Cell division

• The nucleus in a cell contains the genetic material in the form of chromosomes.
• Each chromosome carries a large number of genes. different genes control different characteristics, eg hair colour
• Body cells have two copies of each chromosome one from the mother and one from the father
• Body cells in multicellular organisms divide to produce new cells as a part of a series of stages called the cell cycle
• Mitosis is the stage of the cell cycle when the cell divides
• Multicellular organisms are organisms that have more than one cell.
• Multicellular organisms use mitosis to grow and replace cells that have been damaged
• The end of the cell cycle results in two new cells identical to the original cell, with the same number of chromosomes
• There are two main stages of the cell cycle : the growth and DNA replication and mitosis
• Interphase - The first phase of the cell cycle where the cell grows and duplicates its DNA ready for division
• In a cell that’s not dividing the DNA is all spread out in long springs
• Before the cell divides, the cell is to grow and increase the amount of sub-cellular structures such as mitochondria and ribosomes
• The cell will duplicate its DNA so there is one copy for each new cell. The DNA is copied in X-shaped chromosomes. Each arm of the chromosome is an exact copy
• Chromosomes are coiled up lengths of DNA
• Mitosis: a cell division that results in two daughter cells each with the same number and type of chromosomes as the parent
• DNA replicaion is the process of making new DNA molecules from the original DNA molecule
• Growth of a cell is where the cell grows in size and number of organelles
• DNA are long molecules that form with a twisted double helix
• DNA is made up of many short sections called genes
• chromosomes are inside the nucleus of cells
• 23 pairs of chromosomes are arranged inside the nucleus
• mitosis is cell division from one cell to 2 identical daughter cells
• Interphase is where DNA is replicated then grows in size, increasing the number cellular structures
• There are three stages of mitosis

  • Cells are pulled apart to opposite sides of the cell
  • Cell membrane and cytoplasm divides
  • Two identical daughter cells are formed
• Stem cells are undifferentiated cells that can produce different cell types through differentiation
• Embryotic stem cells can differentiate into nearly any type of animal cell
• adult stem cells come from and bone marrow can differentiate into some types of animal cells
• Therapeutic cloning can be used to produce embryonic, genetically identical to the patient