How is replication regulated in eukaryotes?
Eukaryotic DNA replication is regulated to ensure all chromosomes replicate once and only once per cell cycle. Cell cycle regulation by protein phosphorylation ensures that pre-RC assembly can only occur in G1 phase, whereas helicase activation and loading can only occur in S phase.
What is a major difference between eukaryotic DNA replication and prokaryotic DNA replication?
Prokaryotic Replication vs Eukaryotic Replication
| Prokaryotic Replication | Eukaryotic Replication |
|---|---|
| It is a continuous process. | This process occurs in the S-phase of cell cycle. |
| Circular, double-stranded DNA | Linear, double-stranded DNA with end |
| The DNA replicates in the cytoplasm | The DNA replicates in the nucleus |
Where does replication take place in eukaryotes?
the nucleus
Eukaryotic DNA replication requires multiple replication forks, while prokaryotic replication uses a single origin to rapidly replicate the entire genome. DNA replication always occurs in the nucleus. Eukaryotic DNA replication involves more polymerases than prokaryotic replication.
How do chloroplasts replicate?
Replication. The only way these organelles can be replicated is through the same method used by bacteria: binary fission. Like bacteria, mitochondria and chloroplasts grow in size, duplicate their DNA and other structures, and then divide into two identical organelles.
How is replication initiation regulated in prokaryotes and in eukaryotes?
The initiation of chromosomal replication occurs only once during the cell cycle in both prokaryotes and eukaryotes. Bacterial chromosome replication is initiated at a single origin, oriC , by the initiator protein DnaA, which specifically interacts with 9-bp nonpalindromic sequences (DnaA boxes) at oriC .
How initiation of replication is regulated in prokaryotes?
Regulation. Chromosome replication in bacteria is regulated at the initiation stage. DnaA-ATP is hydrolyzed into the inactive DnaA-ADP by RIDA (Regulatory Inactivation of DnaA), and converted back to the active DnaA-ATP form by DARS (DnaA Reactivating Sequence, which is itself regulated by Fis and IHF).
How do replication transcription and translation differ in prokaryotes and eukaryotes?
In eukaryotes, transcription and translation take place in different cellular compartments: transcription takes place in the membrane-bounded nucleus, whereas translation takes place outside the nucleus in the cytoplasm. In prokaryotes, the two processes are closely coupled (Figure 28.15).
How does DNA in eukaryotes differ from prokaryotes?
The prokaryotic cells have no nucleus, no organelles and a very small amount of DNA. On the other hand, the eukaryotic cells have nucleus and cell organelles, and the amount of DNA present is large.
Where does the replication process start initiated and when replication takes place in eukaryotes?
Initiation of DNA replication in eukaryotes begins with the binding of the origin recognition complex (ORC) to origins of replication during the G1 phase of the cell cycle. The ORC complex then serves as a platform for forming much more complicated pre-replicative complexes (pre-RCs).
Is replication bidirectional in eukaryotes?
As with prokaryotes, DNA replication in eukaryotic cells is bidirectional. However, unlike the circular DNA in prokaryotic cells that usually has a single origin of replication, the linear DNA of a eukaryotic cell contains multiple origins of replication (Figure 19.5. 11).
How are mitochondria replicated within eukaryotic cells?
Mitochondria cannot be made “from scratch” because they need both mitochondrial and nuclear gene products. These organelles replicate by dividing in two, using a process similar to the simple, asexual form of cell division employed by bacteria.
During which part of the cell cycle is the DNA replicated doubled )?
interphase
The cell cycle consists of interphase and the mitotic phase. During interphase, the cell grows and the nuclear DNA is duplicated.