1. National 5 Biology Unit 2 – Cell Biology
Section 9
Reproduction

2. We will be learning…
Explain that non-sex cells are diploid and gametes (sex cells) are haploid.
State that sperm are the male gametes in animals and that they are produced in the testes.
Describe the structure of sperm
State that eggs (ova) are the female sex cell in animals and that they are produced in ovaries.
State that eggs (ovules) are the female sex cell in plants and that they are produced in ovaries.
State that pollen is the male gametes in plants and that they are produced in the anther
State that fertilisation is the fusion of the nucleus of the male gamete with the nucleus of the female gamete resulting in a diploid cell called a zygote.

3. What is Reproduction? All living things reproduce.
Humans use sexual reproduction to produce their young.
In order to do this, the two parents (male and female) have different reproductive systems and organs that produce different sex cells.

4. Gametes - Haploid Cells
Eventually the adult will produce sex cells.
Another name for sex cells is Gamete.
Gametes only have one set of chromosomes.
A Haploid cell has only one set of chromosomes.

5. Male Gamete Sex Cells – Sperm
In males, the sex cells are called sperm.
tail
middle piece
head
The mitochondria in the middle section provide the energy for the sperm to reach the egg
cell membrane
nucleus containing DNA
Sperm are produced in sex organs called testes.

6. The Male Reproductive System

7. The Male Reproductive System
Name
Function
Testes
Sperm Duct
Penis
Urethra
Produces haploid sperm. This diploid structure is the site of gamete production in male animals.
Carries sperm from testes to penis
Becomes stiff and erect. It is inserted into the vagina during copulation (sexual intercourse)
Sperm leaves the body through the urethra.

8. nucleus containing DNA
Female Gamete Sex Cells – Egg
In females, the sex cells are called eggs.
nucleus containing DNA
cytoplasm
membrane
jelly coat
Eggs are produced in sex organs called ovaries.

9. The Female Reproductive System

10. The Female Reproductive System
Name
Function
Ovary
Oviduct
Uterus
Vagina
Produces haploid eggs. This diploid structure is the site of gamete production in female animals.
Carries eggs from ovary to uterus.
Fertilisation occurs here.
Embryo will implant here.
and will develop in a foetus.
Penis inserted here during copulation.

11. Sex Cells – Gametes Summary
Female
egg / ovum
does not move on its own
large
foodstore present
made in ovaries
Male
sperm
swims using tail
very small
no foodstore
made in testes

12. Diploid Cells
After fertilisation, a zygote (fertilised egg) is formed.
This cell is diploid.
A diploid cell has 2 sets of chromosomes.
One set has come from the male parent and one set has come from the female parent.

13. Roles of the Reproductive System

14. Ovulation and fertilisation
In a female, one of the ovaries produces an egg approximately every 28 days. This is called ovulation.
During sexual intercourse, millions of sperm are ejaculated into the vagina.
If a sperm meets the egg, the sperm’s nucleus can join with the egg’s nucleus.
The fusing of the two nuclei is called fertilisation.

15. Fertilisation

16. Sexual Intercourse and Fertilisation
(3) Egg divides in two
(2) Sperm fertilises egg
(5) Embryo implants in uterus and grows
(4) Ball of cells formed
(1) Egg released from ovary

17. The Sexual Cycle Diploid Cells Gamete Fertilisation Formation Haploid

18. Fertilisation and Embryonic Development
The moment of fertilisation.
30 hours
This zygote is no larger than the head of a pin.  
Still rapidly dividing the zygote floats down from the fallopian tube towards the uterus.
Once fertilised it is called a zygote, until it reaches the uterus 3-4 days later.

19. 1-2 DAYS
3 DAYS
WEEK 5
The zygote continues to divide until there are more and more cells.
This stage of the zygote is called the blastocyst.
The embryo’s tiny heart begins to beat by day twenty-one. The brain starts to develop.  
This is the blastocyst just before the moment of implantation into the uterus wall.

20. WEEK 7 WEEK 9-12 Major organs begin to form.
Hair and knees and elbows are visible. 
Facial features start to develop.  The eyes have a retina and lens. 
Muscles have started to develop and the embryo is able to move. 
Size is less than 1cm long.
Until the end of week 8 the baby is called an embryo.
The heart is almost completely developed and can be heard.  The eyes are almost fully developed.  Hands, fingers, feet, and toes are fully formed. 
Nails and earlobes start to form and tooth buds develop in the gums. 
Foetus can make a fist with its finger. 

21. WEEK 17
WEEK 20
WEEK 22
WEEK 13
The foetus can suck, swallow, and make irregular breathing sounds. 
It would be possible to feel pain. 
The skin is almost transparent. 
Bones become harder.   
Eyebrows and eyelashes appear.
The foetus makes active movements including kicks and even somersaults. 
Size is about 14cm.
The mother can feel the foetus moving. 
Finger and toenails appear. 
A fine hair now covers the entire body. 
The foetus can hear and recognize the mother’s voice. 
An ultrasound scan at 22 weeks.

22. WEEK 30-36 WEEK 38 WEEK 24 WEEK 26 Rapid brain development.
The fetus is full-term.  The hair remains on upper arms and shoulders.  Hair on the head is thicker.  The lungs are mature.  The average weight of the baby is seven and a half pounds and length is 50cm. 
The placenta detaches and the umbilical cord is cut as the baby takes the first breath of air.  Breathing triggers changes in the heart and forces all blood to now travel through the lungs.   
The foetus sleeps 90-95% of the day.
Your baby starts to get ready for birth by laying down fat and getting plumper.
Size is about cm long.
The baby has now turned and the head is pointing down, ready to get into the birth position.
A protective waxy substance called Vernix covers the skin.  By birth, most of the vernix will be gone.
Footprints and fingerprints are forming. 
Foetus practices breathing by inhaling amniotic fluid into its developing lungs. 
Rapid brain development.
The eyelids now open and close. 
The baby has a regular sleeping and waking pattern now and movements can be clearly felt.

23. Menstruation
An important part of puberty for girls is the beginning of their monthly cycle. This is known as the menstrual cycle.
The menstrual cycle involves the preparation of the uterus lining so that it can receive a fertilized egg.
If an egg is fertilized, it can implant itself in the prepared uterus lining.
If the egg is not fertilized, the lining of the uterus breaks down and is lost from the body. This is called menstruation, or a period.

24. Asexual Reproduction in plants
It is possible for plants to reproduce asexually i.e. without flowers or fertilisation.
It can occur naturally or as a result of propagation by growers
Sexual reproduction also occurs in plants
The FLOWER contains the both the male and female reproductive organs of a plant.
Flowers of different plants may not be exactly alike, but they are built to the same basic plan.

25. Asexual Reproduction
Asexual reproduction only needs one parent, unlike sexual reproduction, which needs two parents. Since there is only one parent, there is no fusion of gametes and no mixing of genetic information. As a result, the offspring are genetically identical to the parent and to each other: in other words, they are clones.
Runners

26. Sexual Reproduction in Plants
Is a form of reproduction that involves TWO PARENTS
Plants can reproduce sexually
Flowers are plants reproductive organs
They contain both MALE and FEMALE parts

27. Looking Inside a Flower

28. Nectary makes sugary liquid called nectar which insects eat
Petals
Stigma
Brightly coloured to attract insects
catches pollen grains
Style
Anther
pollen tube grows down through this
Male part where pollen is made
Ovary
Ovule
Where the female sex cells, ovule is made
becomes a seed when joined with pollen
Nectary makes sugary liquid called nectar which insects eat
Sepal
Protects the unopened flower

29. Male Parts of a Flower Anther makes pollen Stamen (male part)
Filament holds anther
Stamen (male part)

30. Female Parts of a Flower
Stigma where the pollen lands
Ovary produces ovules
ovules

32. Structure Function Sepal Petal Stamen Anther Stigma Ovary Nectaries
protect the unopened flower bud
Petal
may be brightly coloured to attract insects
Stamen
the male parts of the flower consisting of the anther held up on the filament
Anther
produce male sex cells (pollen grains).
Stigma
the top of the female part of the flower which collects pollen grains
Ovary
produces the female sex cells (ovules)
Nectaries
produce sugary nectar which attracts insects

33. Gamete Formation in Flowering Plants
Flowers are the organs of sexual reproduction in plants.
Usually the male and female reproductive organs are both present in the same flower.
Pollen grains contain the plant's male sex cells and are produced in the anthers. Ovules contain the plant's female sex cells and are produced in the ovary.

34. Insect Pollination
These plants often have flowers that are brightly coloured
and scented . The pollen from the anther sticks
to the insect’s body while it is sucking nectar from the
flower. The pollen gets brushed on to the style of the
flower.

35. Wind Pollination Feathery stigma
The wind blows the smooth pollen off the anther onto the feathery stigmas, which hang outside the flower so they can easily catch the pollen. As these plants don’t rely on insects, the petals are in colour.

37. Fertilisation
The zygote formed becomes an embryo which later grows into a plant containing genetic material from both the male and the female parents
Pollen grain
Stigma
Style
Pollen tube
Nucleus
Ovary
Ovule