1. Haileybury IGCSE Biology
REPRODUCTION
Haileybury IGCSE Biology

2. 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

3. 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

4. Gametes
Male
Female
Plants
Animals
Pollen
Ova
Sperm
Ovum

5. 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

6. Flower Structure

7. Copy the drawing and complete the table

8. Pollination

9. Pollination
Pollination is the transfer of pollen from the STAMEN of one flower to the STIGMA of another.

10. Male Reproductive System
Parts not labelled on the diagram
Part
Function
Cowper’s gland
Releases fluids prior to ejaculation
Epididymis
Stores the sperm
Erectile tissue
Fills with blood during an erection
The testicle is better labelled as testis pl. testes. The plural of vas deferens is vasa deferentia.
(vas deferens)

11. Male Reproductive System
Draw and label the diagram above

12. Sperm cell

13. Female reproductive system
Parts not labelled on the diagram
Part
Function
Fallopian tubes
Transport of the ova and the site of fertilisation
Ovaries
Where ova are stored and released
Cervix
The entrance to the uterus

14. Female Reproductive System
Draw and label the diagram above

15. Ovum

16. 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

17. 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.

18. Fertilisation to Implantation

19. Questions Where does fertilisation occur? Define the following words:
Zygote
Blastocyst
Fertilisation
How does the ball of cells travel towards the nucleus?
Why is it important that it does not take any longer for the blastocyst to implant in the wall of the nucleus?

20. Hormonal control of the menstrual cycle
FSH causes the ripening of (usually one) Graafian follicle.
The follicle produces oestrogen that thickens the lining of the uterus.
LH release results in ovulation and production of the corpus luteum.
The corpus luteum produces progesterone that maintains the uterine wall.
FSH and LH are used in fertility treatment.
Oestrogen and progesterone are used in the contraceptive pill.

21. Hormonal control of the menstrual cycle
____ causes the ripening of (usually one) Graafian follicle.
The follicle produces ______ that thickens the lining of the uterus.
_____ release results in ovulation and production of the corpus luteum.
The corpus luteum produces ________ that maintains the uterine wall.
FSH and LH are used in _____ treatment.
Oestrogen and progesterone are used in the ________ pill.
Progesterone LH
Contraceptive
Fertility
Oestrogen
FSH

22. Placenta & Amnion

23. Learning Objectives State the functions of the amnion
Outline the functions of the placenta

24. Amnion
The amnion is a membrane surrounding the foetus. It contains the amniotic fluid. It provides a moist environment and protection from bumps. It ruptures at the onset of birth and the amniotic fluid is released.

25. The placenta Produces the hormone HCG that leads to morning sickness.
Produces Progesterone that maintains the uterine wall.
Provides nutrients and oxygen.
Removed urea and carbon dioxide.
Maternal and foetal blood come close together but do not mix

26. A closer look….
Chorionic villi increase the surface area for the exchange of substances.
Substances pass across the placenta by diffusion.
The placental membrane acts as a barrier to pathogens (disease).
Antibodies do not pass across the membrane so the first milk or colostrum is important.
Alcohol and drugs can pass across the placental membrane

27. Video clip – An Everyday Miracle
A quick look at the placenta!
Then: Cambridge IGCSE Combined and Coordinated Sciences page 143 Questions 2&3. You are required to draw any diagrams!