Producing New Cells

Producing New Cells

1. Mitosis

   • Mitosis is the process of cell division to create two identical daughter cells
     • It is important that the daughter cells receive a full set of chromosomes so that they can function properly
   • In multicellular organisms, mitosis is vital for growth and repair
     • Humans have a chromosome compliment of 46.
       • Chromosome Compliment- The chromosome compliment is the DNA that contains genetic information. If a daughter cell doesn't receive a full chromosome compliment, the cell can not function properly.
       • It is important that the daughter cells maintain the same number of chromosomes as the parent because if they don't have the right number of chromosomes they can't function properly.
     • Cells in the human body are diploid. This means they have two full sets of chromosomes.

2. Stem Cells

   • Stem cells are cells that are unspecialised. They can become any cell in the body.
     • Unspecialised / undifferentiated cells- Cells that have not yet become a specific type of cell.
     • Stem cells are found in the bone marrow, the brain, and the umbilical chord of babies.

3. Stages of mitosis.

   • Stage 1- Nucleus contains long, uncoiled chromosomes
   • Stage 2- Chromosomes double to form two identical chromatids
   • Stage 3- Chromosomes (made up of two chromatids) line up at the equator. Spindle fibres form.
   • Stage 4- Chromatids are pulled apart to opposite ends (poles) of the cell.
   • Stage 5- Separated chromatids are now chromosomes. Cytoplasm divides. Nuclear membrane forms.
   • Stage 6- New cell forms and creates two identical daughter cells with the same number of chromosomes as the parent cell.

4. How Tissues are formed.

   • The specialisation of cells (from stem cells) leads to the formation of lots of different cells, tissues and organs.
     • This is the order of organs forming from stem cells.: Stem cells- specialised cells- tissues- organs- organ systems.

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