S phase of the cell cycle involves chromosome replication and segregation.

DNA Replication in E. coli

• The enzyme that resolves the concatemers formed by daughter DNA molecules in E. coli is DNA topoisomerase IV.
• Ciprofloxacin is an inhibitor of DNA replication in E. coli.
• Mitomycin C and cisplatin are two compounds that cause covalent crosslinking of DNA in E. coli.
• Ciprofloxacin inhibits the resealing of the DNA strand and is used for anthrax infections.
• A point mutation in the gyrA gene can cause resistance to quinolone antibiotics.

Stages of DNA Replication

• The stage that is NOT a part of the replication process in prokaryotes is meiosis.
• Helicase is the enzyme responsible for unwinding the DNA double helix during replication.
• The leading strand is synthesized continuously during replication.
• The lagging strand is synthesized discontinuously in short DNA fragments called Okazaki fragments.
• Primase is the enzyme that adds RNA primers to the DNA template during replication.
• The phase of DNA replication that involves the attachment of the DnaG primase is initiation.
• DNA gyrase is responsible for relaxing positive supercoils during DNA replication.
• DNA polymerase III is the major enzyme for DNA replication in E. coli.
• The sliding clamp protein functions as a processivity factor during DNA replication.
• The molecular weight of the bacterial chromosome in E. coli is approximately 2.5 x 10^9 Da.

Enzymes Involved in DNA Replication

• DNA helicase unwinds the DNA double helix during DNA replication.
• DNA ligase seals the gaps between Okazaki fragments during DNA replication.
• The phase of DNA replication that involves the synthesis of Okazaki fragments is elongation.
• The phase of DNA replication that involves the formation of a primosome is initiation.
• DNA gyrase inhibitors, such as ciprofloxacin, inhibit the relaxation of positive supercoils.

Test your knowledge on the replication of circular bacterial DNA in prokaryotes. Learn about the process of binary fission and the production of identical copies of DNA molecules.