Cells and control

• Stages of mitosis

  1. Interphase
  2. Prophase
  3. Metaphase
  4. Anaphase
  5. Telophase
  6. Cytokinesis
• Interphase


  The cell needs to grow and increase its subcellular structures and duplicate DNA. When the DNA copies it forms into X-shaped chromosomes, with each arm being the exact same as the other.
• Prophase


  The chromosomes condense and the nucleus membrane breaks down and the chromosomes lie free in the cytoplasm of the cell
• Metaphase


  Chromosomes line up in the middle of the cell
• Anaphase


  Spindle fibres pull the chromosomes apart, and then the chromatids are pulled to opposite ends of the cell.
• Telophase


  Membranes form around the two sets of chromosomes

  . This becomes the nuclei of two new cells
• Cytokinesis


  The cytoplasm and cell membrane split to become two seperate daughter cells
• Mitosis is important because it ensures our cells can:

  -Grow and survive

  -Repair broken cells

  -Reproduce in asexual reproduction
• Mitosis is the division of a cell into two daughter cells with identical sets of chromosomes from the parent cell. This means they are genetically identical diploid cells.
• Cancer is when there is a change in one of the genes that controls cell division causing the cell to start dividing uncontrollably. This can result in a mass of abnormal cells called a tumour- if this invades surrounding tissue it is called cancer
• Cell division and differentiation in animals

  When we are young, cells divide at a fast rate however when we are older most cell division is for repair. Cell differentiation is also lost at an early stage.
• Cell division, differentiation, and elongation in plants

  Growth in height in plants is cell elongation (where a plant cell cell expands). The cell division happens at the meristems, where unspecialised cells are produced to divide into any type of cell type- this is mainly the xylem and phloem. Plants continue to differentiate to develop new parts to grow.
• Cell differentiation + specialised cells

  Cell differentiation is important because it changes cells to be specialised cells fitted to do a particular job meaning a multicellular organism can work more effectively
• What is a percentile chart?

  A graph used to assess a childs growth over time so that an overall pattern of development can be seen and any problems highlighted. The results are plotted on a percentile chart- for example, the 50th percentile will be 50%
• Embryonic stem cells


  Scientists experiment with extracting stem cells from early human embryos and growing them. In certain circumstances these cells can differentiate into specialised cells and these cells can be used to replace those damaged by disease or injury e.g muscle cells for those with heart disease
• Stem cells


  Stem cells are undifferentiated cells. They can divide by mitosis to become new cells which can then differentiate. They can be found in early human embryos, bone marrow, and meristems. They are important for the growth and development of organisms.
• In animals, adult stem cells (found in bone marrow) are used to replace damaged cells and can only differentiate into certain types of cell
• Benefits and Risks of using stem cells in medicine

  Benefits- potential for new cures, able to replace any damaged cells

  Risks- Tumor development from dividing too quickly, disease transmission from donor, rejection of cells