Briefly describe the procedure of DNA replication. compare prokaryotic and also eukaryotic DNA replication in terms of origins of replication. Define telomeres and also state even if it is they are discovered in prokaryotic or eukaryotic DNA. Surname the stages of mitosis and also state what happens during each.

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As in prokaryotes, the direct chromosomes of eukaryotes replicate by strand separation and complementary base pairing of cost-free deoxyribonucleotides through those ~ above each parental DNA strand. As with prokaryotes, DNA replication in eukaryotic cells is bidirectional. However, uneven the one DNA in prokaryotic cells the usually has a single origin that replication, the linear DNA that a eukaryotic cell contains multiple origins of replication (Figure (PageIndex11)).

Figure (PageIndex11): Bidirectional DNA Replication in eukaryotic Cells. DNA replication (arrows) wake up in both direction from multiple beginnings of replication in the straight DNA discovered in eukaryotic cells.As debated earlier under prokaryotic DNA replication, DNA have the right to only it is in synthesized in a 5" come 3" direction and all DNA polymerase needs a primer. To deal with this problem, the ends of the linear eukaryotic DNA strands, called telomeres , have actually short, repetitive, noncoding DNA basic sequences. A distinct enzyme called telomerase binds to the telomeric DNA at the 3" end. The telomerase includes a tiny RNA layout as a cofactor i m sorry is duplicated by DNA nucleotides to extend the 3" end. As soon as the extension is lengthy enough, primase can assemble a quick RNA primer on the lagging strand and DNA replication can proceed in a manner similar to the lagging strand of prokaryotes DNA.


Animation: Replication of DNA by Complementary basic Pairing. Together the DNA strands unwind and also separate, brand-new complementary strands are developed by the hydrogen bonding of totally free DNA nucleotides through those on each parent strand. As the new nucleotides heat up opposite each parental strand through hydrogen bonding, enzymes called DNA polymerases sign up with the nucleotides by means of phosphodiester bonds. The DNA polymerase responsible for these events is not presented here.

Once the chromosomes have actually replicated, the nucleus divides by mitosis (see number (PageIndex12) v 16). The eukaryotic cell bike is divided into two significant phases: interphase and also cell division.

Interphase in a plant cell: see number (PageIndex17)

Figure (PageIndex17): Interphase in a plant Cell. Ninety percent or more of the cabinet cycle is invested in interphase. During interphase, cellular organelles twin in number, the DNA replicates, and protein synthetic occurs. The chromosomes are not visible and also the DNA shows up as uncoiled chromatin.These room cells uncovered in the roor guideline of one onion plant.

Interphase in an pet cell: see figure (PageIndex18)

Figure (PageIndex18): Interphase in an pet Cell. Ninety percent or more of the cell cycle is invested in interphase. Throughout interphase, to move organelles double in number, the DNA replicates, and also protein synthesis occurs. The chromosomes room not visible and also the DNA appears as uncoiled chromatin. These are cells native a whitefish.

Interphase is separated into the following stages: G1, S, and G2.

G1 phase: throughout G1 phase, the duration that instantly follows cabinet division, the cell grows and differentiates. New organelles space made however the chromosomes have actually not however replicated in ready for cabinet division. S phase: DNA synthesis occurs throughout S phase. The chromosomes replicate in preparation for cell division. G2 phase: throughout G2 phase, molecule that will certainly be forced for cabinet replication space synthesized.

Cell Division

Cell department consists of nuclear department and cytoplasmic division. Nuclear division is described as mitosis when cytoplasmic division is called cytokenesis.

1. Mitosis (nuclear division)

Mitosis is the nuclear department process in eukaryotic cells and also ensures the each daughter cell receives the same variety of chromosomes as the original parent cell. Mitosis have the right to be divided into the complying with phases: prophase, metaphase, anaphase, and telophase.

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Prophase in a plant cell: see figure (PageIndex19) and also Figure (PageIndex20)

Prophase in an pet cell: see number (PageIndex21) and Figure (PageIndex22)

b. Metaphase: throughout metaphase, the atom membrane fragmentation is complete and the duplicated chromosomes line up along the cell"s equator.

d. Telophase: during telophase, the nuclear membrane and nucleoli reform, cytokinesis is almost complete, and the chromosomes at some point uncoil to chromatin. Typically cytokinesis occurs during telophase.