three sisters

Examples of three sisters in the following topics:

• Living Mammals

  • Living mammals can be classified in three subclasses: eutherian, metatherians and monotremes.
  • Living mammals can be classified into three major classes: eutherians, monotremes, and metatherians.
  • Monotremes form their sister clade.
  • There are three living species of monotremes: the platypus and two species of echidnas, or spiny anteaters.
  • Name and describe the distinguishing features of the three main groups of mammals

• Meiosis I

  • Meiosis is preceded by an interphase consisting of three stages.
  • A single crossover event between homologous non-sister chromatids leads to an exchange of DNA between chromosomes .
  • The sister chromatids remain tightly bound together at the centromere.
  • Although there is only one chromosome set, each homolog still consists of two sister chromatids.
  • Crossover occurs between non-sister chromatids of homologous chromosomes.

• MLA: Block Quotations

  • In MLA style, format quotations of more than lines of prose or more than three lines of verse as block quotations.
  • However, if you want to quote more than four lines of prose (or three lines of verse) from a source, you should format the excerpt as a block quotation, rather than as a regular quotation within the text of a paragraph.
  • Alice was beginning to get very tired of sitting by her sister on the bank, and of having nothing to do: once or twice she had peeped into the book her sister was reading, but it had no pictures or conversations in it, 'and what is the use of a book,' thought Alice, 'without pictures or conversations?’
  • If quoting more than three lines of verse, maintain the original line breaks.

• Regulation of the Cell Cycle at Internal Checkpoints

  • The cell cycle is controlled by three internal checkpoints that evaluate the condition of the genetic information.
  • To prevent a compromised cell from continuing to divide, internal control mechanisms operate at three main cell cycle checkpoints.
  • The M checkpoint is also known as the spindle checkpoint because it determines whether all the sister chromatids are correctly attached to the spindle microtubules.
  • Because the separation of the sister chromatids during anaphase is an irreversible step, the cycle will not proceed until the kinetochores of each pair of sister chromatids are firmly anchored to at least two spindle fibers arising from opposite poles of the cell.
  • The cell cycle is controlled at three checkpoints.

• Optional Collaborative Classrom Exercise

  • In your class, have someone conduct a survey of the number of siblings (brothers and sisters) each student has.Create a frequency table.Add to it a relative frequency column and a cumulative relative frequency column.Answer the following questions:
  • True or False: Three percent of the people surveyed commute 3 miles.If the statement is not correct, what should it be?

• Phylogenetic Trees

  • Notice in the rooted phylogenetic tree that the three domains (Bacteria, Archaea, and Eukarya) diverge from a single point and branch off.
  • When two lineages stem from the same branch point, they are called sister taxa.
  • It is important to note that although sister taxa and polytomy do share an ancestor, it does not mean that the groups of organisms split or evolved from each other.
  • Both of these phylogenetic trees shows the relationship of the three domains of life (Bacteria, Archaea, and Eukarya), but the (a) rooted tree attempts to identify when various species diverged from a common ancestor, while the (b) unrooted tree does not.
  • When two lineages stem from the same branch point, they are sister taxa.

• Leukemia

  • She later provided bone marrow for a transplant for her older sister.
  • The younger sister, now in her 20s, is happy that she was able to save the life of her older sister, who was dying in 1990, but has now had two decades and counting of a healthy life thanks to her ‘baby' sister.
  • As of August 2011, a year after treatment, two of the three patients are cancer-free.

• Meiosis II

  • During meiosis II, the sister chromatids within the two daughter cells separate, forming four new haploid gametes.
  • The sister chromatids are maximally condensed and aligned at the equator of the cell.
  • The sister chromatids are pulled apart by the kinetochore microtubules and move toward opposite poles.
  • In prometaphase II, microtubules attach to the kinetochores of sister chromatids, and the sister chromatids are arranged at the midpoint of the cells in metaphase II.
  • In anaphase II, the sister chromatids are separated.

• Interphase

  • The three stages of interphase are called G1, S, and G2 .
  • In the S phase, DNA replication results in the formation of identical pairs of DNA molecules, sister chromatids, that are firmly attached to the centromeric region.

• Superphylum Ecdysozoa

  • Others have suggested that a possible solution is to regard Ecdysozoa as a sister-group of Annelida, though many scientists consider them unrelated.
  • There were three types, or grades, of organization: the Acoelomata (no coelom), the Pseudocoelomata (partial coelom), and the Eucoelomata (true coelom).