cell division

• how is DNA stored in the nucleus?

  In the nucleus of each cell, the DNA molecule is packaged into thread-like structures called chromosomes. Each chromosome is made up of DNA tightly coiled many times around proteins called histones that support its structure.
• what are genes?


  Segments of DNA that contain instructions for building and maintaining an organism. A gene is a section of DNA which controls part of a cell's chemistry - particularly protein production
• what is the cell cycle?

  • The cell cycle is a set of steps that take place in cell division.The cell cycle is how cells duplicate and divide. Cells need to divide all the time to replace dead cells, for growth and for repair.
• the process of mitosis

  1. Interphase – the cell gets ready to divide. The cell grows, DNA duplicates and more organelles are made.
  2. Mitosis – the genetic material separates to different ends of the cell, and the cell gets ready to divide into two daughter cells.
  3. Cytokinesis – at the end of mitosis, the cytoplasm and cell membrane split, and two new daughter cells are made.
• where does mitosis occur?


  Mitosis occurs in all eukaryotic cells. in the nucleus
• what are stem cells?

  Undifferentiated cells that have the potential to develop into various types of specialized cells in the body. They serve as a repair system for the body. There are two main types of stem cells: embryonic stem cells and adult stem cells.
• where are stem cells in the body?

  Bone marrow and umbilical cord blood contain hematopoietic stem cells (HSCs) and non-hematopoietic or mesenchymal stem cells (MSC), the latter residing also in numerous other tissues. These cells are multipotent because they can differentiate into specific body cell types.
• where are stem cells in plants?

  Stem cells are found in plant meristems. Stem cells in plant meristems can differentiate to form any type of plant cell. They are present throughout the lifespan of the plant.
• how can meristems be used for cloning?

  Meristems are regions of undifferentiated cells typically found near the tips of stems and roots. These cells are capable of division and growth. Meristem tissue cuttings can be used to produce clones of plants quickly and economically.
• how are stem cells used for therapeutic cloning? (in animals)

  One example is to use a person's DNA to clone one of their organs for use in transplanting. could produce stem cells with the same genetic make-up as the patient. The technique involves the transfer of the nucleus from a body cell of the patient, to a human donor egg cell.
• what are the risks of using stem cells in medicine?

  Mutations have been observed in stem cells cultured for a number of generations, and some mutated stem cells have been observed to behave like cancer cells. Cultured stem cells could be contaminated with viruses which would be transferred to a patient.
• how can using stem cells be beneficial?

  Stem cells can be guided into becoming specific cells that can be used in people to regenerate and repair tissues that have been damaged or affected by disease. People who might benefit from stem cell therapies include those with leukemia, Hodgkin disease, non-Hodgkin lymphoma and some solid tumor cancers.
• what are the issues surrounding stem cell use?

  There is no guarantee of how successful these therapies will be, for example in the use of stem cells in healing damage caused by Parkinson's disease. The difficulty in finding suitable stem cell donors. The difficulty in obtaining and storing a patient's embryonic stem cells.