3a Flashcards
Sexual reproduction
- The fusion of a male and female gamete to produce a zygote that undergoes cell division and develops into an embryo.
- Genetic variation.
Asexual reproduction
- Reproduction with 1 parent.
- No genetic variation.
Insect pollinated flower
- Colourful petals
- Sticky pollen
- Large petals
- Nectaries
- Anther inside
- Stigma enclosed
- Scent
Wind pollinated flower
- Dull petals
- Small, light-grain pollen
- Small petals
- Anthers outside
- Feathery stigma
- No scent/nectary
Zygote
Fertilised egg cell
Gamete
Sex cell
Mitosis
- Regular cell division (growth & repair) & asexual reproduction
- Diploid nucleus => Same nº chromosomes
- No variation
- 2 cells
Clone
Genetically identical
Meiosis
- Cell division to form gametes
- Haploid nucleus
- Has variation
- 4 cells
Seed/Fruit formation
- Anther held on filament has pollen
- Pollen lands on stigma
- Pollen tube is formed
- Pollen runs down the tube fertilises ovule in ovary
- Ovary forms fruit
- Ovule forms seed
Plants asexual reproduction
Natural:
- Runners
Artificial:
- Cuttings
Role of oestrogen in menstrual cycle
- Repairing uterus lining
- Controls female secondary sexual characteristics
Role of progestrogen in menstural cycle
Completes the thickening of the uterus lining and stops other hormones from causing ovulation.
Role of amniotic fluid
Amniotic fluid surrounds embryo to protect it from sudden movements and bumps
Sperm adaptations
- Sac of enzymes to penetrate membrane around egg
- Flagellum for propulsion
- Mitochondria to release energy for movement
Placenta
- Allows the embryo to obtain materials such as oxygen and nutrients from the mother’s blood.
- Allows the embryo to get rid of waste products such as urea and carbon dioxide
Puberty in boys
Due to testosterone:
- Sperm production starts
- Sexual organs grow and develop
- Growth of hair
- Increase in body mass
- Voice breaks
Puberty in girls
Due to oestrogen:
- Menstrual cycle begins
- Female sexual organs grow and develop
- Growth of hair
- Body mass increases
- Voice deepens
FSH
- Follicle Stimulating Hormone
- Stimulates follicle to start the growth of the egg
- Triggers oestrogen production
LH
- Luteinizing Hormone
- Causes ovulation (females) / Testosterone production (males)
Female reproductive system adaptations and functions
- Egg cell is released into an oviduct (Fallopian tube) from one of the ovaries, ovulation.
- Uterus, where the fertilised egg cell attaches to start developing
- Vagina, where sexual intercourse takes place
Where fertilisation usually take place
Fallopian tube / oviduct
How germinating seeds utilise food reserves
- The absorption of water triggers the synthesis of Amylase
- Amylase breaks starch reserves into glucose
- Glucose can be used as a source of energy via aerobic respiration
