7 GROWTH + REPRODUCTION Flashcards
Products of mitosis
2 genetically identical diploid daughter cells
How many cell divisions in mitosis
1
How many cell divisions in meiosis
2
Products of meiosis
Produces 4 genetically non-identical haploid daughter cells (gamates)
Reasons for mitosis
Growth, repair and asexual reproduction
How many chromosomes in a haploid cell
23
How many chromosomes in a diploid cell
46
How does random fertilisation cause genetic variation
- Each ejaculate contains millions of sperm cells which are each genetically different due to meiosis
- Each female egg cell will be gentically different due to meiosis
- Which sperm fertilises the egg is random
How does fertilisation cause an embryo
a male and female gamete fuse to produce a zygote that undergoes mitosis to develop into an embryo
Use of ovary
Egg cells are formed and produces progesterone and oestrogen
Use of oviduct
Egg travels to uterus - site of fertilisation
What in the oviduct move the egg through to the uterus
Cilia
Use of uterus
Embryo implants and the foetus develops
Use of cervix
Dilates during labour to allow the baby to be born
Use of vagina
Penis insertion for sexual intercourse and for the baby to be born
Use of testes
Sperm cells formed by meiosis and produces testosterone
Use of sperm duct
Sperm transport
Use of seminal vesicles
Release liquids into sperm duct which mixes with sperm to form semen
Use of penis
Transport urine and semen out of the body
Use of urethra
Removal of urine or semen
Function of amniotic fluid
- Prevent against mechanical shocks
- Prevent drying out
- Prevent temperature fluctuation (due to wter’s high specific heat capacity)
Use of the placenta
- Allow nutrients like glucose amino acids and oxygen to move from mother to embryo
- Allow metabolic wastes like caron dioxide and urea to pass from embryo to mother
- All happens by diffusion
Why doesn’t the blood of the mother and foetus mix
- Mothers blood is at a much higher blood pressure
- Mothers blood has white blood cells that would attack the foetus
Secondary sexual characteristics of men
- Voice breaks
- Production of sperm
- Facial, armpit, body and pubic hair growth
- Greater muscle development
- Growth and development of genitalia
- Mood swings
- Acne
Sexual secondary characteristics of women
- Voice deepens
- Menstrual cycle begins
- Pelvis broadens
- Armpit and pubic hair growth
- Muscle development
- Fat deposits on breasts, hips and thighs
- Growth and development of genitalia
- Mood swings
- Acne
Effect of FSH
- Follicle develops and ovum matures
- Follicle releases oestrogen
Effect of oestrogen
- Inhibits FSH production
- Stimulates LH productin
- Thickens uteral lining
Effect of LH
- Ovulation
- Inhibits oestorgen
Effect of LH
- Ovulation
- Inhibits oestrogen production
Effect of progesterone
- FSH and LH inhibited
- Thickness of uteral lining maintained
How do plants asexually reproduce by tubers
One plant can prouduce many tubers which can each grow many shoots to make new plants
How do plants asexually reproduce by tubers
One plant can prouduce many tubers which can each grow many shoots to make new plants
How can plants be artifically made to asexually reproduce by cuttings
A piece of a plant’s stem is taken from a healthy plant, and placed into soil to grow into a new plant
Male gamete in a plant
Pollen
Female gamete in a plant
Ova
Features of a wind-pollinated plant
- stamen and stigma exposed outside petals
- Feathery petals
- Small, green petals
- No nectaries
Features of a wind pollinated flower
- Stamen exposed outside petals
- Feathery stigma exposed outside petals
- Small, green petals
- No nectaries
Features of an insect pollinated flower
- Stamen enclosed within flower
- Sticky stigma enclosed within flower
- Large and brightly coloured petals
- Nectaries to attract insects
How does a pollen grain casue fertilisation
- Pollen grain lands of stigma
- Enymes secreted that digest tissues of style
- Pollen tube made
- Pollen grain enters ovule through micropyle
- Fuses with ovum
- Divides to form an embryo
How is fruit formed after fertilisation
- Zygote develops into embryonic plant with radicle and plumule
- Ovule becomes cotyledons for food storage
- Ovule wall becomes seed coat - testa
- Ovary wall becomes fruit
Conditions required for germination
- Oxygen for respiration
- Warmth for optimum temperature of enzymes
- Water to activate enzymes
How long do germinating seeds use carbohydrate stores for respiration
Until they can photosynthesise
Secondary sexual characteristics of men
- Voice breaks
- Production of sperm
- Facial, armpit, body and pubic hair growth
- Greater muscle development
- Growth and development of genitalia
- Mood swings
- Acne
