Interphase and part of Telophase of HT1080

Interphase is the active portion of the

cell cycle The cell cycle, or cell-division cycle, is the sequential series of events that take place in a cell (biology), cell that causes it to divide into two daughter cells. These events include the growth of the cell, duplication of its DNA (DNA re ...

that includes the G1, S, and G2 phases, where the cell grows, replicates its DNA, and prepares for

mitosis Mitosis () is a part of the cell cycle in eukaryote, eukaryotic cells in which replicated chromosomes are separated into two new Cell nucleus, nuclei. Cell division by mitosis is an equational division which gives rise to genetically identic ...

, respectively. Interphase was formerly called the "resting phase," but the cell in interphase is not simply dormant. Calling it so would be misleading since a cell in interphase is very busy synthesizing proteins, transcribing DNA into RNA, engulfing extracellular material, and processing signals, to name just a few activities. The cell is quiescent only in G0. Interphase is the phase of the

in which a typical cell spends most of its life. Interphase is the "daily living" or

metabolic Metabolism (, from ''metabolē'', "change") is the set of life-sustaining chemical reactions in organisms. The three main functions of metabolism are: the conversion of the energy in food to energy available to run cellular processes; the ...

phase of the cell, in which the cell obtains

nutrients A nutrient is a substance used by an organism to survive, grow and reproduce. The requirement for dietary nutrient intake applies to animals, plants, fungi and protists. Nutrients can be incorporated into cells for metabolic purposes or excret ...

and metabolizes them, grows, replicates its DNA in preparation for

, and conducts other "normal" cell functions. A common misconception is that interphase is the first stage of

, but since mitosis is the division of the nucleus, prophase is actually the first stage. In interphase, the cell gets itself ready for

meiosis Meiosis () is a special type of cell division of germ cells in sexually-reproducing organisms that produces the gametes, the sperm or egg cells. It involves two rounds of division that ultimately result in four cells, each with only one c ...

. Somatic cells, or normal

diploid Ploidy () is the number of complete sets of chromosomes in a cell, and hence the number of possible alleles for autosomal and pseudoautosomal genes. Here ''sets of chromosomes'' refers to the number of maternal and paternal chromosome copies, ...

cells of the body, go through mitosis in order to reproduce themselves through cell division, whereas diploid

germ cell A germ cell is any cell that gives rise to the gametes of an organism that reproduces sexually. In many animals, the germ cells originate in the primitive streak and migrate via the gut of an embryo to the developing gonads. There, they unde ...

s (i.e., primary spermatocytes and primary oocytes) go through

in order to create haploid gametes (i.e.,

sperm Sperm (: sperm or sperms) is the male reproductive Cell (biology), cell, or gamete, in anisogamous forms of sexual reproduction (forms in which there is a larger, female reproductive cell and a smaller, male one). Animals produce motile sperm ...

and ova) for the purpose of sexual reproduction.

Stages of interphase

There are three stages of cellular interphase, with each phase ending when a cellular checkpoint checks the accuracy of the stage's completion before proceeding to the next. The stages of interphase are: * G₁ (Gap 1), in which the cell grows and functions normally. During this time, a high amount of protein synthesis occurs and the cell grows (to about double its original size) – more

organelle In cell biology, an organelle is a specialized subunit, usually within a cell (biology), cell, that has a specific function. The name ''organelle'' comes from the idea that these structures are parts of cells, as Organ (anatomy), organs are to th ...

s are produced and the volume of the

cytoplasm The cytoplasm describes all the material within a eukaryotic or prokaryotic cell, enclosed by the cell membrane, including the organelles and excluding the nucleus in eukaryotic cells. The material inside the nucleus of a eukaryotic cell a ...

increases. If the cell is not to divide again, it will enter G₀. * Synthesis (S), in which the cell synthesizes its DNA and the amount of DNA is doubled but the number of chromosomes remains constant (via semiconservative replication). * G₂ (Gap 2), in which the cell resumes its growth in preparation for division. The cell continues to grow until mitosis begins. In plants, chloroplasts divide during G2. * In addition, some cells that do not divide often or ever, enter a stage called G₀ (Gap zero), which is either a stage separate from interphase or an extended G₁. The duration of time spent in interphase and in each stage of interphase is variable and depends on both the type of cell and the species of organism it belongs to. Most cells of adult

mammal A mammal () is a vertebrate animal of the Class (biology), class Mammalia (). Mammals are characterised by the presence of milk-producing mammary glands for feeding their young, a broad neocortex region of the brain, fur or hair, and three ...

s spend about 24 hours in interphase; this accounts for about 90%-96% of the total time involved in cell division. Interphase includes G1, S, and G2 phases.

Mitosis Mitosis () is a part of the cell cycle in eukaryote, eukaryotic cells in which replicated chromosomes are separated into two new Cell nucleus, nuclei. Cell division by mitosis is an equational division which gives rise to genetically identic ...

and cytokinesis, however, are separate from interphase. DNA double-strand breaks can be repaired during interphase by two principal processes. The first process,

non-homologous end joining Non-homologous end joining (NHEJ) is a pathway that repairs double-strand breaks in DNA. It is called "non-homologous" because the break ends are directly ligated without the need for a homologous template, in contrast to homology directed repair ...

(NHEJ), can join the two broken ends of DNA in the G1, S and G2 phases of interphase. The second process,

homologous recombination Homologous recombination is a type of genetic recombination in which genetic information is exchanged between two similar or identical molecules of double-stranded or single-stranded nucleic acids (usually DNA as in Cell (biology), cellular organi ...

al repair (HRR), is more accurate than NHEJ in repairing double-strand breaks. However HRR is only active during the S and G2 phases of interphase when

DNA replication In molecular biology, DNA replication is the biological process of producing two identical replicas of DNA from one original DNA molecule. DNA replication occurs in all life, living organisms, acting as the most essential part of heredity, biolog ...

is either partially or fully accomplished, since HRR requires two adjacent homologous chromosomes.

Interphase within sequences of cellular processes

Interphase and the cell cycle

When G₂ is completed, the cell enters a relatively brief period of nuclear and cellular division, composed of mitosis and cytokinesis, respectively. After the successful completion of mitosis and cytokinesis, both resulting daughter cells re-enter G₁ of interphase. In the

, interphase is preceded by telophase and cytokinesis of the M phase. In alternative fashion, interphase is sometimes interrupted by G₀ phase, which, in some circumstances, may then end and be followed by the remaining stages of interphase. After the successful completion of the G₂ checkpoint, the final checkpoint in interphase, the cell proceeds to prophase, or in plants to preprophase, which is the first stage of mitosis. G₀ phase is viewed as either an extended G₁ phase where the cell is neither dividing nor preparing to divide, or as a distinct quiescent stage which occurs outside of the cell cycle.

Interphase and other cellular processes

gamete A gamete ( ) is a Ploidy#Haploid and monoploid, haploid cell that fuses with another haploid cell during fertilization in organisms that Sexual reproduction, reproduce sexually. Gametes are an organism's reproductive cells, also referred to as s ...

production, interphase is succeeded by

. In

programmed cell death Programmed cell death (PCD) sometimes referred to as cell, or cellular suicide is the death of a cell (biology), cell as a result of events inside of a cell, such as apoptosis or autophagy. PCD is carried out in a biological process, which usual ...

, interphase is followed or preempted by

apoptosis Apoptosis (from ) is a form of programmed cell death that occurs in multicellular organisms and in some eukaryotic, single-celled microorganisms such as yeast. Biochemistry, Biochemical events lead to characteristic cell changes (Morphology (biol ...

Interphase (Materials)

The transition region between two materials. For example between the fibre and matrix of a

composite material A composite or composite material (also composition material) is a material which is produced from two or more constituent materials. These constituent materials have notably dissimilar chemical or physical properties and are merged to create a ...

References