Sperm & Egg Cells
Biology: Cambridge International GCSE Supplement, topic 2.1.12
Sperm Cell
Sperm cells are specialised (can perform a specific function). Sperm cells are specialised to fertilise egg cells. To do this, they need to travel long distances relatively to their size. They then break through to the egg cell and fertilise it (combine the sperm DNA with the egg DNA).
Head
- The ‘head’ contains the sperm cell’s nucleus. The nucleus carries one half of an organism’s genetic material.
- This combines with the egg cell's half of genetic material to fertilise the egg cell.
Acrosome
- The acrosome at the tip of the head contains an enzyme needed to penetrate (break into) an egg cell.
Middle section
- The middle section is filled with mitochondria to provide the sperm with the energy it needs to travel a long distance to reach the egg cell.
Flagellum
- The flagellum is used for the cell’s motion. This allows sperm cells to travel towards the egg cell.
Egg Cell
The egg cell is fertilised by a sperm cell to become a zygote (which grows into an embryo). An egg cell is much larger than a sperm cell and it is specialised to support the zygote as it grows.
Haploid nucleus
- The nucleus contains half the genetic information needed for the new zygote.
- The sperm cell provides the other half.
Cytoplasm
- The cell is large and contains lots of cytoplasm, which is packed full of nutrients that the zygote will need to grow.
Jelly coat
- The jelly coat is adapted to harden once the egg is fertilised so that no more sperm can get into the egg cell.
Test yourself on Sperm & Egg Cells
What do sperm and egg cells have in common?
What is correct about sperm and egg cells?
Which of these statements correctly compares sperm cells and egg cells?