Wednesday, June 10, 2009

Lesson 10: Cell division-mitosis and meiosis

Hi,

This is a very good revision material to view. concepts covered include:
  • cells divide to increase numbers for growth, repair and reproduction
  • cell organelles-mitochondria, chloroplast, nucleus, cell membrane
  • specialised cells-red blood cell, nerve cell, pollen, guard cell, palisade cell, xylem cell,
  • 1 billion cells per hour are replaced in your body by cell division
  • blood cells by bone marrow by mitosis
  • skin cells 100 million per day by mitosis
  • zygote, 1 cell, grows into baby within 9 months by mitosis
  • photographs on mitosis in onion shoot and root tip showing mitosis
  • meiosis- in testis, ovary, anther
  • fertilisation restores the diploid number in zygote
  • mitosis ( 2n--> 4n--> 2n-->2n)
  • meiosis (2n--> 4n-->2n-->n)
  • the sex of child is determined at the point of fertilisation
  • fertilisation with y-carrying sperm results in male, fertilisation with x-carrying sperm results in female child.
  • meiosis occurs in anther producing pollen, in testis producing sperm, in ovary producing ova, ( or ovule in plant).
  • self fertilisation less variation than cross fertilisation in plants
  • short questions



Cheers

2 comments: