cell divsion

• what are chromosomes made up of?

  consists of DNA molecules combined with proteins
• what is a gene?


  a segment of DNA which codes for a protein
• how many chromosomes are found in the nucleus of human body cells?


  46 chromosomes
• how many chromosomes are found in the nucleus of gametes?

  23 chromosomes
• whats a gamete?


  Sex cell
• how are chromosomes arranged in the nucleus of a body cell?


  arranged in pairs
• what are the 3 main stages of a cell cycle?

  • replication of DNA and synthesis of organelles
  • mitosis
  • division of cell
• why is mitosis important?


  • produces indentical daughter cells which all have the same genetic information
  • produces additional cells for growth and repair
• what is the first stage of the cell cycle


  the longest stage

  • cells grow and increase in mass
  • replicate the DNA and synthesise more organelles
• what is the second stage of the cell cycle?


  • each chromosome in a pair is pulled to opposite poles of the cell
  • then the nucleus divides
• what is the third stage of the cell cycle?

  • the cytoplasm and cell membrane divide
  • two identical daughter cells are produced