The Cell Cycle and DNA Synthesis

During DNA replication, about how many mistakes occur for every 10^10 nucleotides?

When does DNA polymerase proofreading take place?

Which of the following is NOT a checkpoint in the cell cycle?

Which mechanism occurs immediately after an incorrect nucleotide has been added to the growing daughter chain?

What is the function of telomeres in eukaryotes?

What happens to telomeres as cells divide?

What is the catalytic site responsible for proofreading in DNA polymerase?

Which phase of the cell cycle is responsible for DNA synthesis?

What are the three main checkpoints in the cell cycle?

Which proteins are involved in cell cycle regulation in the presence of growth factors and unfavorable conditions?

Which enzyme is responsible for the exonucleolytic proofreading in DNA replication?

What happens to telomeres as cells divide?

What is the function of telomerase in cell division?

Which mechanism is responsible for dealing with the shorter DNA fragment on the lagging strand after RNA primer removal?

DNA Replication and Errors

Approximately one mistake occurs for every 10^10 nucleotides during DNA replication.
DNA polymerase proofreading occurs immediately after the addition of a nucleotide, allowing for correction.

Cell Cycle Checkpoints

G1, G2, and M checkpoints are the three main checkpoints in the cell cycle.
A specific option noted is NOT a checkpoint in the standard cell cycle framework.

Correction Mechanisms

The mechanism that occurs after an incorrect nucleotide is added involves DNA polymerase's exonucleolytic activity, which excises the erroneous nucleotide.
Exonucleolytic proofreading by DNA polymerase is responsible for correcting mistakes.

Telomeres

Telomeres protect the ends of eukaryotic chromosomes and prevent degradation; their function is vital for maintaining genetic stability.
As cells divide, telomeres shorten progressively due to incomplete DNA replication.

Role of Telomerase

Telomerase extends telomeres in certain cells, counteracting the shortening effect during cell division.

Lagging Strand Synthesis

After RNA primer removal, the DNA ligase mechanism fills in the gaps left by the primer, ensuring continuity on the lagging strand.

Cell Cycle Regulation

Proteins involved in cell cycle regulation adapt to the presence of growth factors and respond to unfavorable conditions, ensuring proper control of cell division.

DNA Synthesis Phase

The S phase (synthesis phase) of the cell cycle is responsible for the replication of DNA, preparing the cell for division.

Test your knowledge on the cell cycle and DNA synthesis in this physiology quiz. Explore topics such as cell cycle regulation, checkpoints, and the phases of the cell cycle.