3.18b - genotype

- phenotype is controlled by the genotype
- genotype is a combination of 2 allels
- allel key - R = red  r = white

3.18a - phenotypes

- same species
- phenotype is what we can see i.e. red petal flower, white petal flower
- red petal x red petal = red petal
- white petal x white petal = white petal
- red petal x white petal = red petal
- red petal - dominant
- white petal - recessive

3.2 - fertitlisation

- fertilisation produces a zygot which turns into an embryo
- during meiosis the diploid number in a male and female will half (36)
- during sexual reproduction, these fuse together which then forms one cell - this is fertilisation and called a zygot
- the cell goes through mitosis, the cells divide all with a 2n diploid number (46) - this develops into an embryo

3.10 - menstrual cycle

- oestrogen and progesterone are both hormones
- endrocrine gland - hormones through the blood - target tissue (effect)
- ovary is the endrocrine gland for oestrogen
- in the first half of the cycle, the lining of the uturus becomes increasingly thick, this is the effect of oestrogen
- oestrogen flows through the blood to our brain which releases a second hormone called lutenising hormone
- at day 13, this will release an egg
- the folical which once held the egg now produces progestrone
- the progestrone then prevents the lining of the uturus from breaking down
- if the egg is not fertilised then this leds to the break down of the lining which causes menstrual periods

2.9b - female reproductive system

- ovary produces the eggs
- oviducts carry eggs to the uterus, and fertilization takes place
- uterus wall is a muscle

- lining of uterus developes the fertilized egg and turns into the embryo 

- cervix is the entrance to the uterus 

- uterus space is where the embryo developes 

- vagina collects sperm cells from the penis 

3.9a male reproduction system

- bladder stores urine
- testis produce sperm through meiosis
- epididymis is where the sperm is stored in the testis
- vas deferens is the tube which carries sperm cells to the penis
- prostate adds 20-30% of the semen
- seminal vesticals produce 70% of the semen
- urethra is the tube which connects the testis and SV, takes semen to the penis
- penis carries sperm into vagina

3.12 - amniotic fluid

- in the space of the embryo is the aminiotic fluid
- this fluid cannot be compressed and it absorbs pressure
- fluid causes floating because the childs bones cannot support them yet as they are not hard
- this means with any blows to the outside uterus it will prevent damage to the unborn child