What is circular genome?
Circular DNA is DNA that forms a closed loop and has no ends. Examples include: Plasmids, mobile genetic elements. cccDNA, formed by some viruses inside cell nuclei. Circular bacterial chromosomes.
What is linear DNA replication?
Unlike bacterial chromosomes, the chromosomes of eukaryotes are linear (rod-shaped), meaning that they have ends. These ends pose a problem for DNA replication. When DNA is being copied, one of the two new strands of DNA at a replication fork is made continuously and is called the leading strand.
Why do we have linear DNA?
In general, the factors which led to the evolution of linear chromosomes in eukaryotes are not well understood. One potential selective pressure in favor of linear chromosomes relates to the size of an organism’s genome: linear chromosomes may make transcription and replication of large genomes easier.
Is DNA always perfectly copied during DNA replication?
DNA replication is not perfect, there occurs error after every 104 to 105 nucleotides added. The integrity of the genome is maintained by the proofreading process of DNA polymerase. DNA polymerase moves one step back and removes the incorrectly paired nucleotides by 3’→5′ exonuclease activity.
What is the function of the circular DNA?
It carries genetic material in the form of a linear sequence of deoxyribonucleic acid (DNA ). In prokaryotes, or cells without a nucleus, the chromosome represents circular DNA containing the entire genome.
What happens in G1 and G2?
Initially in G1 phase, the cell grows physically and increases the volume of both protein and organelles. In S phase, the cell copies its DNA to produce two sister chromatids and replicates its nucleosomes. Finally, G2 phase involves further cell growth and organisation of cellular contents.
Is eukaryotic DNA linear?
In eukaryotic cells, chromatin consists of all the DNA within the nucleus and its associated proteins, called histones….Eukaryotic chromosome.
| Eukaryotic Chromosome | Prokaryotic Chromosome | |
|---|---|---|
| Shape | Linear | Circular |
| Size | Large | Small |
| Number | Multiple | Single |
Which contains a linear chromosome?
In most eukaryotic cells, DNA is arranged in multiple linear chromosomes. In contrast, most prokaryotic cells generally contain a singular circular chromosome. However, linear chromosomes are not limited to eukaryotic organisms; some prokaryotic organisms have linear chromosomes as well, such as Borrelia burgdorferi.