Biology

Cards (38)

  • Disappears in metaphase and reforms in telophase.
  • Mitosis is the process by which the nucleus divides into two daughter nuclei each with the same number of chromosomes as the parent nucleus, maintaining genetic stability.
  • The nuclei formed in mitosis are genetically identical to the parent one, maintaining genetic stability.
  • Cells do not divide continuously, but undergo a regular cycle of division separated by periods of cell growth, known as the cell cycle.
  • The cell cycle consists of three stages: Interphase, Mitosis, and Cytokinesis.
  • Interphase occupies about 95% of the cell cycle and is a period of intense chemical activity divided into three parts: First growth (G1) phase, when the proteins from which cell organelles are synthesised are produced; Synthesis (S) phase, when DNA is replicated; Second growth (G2) phase, when organelles grow and divide and energy stores are increased.
  • Mitosis is the stage in the cell cycle when the nucleus divides into two.
  • Cytokinesis is the stage in the cell cycle when the cytoplasm of the cell divides into two.
  • The rate of cell division is controlled by proto-oncogenes that stimulate cell division and tumour suppressor genes that slow cell division.
  • The longest phase in the cell cycle of human liver cells is interphase.
  • Mitosis is the basis for the production of new individuals of a species by only one parent.
  • During mitosis, a cell divides into two daughter cells, both of which are genetically identical.
  • Chromatids break apart at the centromere and are pulled away by microtubules towards the poles during mitosis.
  • In animal cells, cytokinesis after mitosis is achieved by the growth of the cell plate at the equator from the centre outwards.
  • Animal cells undergoing mitosis have a centriole, but plant cells undergoing mitosis do not.
  • In root tip cells, cell plate formation occurs during anaphase.
  • The stages of mitosis are: prophase, metaphase, anaphase, telophase, and cytoplasmic cleavage.
  • Mitosis does not allow for the growth of multicellular organisms from unicellular zygotes.
  • Mitosis is used to replace identical cells and repair tissues in both plants and animals.
  • If a proto-oncogene becomes mutated it is called an oncogene and it stimulates cells to divide uncontrollably.
  • Mitosis ensures the independent assortment of homologous chromosomes.
  • During mitosis, the nucleolus disappears in prophase and reforms in anaphase.
  • If a tumour suppressor gene mutates it becomes inactive, allowing the rate of cell division to increase.
  • Cells that start to divide uncontrollably are often removed by the immune system; if not they may grow into tumours such as benign and malignant cancers.
  • The genetic information (DNA) of cells is packaged into chromosomes.
  • When chromosomes are visible, they appear as long, thin threads around 50μm long, made up of two strands called chromatids, joined at a point called the centromere.
  • The centromere is a constricted region of the chromosome containing a specific DNA sequence, to which is bound two discs of protein called kinetochores.
  • Centrioles organise the formation of the spindle in animal cells.
  • Centrioles are found only in animal cells and a pair of centrioles are found within a centrosome.
  • Chromosome numbers vary across species, with some protozoa having 300 chromosomes.
  • In animal cells, cytokinesis involves the formation of a
  • In animal cells, centrioles organise the formation of the spindle.
  • In plant cells, there is no cleavage furrow, instead vesicles derived from the Golgi apparatus move to the middle of the cell where they join together to form a cell plate.
  • Metaphase chromosome, Kinetochore, microtubules, Centromere, region of chromosome, Sister Chromatids, pronunciation, Kinetochore (Key - neto - chore)
  • In plant cells, there are no centrioles, hence no centrioles organise the formation of the spindle.
  • Kinetochores serve as points of attachment for microtubules that move the chromosomes during cell division.
  • In animal cells, cytokinesis involves the formation of a cleavage furrow which pinches the cell in two.
  • The cell plate enlarges until its surrounding membrane fuses with the plasma membrane along the perimeter of the cell thus forming two daughter cells.