fertilisation

• fertilisation - fusion of gamete nuclei to form a zygote
• label

  A) sperm

  B) chemical

  C) cervix

  D) uterus

  E) oviduct

  F) egg

  G) nucleus

  H) cytoplasm

  I) membrane

  J) jelly coating

  K) tails

  L) head

  M) 23

  
• label

  A) pollen

  B) pollen tube

  C) ovary

  D) wall

  E) fruit

  F) haploid

  G) ovule

  H) seed

  
• fertilisation in plants

  • ovary contains 1 or more ovules which develop into seeds
  • each ovule contains an ovum - egg cell that contains female nucleus that a male pollen nucleus can fuse with (fertilisation)
• pollen tube

  • pollen grain has no tail like animal sperm
  • instead, the pollen grows a pollen tube (only when landed on stigma of same species)
  • the nucleus inside the pollen grain moves down the tube as the tube grows down the style towards the ovary
• label

  A) micropyle

  B) micropyle

  
• seed and fruit

  • ovule -> seed
  • wall of ovule develops into a seed coat aka testa
  • ovary walls -> fruit
  • the fruit provides a mechanism of seed dispersal
  • some fruits are eaten by animals which disperse the seeds in their droppings
  • the tough outer coat of seeds stops them from being digested
  • other fruits have sticky hooks that get caught in the fur of animals
• note that pollination is when the pollen grains are transferred from the anther to the stigma whereas fertilisation is when the gamete nuclei fuse