1. Structure and Function
Gametes
Structure and Function

2. Human Ovum

3. Human Sperm

4. How are they adapted? Ova Sperm Smaller cell Sperm has a long tail
Large cell
Cytoplasm contains large amounts of protein and lipid food reserves
Surrounding egg jelly like coating called zona pellucida
Releases chemicals after a sperm fuses with membrane
Cannot move independently
Chemicals released
Smaller cell
Sperm has a long tail
Has large numbers of mitochondria present
Has an acrosome in the head which contains digestive enzymes

5. How are they adapted? Ova USE? Large cell
Cytoplasm contains large amounts of protein and lipid food reserves
Surrounding egg jelly like coating called zona pellucida
Releases chemicals after a sperm fuses with membrane
Cannot move independently
Chemicals released
Contains sufficient resources for early development of embryo
Thickens and prevents any further sperm entering egg
Wafted by cilia lining oviduct so directed where to move
To attract sperm

6. Uses of adaptations Sperm USE? Smaller cell Sperm has a long tail
Has large numbers of mitochondria present
Has an acrosome in the head which contains digestive enzymes
Move quickly, take sup less space
To enable it to move through cervix and uterus
To provide energy for tail
Breaks down the zona pellucida

7. Differences between sperm and ova
The ovum is much larger than the sperm – the ovum cytoplasm contains protein and lipid food reserves for the early development of the embryo; the small sperm can move easily.
The ovum has jelly-like coating; the sperm has no such coating – the ovum coating thickens after the first sperm penetrates, preventing entry of other sperm.
The sperm has a tail; the ovum has no tail – this allows the sperm to move through the cervix and uterus to reach the ovum in the Fallopian tube.
Sperm have an acrosome (a specialised lysosome); ova do not – this allows sperm to release digestive enzymes which break down the jelly-like coating of the ovum enabling the sperm to penetrate it.

8. Fertilisation