#Prophase 1 diagram code
#Prophase 1 diagram series

#Prophase 1 diagram series

Watch this video about the cell cycle: Figure 6.3 A cell moves through a series of phases in an orderly manner. During the mitotic phase, the replicated DNA and cytoplasmic contents are separated and the cell divides. During interphase, the cell grows and DNA is replicated. The cell cycle has two major phases: interphase and the mitotic phase ( Figure 6.3). Cells on the path to cell division proceed through a series of precisely timed and carefully regulated stages of growth, DNA replication, and division that produce two genetically identical cells.

The cell cycle is an ordered series of events involving cell growth and cell division that produces two new daughter cells. Explain how the three internal control checkpoints occur at the end of G 1, at the G 2–M transition, and during metaphase.Discuss the behavior of chromosomes during mitosis and how the cytoplasmic content divides during cytokinesis.Describe the three stages of interphase.Microtubules from one centrosome attach to the kinetochore (protein structures at the centromeres) of one chromosome from each of the homologous pairs, while the other centrosome connects to the kinetochore of the other chromosome in each homologous pair, and each homologous pair moves towards the metaphase plate (where they line up before anaphase).By the end of this section, you will be able to: Centrosomes move to opposite ends of the cell, and the nuclear envelope dissolves.ħ.

This formation occurs because of sister chromatid cohesion, where a gene that has been given to the homologous pair in synapsis is still bonded to the corresponding part on the sister chromatid of its former chromatid.Ħ. Some of these homologs have one or more chiasmata, an X shaped region where a genetic rearrangement has occurred. Synapsis ends, and the homologs move slightly apart, no longer bonded along their lengths like in the synaptonemal complex.ĥ. This forms a synaptonemal complex.ģ.The random rearrangement of corresponding genes occurs between the non sister chromatids (because at this stage each chromosome consists of two sister chromatids).Ĥ. The paired homologs become physically connected along their lengths through a process called synapsis. Chromosomes condense and homologs loosely pair along their lengths, aligned by gene.Ģ. The above is also how a 46 chromosome (double strand) cell in mitosis can result in 2 daughter cells each with 46 chromosomes (single strand).Įven Sal admits how confusing this is, but he explains all this visually in a separate video differentiating the terms chromatid, chromosome, and chromatin.ġ. So a haploid parent cell of 23 chromosomes (double strand) just created two haploid daughter cells of 23 chromosomes (now single strand). When the chromatids are separated they are now called chromosomes Anaphase II splits the sister chromatids which now separate (23 chromatids go to one pole and 23 chromatids go to other pole). The parent cell starts with 23 chromosomes (EACH double stranded=two sister chromatids, so there are 46 chromatids. This means that in meoisis II when we split the sister chromatids: It is only when the sister chromatids separate are they each considered separate chromosomes. The single strand chromosome (1 chromosome) became two stranded yet attached identical sister chromatids (still 1 chromosome) Likewise chromosome 5 of dad is similar to chromosome 5 of mom)Īfter replication how many chromosomes do we have?

#Prophase 1 diagram code

In interphase before S (replication phase) we have 46 single stranded chromosomes: 23 are from mom and 23 are from dad (they code for the same things meaning chromosome 1 of mom codes for the same thing as chromosome 1 of dad. Remember that when replicating in interphase, the chromosome number DOES NOT CHANGE