Section 7- Reproduction and Inheritance Flashcards
male reproductive part in flower
Stamen consisting of:
- anther (contains pollen grains that produce male gametes - sperm)
- filament (stalk that supports anther)
female reproductive part of flower
Carpel consists of:
- stigma (end bit that pollen grains are attached to)
- style (rod-like section that supports stigma)
- ovary ( contains female gametes - eggs - inside ovules)
pollination
the transfer of pollen from an anther to a stigma so that the male gametes can fertilise the female gametes in sexual reproduction
cross-pollination
type of sexual reproduction where pollen is transfered from the anther of one plant to stigma of other
plants that cross pollinate rely on things like insects or wind to help thema
adaptations for insect pollination
1) brightly coloured petals to attrct insects
2) scented flowers and nectaries to attract insects
3) they make big, sticky pollen grains that stick to insects from plant to plant
4) stigma is also sticky so pollen picked by insects on other plants will stick to stigma
adaptations for wind pollunation
1) small dull petals on flower and no nectaries with strong scents
3) A LOT of pollen grains - small and light so they can be carried by wind
4) long filaments to hang anthers outside flower so that a lot of pollen gets blown away by wind
5) large feathery stigma to catch polllen and its carried past by the wind. stigma hangs outside flower too
fertailsation in plants
1)pollen grain lands on stigma of flower, usually with help from insects or the wind
2)pollen tube grows out of pollen grain and down through style to ovary and into ovule
3) nucleus from male gamete moves down the tube to meet a female gamete in the ovule. Feltilisation is when these two nuclei fuse together to make a zygote that divides by mitosis to form an embryo
4) each fertilised femae gamete forms a seed, ovary develops fruit around seed
Germination in plants
its when seeds start to grow
seeds will lie dormant until condutions around it are right for germination
1) water - will activate enzymes that break down food reserves
2) oxygen - for respiration which transfers energy from food for growth
3) suitable temperature - for enzymes in seed to work, this depends on type if seed
food stores in plants
1) a developed seed contains an embryo and a store of food reserves wrapped in a hard seed coat
2) when seed starts to germinate it gets glucose for respiration from its own food store, this transfers the energy it needs to grow
3) once plant has grown enough to produce green leaves it can get its own food for energy from photosynthesis
cloning plants: reproducing asexually
1) gardenders take cutting from parent plants and plant them to produce genetically identical copies of parent plant
2)this is quick and cheap
natural methods for asexual reproduction
plants can grow new plants from stems: example;
strawberry plant
1) parent strawberry plant sends out runners (fast growing stems that grow out sideways just above ground)
2) runners take root at various points and new plants start to grow
3) these new plants are clones of parent strawberry plant so there is no genetic variation
male reproductive system
- sperm - male gamete, made in testes
- semen - sperm mixes with a liquid to make semen which is ejaculated from penis into vagina druing sexual intercourse
- urthea - tube which carries sperm through the penis during ejaculatiion. urea also pases through urthea to exit body
- erectile tissue - swells when filled with blood to make penis erect
- testis - where sperm is made
- glands - produce liquid thats added to sperm to make semen
- vas deferens (sperm duct) - muscular tube that carries sperm from testis towards the urthea
- foreskin
- head of penis
- scrotal sac (scrotal sac) - hangs behind penis and contains testes
female reproductive system parts
- fallopian tube (oviduct) - muscular tube that carries ovum from ovary to uterus
- uterus wall - muscular
- ovary - the organ that produces ova and sex hormones
- uterus ( womb) - organ where embryo grows
- vulva
- vagina - where sperm is deposited
- cervix - the neck of uterus
- endometrium (lining of uterus) - good blood supply for implantation of uterus
female sex hormones
ostrogen trigggers secondary sexual charateristics:
- extra hair on underarms and pubic area
- hips widen
- development of breasts
- ovum release and start periods
male sex hormones
testosterone trigggers secondary sexual charateristics
- extra hair on face and body
- muscles develop
- penis and testicles enlarge
- sperm production
- deepening of voice
