3.19 F1 x F1 Cross

PART A

PART B 

3.18 Phenotype and Genotype

Part A

Part B 

3.2 Fertilisation

• The process of fertilization begins with the adults male and female.
• The cells in testis and in ovaries have a complete cell of chromosomes                                                      - this is called diploid (2n) which is a complete set of chromosomes and for human it is 46
• The cells divide to form cells with half sets of chromosomes, this type of cell division is called meiosis  - > this makes the cell go from a diploid number to a haploid number(n) which is a 1/2 set so in humans it is 23 (there are 23 chromosomes in the sperm cell and 23 chromosomes in the egg cell)
• During sexual reproduction the two cells are brought together and joint/fused together, so forms 1 cell. This process is know as fertilization. Which involves the combining of half set of chromosomes and another half set of chromosomes to make a full set of chromosomes (n+n=2n/in humans 23+23=46)
• This cell is known as a zygote.
• We have a combination with a male and female chromosomes. This cell then goes through the process of cell division called mitosis, in which the cells will divide to get 2 cells, they will both contain 46 chromosomes. They will then divide. All cells contain 2n diploid number.
• When we have sufficient cells, this will then be called an embryo.
• This principle holds truth for all sexually reproducing organisms but the numbers are for human only

credits to Daniel :)

3.9 b) Structure and Function of a Female reproductive System

Ovary : where Meiosis occur and production of eggs

Oviducts : carry eggs to uterus  and where fertilsation occur in here.

Uterus : wall made from muscle - will stretch during pregnancy and contract during giving birth

Lining of uterus : Accept and develop the fertilise eggs which will be develop here to embryo -> child
                         - Development of placenta

Uterus space: - Embryo develop to unborn child
                      - Both sperm cells and egg cells move

Cervix: entrance to uterus

Vagina : Collect the sperm cells and allow them into the cervix
             - Penis is introduced here

3. 9 a) Structure and function of Male reproductive system

Bladder : Store Urine

Testis : To carry out the process meiosis -> produce gamete = sperm cell

Epididymis: Store sperm cells

Vas deferens : Carry sperm sell to penis during sexual stimulation

Prostate : Contains 20%-30% volume of semen and is known to carry sugars and is alkali

               - The alkali is to neutralize the acidic secretion of the vagina

Seminal Vesicles : produce sugar based alkaline substances and contain 70% volume of semen

Urethra : Common tube which join the left and right testis and Vas deferens

               - Carry Semen and Urine down to Penis

Penis: Carry sperm cells into Vagina during sexual intercourse

3.12 Amniotic fluid

-Surrounding the uterus space is the amniotic fluid where it can protect the embryo


-This is because the fluid which is largely water can not be compressed. If we squeeze the fluid, it absorbs the pressure. 


- Any force applied to the uterus wall will absorb the pressure and prevent damage to the unborn child.

3.11 Placenta

Role of Placenta

-  When the child is in the uteris, they cannot digest or breath or excrete. The child obtain nutrition by the umbilical cord of the placental structure growing out of the embryo. 


- The blood vessel inside the placenta are the child blood's vessel include arteries and veins.


-  The placenta grows into the wall of the Uterus of the mother. During pregnancy, the mother continues to eat which means that there will be amino acids, glucose and fats in the blood which will cross through into the childs blood at the placenta then taken into the child. 


- To make this efficient, the Placenta have a large surface and a thin barriers


- The baby then produces molecules back to the mother, which is things like carbon dioxide and urea.