DNA Replication General Principles

A set of flashcards covering key concepts related to DNA replication, including processes, enzymes, and specific characteristics in prokaryotic and eukaryotic cells.

What is the purpose of DNA replication in a cell?

To copy the entire genome before cell division.

During which phase of the cell cycle does DNA replication occur?

S-phase.

What is the replication speed of DNA in bacteria?

5000 base pairs per second (bp/sec).

What is the replication speed of DNA in eukaryotes?

5000 base pairs per minute (bp/min).

What is a mutation in the context of DNA?

A change in a gene sequence that impacts product function, creating new alleles.

What is a replicon?

A unit of DNA that is replicated and has an origin of replication.

How many replicons do prokaryotic cells typically have?

One single replicon.

How many replicons are typically found in eukaryotic cells?

Multiple replicons due to larger, linear chromosomes.

What direction is DNA synthesized during replication?

5' to 3' direction.

What is the role of DNA helicase in DNA replication?

To break hydrogen bonds between bases and unwind the double helix.

What are Single-strand Binding Proteins (SSBPs)?

Proteins that prevent DNA strands from interacting and forming secondary structures.

What is the function of DNA Gyrase?

To prevent torsional strain during DNA unwinding by cutting and rejoining strands.

What role does primase play in DNA replication?

It synthesizes short complementary RNA strands called primers.

What is the primary function of DNA polymerase III?

To add DNA nucleotides to the 3'-end of a primer and proofread DNA.

What is unique about DNA polymerase I?

It has low processivity and removes RNA primers while adding bases to adjacent DNA strands.

What is the role of DNA Ligase in DNA replication?

To join adjacent DNA fragments together by making phosphodiester bonds.

What is the importance of mismatch repair?

To detect and repair errors after DNA replication is complete, reducing mutation rates.

What are some challenges of eukaryotic DNA replication?

Eukaryotic chromosomes are linear and larger, requiring multiple origins of replication.

What proteins are responsible for initiating DNA replication in eukaryotes?

Origin recognition complex (ORC) proteins.

What is telomerase and its role in DNA replication?

An enzyme that adds repeated sequences to telomeres, protecting chromosome ends from degradation.

How does DNA replication affect chromosome length over time?

Telomeres shorten with each replication, potentially leading to chromosome shortening.