1. Haileybury IGCSE Biology
REPRODUCTION
Haileybury IGCSE Biology

2. Learning objectives Distinguish between somatic cells and gametes
Outline the process of fertilisation
Compare internal and external fertilisation
Draw and label the male and female reproductive systems

3. Somatic Cells Most of the cells in our bodies are SOMATIC cells
They contain two sets of chromosomes
We describe it as being DIPLOID
One set from each parent
Our cells contain 46 chromosomes
23 from each parent

4. Gametes Sex cells are called gametes
They contain one set of chromosome
Our gametes contain 23 chromosomes
They will be a mixture of chromosomes from each parent

5. Gametes
Male
Female
Plants
Animals
Pollen
Ova
Sperm
Ovum

6. Fertilisation gamete gamete Somatic cell
Gametes are produced by meiosis
Meiosis is a type of cell division that halves the chromosome number
Fertilisation is a fusion of gametes
This restores the chromosome number

7. External fertilisation
Suitable for animals that mate in water
Many eggs
The sperm are able to swim through the water to fertilise the eggs
The eggs do not have shells

8. Internal fertilisation
Suitable for animals that mate on land
Few eggs
The sperm are placed inside the female
The eggs have shells

9. External vs Internal External Internal Where is it used?
Soft eggs or eggs with shells?
Many or a few eggs
example

10. Reproduction
Learning objectives
Distinguish between asexual and sexual reproduction and give example of both
Draw and label the structure of the human male and female reproductive systems
State the functions of the organs of the male and female reproductive systems

11. ASEXUAL REPRODUCTION
Asexual reproduction requires just one parent and does not involve the production of gametes

12. Can human’s reproduce asexually?

13. SEXUAL REPRODUCTION
Sexual reproduction requires two parents and the production of GAMETES

14. Male Reproductive System
Part
Function
Penis
Placement of sperm into the vagina
Testes
Production of sperm
Seminal vesicles
Adds fluid to the sperm
Prostate
Sperm duct
Transports sperm to the urethra
Urethra
Transports sperm to the end of the penis during (ejaculation)
Sperm duct

15. Male Reproductive System
Draw and label the diagram above

16. Male Reproductive System
Part
Function
Placement of sperm into the vagina
Testes
Adds fluid to the sperm
Prostate
Transports sperm to the urethra (during ejaculation)
Transports sperm to the end of the penis (during ejaculation)
Penis
Testis (pl. testes)
Sperm duct

17. Sperm cell

18. Female reproductive system
Oviduct
Ovary
Part
Function
Oviduct
Transport of the ova and the site of fertilisation
Ovaries
Where ova are stored and released
Cervix
The entrance to the uterus
Vagina
Receives the sperm during sexual intercourse
Uterus
Also known as the womb – where the foetus develops
Ovary

19. Female Reproductive System
Draw and label the diagram above

20. Female reproductive system
Part
Function
Transport of the ova and the site of fertilisation
Ovaries
The entrance to the uterus
Vagina
Also known as the womb – where the foetus develops

21. Ovum

22. Sexual Intercourse
The biological purpose of sexual intercourse is to place the sperm as close as possible to the ovum to optimise the chance of fertilisation.
The ovum is wafted down the fallopian tubes (oviducts) by small hairs called cilia.
The sperm have to swim through the cervix, uterus and part of the way up the fallopian tubes.
Only a very small proportion of the sperm will reach the ovum.
Barrier methods of contraception such as condoms prevent the sperm from reaching the ovum

23. Fertilisation
The membrane of the head of the sperm fuses with that of the ovum.
Changes to the zona pallucida prevents the entry of another sperm.
The male nucleus containing 23 chromosomes fuses with the female nucleus which also contains 23 chromosomes.
The fertilised ovum is now called a zygote and it contains 46 chromosomes.
Half the sperm contain a Y chromosome, resulting in a boy and the other half contain an X chromosome resulting in a girl.

24. Fertilisation to Implantation

25. Questions Where does fertilisation occur? Define the following words:
Zygote
Blastocyst
Fertilisation