Interphase: Definition, Explanation & Process

All living things require the process of cell division to grow and reproduce. To prepare the cell for the next division, it goes into interphase.

Interphase—Definition & Explanation

The phase between two nuclear divisions is called interphase designated. she takes place between the last and next mitosis instead of. Therefore it is also the longest phase of the cell cycle. In some cells, it takes up 90% of the entire cycle.

In the interphase, the cells are prepared for the upcoming cell division. For this purpose, cells are multiplied and non-existent cell components are supplemented. The chromosomes are then duplicated. In the phase, the cell is prepared for the next mitosis, the normal functions of the cells continue to be carried out during this time.

In order to control the precise phase transitions, there are so-called cell cycle checkpoints. In the interphase there are two of them. The G1 checkpoint, located between the G1 and S phases, and the G2 checkpoint. This is at the transition between the G2 phase and the subsequent mitosis.

Here it is checked whether the DNA is intact and has been properly replicated. In this way, the cell cycle checkpoints are supposed to protect the genetic material and prevent «degeneration», i.e. a negative change in the cell.

Interphase process – phases simply explained

Interphase can be divided into three phases: G1 phase, S phase and G2 phase. There is also a rest phase (G0 phase), which is only optional.

Figure 1: Schematic representation of the cell cycle. The green arrow after M shows that the cell can switch to the G0 phase during the G1 phase Source: wikipedia.org

G1 phase

The G1 phase is also called the gap phase and marks the beginning of the interphase. It takes place right after the last cytokinesis.

Cytokinesis is just another term for cell division.

During this phase, the cell grows rapidly as it prepares for the next cell division. Protein biosynthesis is boosted because histones and replication enzymes are needed for S-phase. In addition, cell components such as the cytoplasm or the cell organelles are supplemented.

In addition to preparing for the next mitosis, the cell continues to carry out its actual tasks.

In animal cells, both centrioles are separated from each other, so that each chromosome consists of only one chromatid, so they are Unichromatid chromosomes. They are now in the de-spiraled state.

The duration of the G1 phase can vary from one to twelve hours.

G0 phase

If cells are not supposed to or cannot continue to multiply at the moment, they switch from the G1 phase to the G0 phase. In this state they can last a few days or even several years remain.

lymphocytes (white blood cells) remain in the G0 phase until they are stimulated by a specific antigen to re-enter the cell cycle.

Even if these cells are, as it were, in one, as far as cell division is concerned sleep mode (dormant cell) are located, they continue to carry out their intended function. Some cell types, such as nerve cells and striated muscle cells, never divide again and are permanently in the G0 phase.

S phase

During the S phase, also called the synthesis phase, the doubling of the individual chromatids. So DNA replication occurs. Since the centrioles are also doubled, all the chromosomes are back as one at the end of the S phase Two chromatid chromosomes before.

In humans, the S phase takes about seven to eight hours.

G2 phase

In the G2 phase, the cell continues to grow through liquid absorption and protein biosynthesis and RNA synthesis take place again. In this way, the immediately following mitosis is prepared. These preparations also include melting down the endoplasmic reticulum and detaching the contact points to neighboring cells.

The G2 phase takes about four hours.

Interphase – mitosis

Mitosis is the M phase. she finds after the interphase takes place. During mitosis, the cell’s nucleus is divided. Cytokinesis (cell division) then produces two identical daughter cells.

Mitosis consists of four phases: prophase, metaphase, anaphase and telophase.

prophase

The chromosomes change back from the decoiled to the coiled, typical form. The spindle apparatus forms and the nuclear envelope dissolves.

metaphase

The chromosomes line up at the center of the cell (also called the equatorial plane). The spindle fibers of the spindle apparatus spread out and attach to the centromeres from both sides.

anaphase

The chromosomes are divided as the spindle fibers each pull a chromatid to their side.

telophase

The spindle fibers dissolve. New nuclear envelopes form around the two sets of unichromatid chromosomes.

After this, cytokinesis takes place, causing the rest of the cell to divide. Finally, there are two identical daughter cells, both of which have a one-chromatid set of chromosomes. Now the cell re-enters the G1 phase of interphase.

You can find more information on the individual phases of mitosis in the corresponding sub-chapters under the chapter «Mitosis».

Interphase – meiosis

arise during meiosis germ cellsalso sex cells called. The phase generally occurs before fertilization. Meiosis is composed consists of two sections (meiosis 1 and 2). the interphase takes place in meiosis only before meiosis 1.

Meiosis 1 consists of the four phases: prophase 1, metaphase 1, anaphase 1 and telophase 1. Meiosis 2 consists of the four phases: prophase 2, metaphase 2, anaphase 2 and telophase 2.

Interphase – The most important thing

  • The interphase is a phase of the cell cycle that occurs between two mitoses.
  • Interphase can be divided into three phases: G1 phase, S phase and G2 phase. There is also an optional G0 phase.
  • During the G1 phase, the cell grows and the centrioles separate so that each chromosome consists of just one chromatid; so they are monochromatid chromosomes.
  • In the G0 phase, the cell pauses the cell cycle and no cell division takes place.
  • During the S phase, the chromosomes are duplicated.
  • During the G2 phase, the cell continues to grow and the final preparations for mitosis take place.
  • Mitosis is carried out after the interphase. The cell nucleus is duplicated and then the cell itself as well.