4.1 Sexual Reproduction In Plants Flashcards
Name 8 structures of a flower
- Sepal
- Receptacle
- Petal
- Anther
- Filament
- Stigma
- Style
- Ovary
Name the parts of the flower thats in the Stamen
Fillament and anther
Male part
Name the parts of the flower thats in the Carpel
Stigma
Style
Ovary
Female part
Name the 4 modified set of leaves within a flower
Calyx
Corolla
Stamens
Carpel
Function of:
Petals
Colourfull to attract insects
Function of:
Stamen
The male part of the flower -made of the filament and anther
Function of:
Filament
Supports the anther
Function of:
Anther
Produces pollen grains
Function of:
Carpel
Female part of the flower - stigma, style and ovary
Function of:
Stigma
Collects pollen
Sticky
Function of:
Style
Connects stigma to ovary
Function of:
Ovule
The egg cell
Function of:
Sepals
Protect flower in bud
Function of:
Ovary
Produces egg
Function of:
Pollen grain
Contains the male reproductive gammete
What’s pollination?
the transfer of pollen from the anther of one flower to the mature stigma of another flower of the same species
Explain the development of the male gammete
- A diploid mother cell undergoes MEISOIS
- To form a tetrad of four haploid pollen cells
- Then cells seporate to produce 4 imature pollen grains
- Young pollen grain undergoes MITOSIS to form a Generative neucleus and a Pollen tube nucleus
- Generative nucleus undergoes MEISOIS to form 2 male nuclei
What’s dehiscence?
the opening of the anther, releasing pollen grains
Explain the development of the female gamete
- Diploid megaspore mother cell undergoes MEIOSIS to produce 4 haploid megaspores
- 3 disintigrates
- Other undergoes 3 rounds of MITOSIS to form 8 haploid nuclei
- 2 polar nuclei fuse to from a diploid polar nucleus
What’s the female gamet called?
oosphere
Whats self polination?
Occurs when pollen falls from the anther onto the stigma of the same flower on the same plant
How do flowers provent pollination?
- have stigmas above stamen
OR - Dichogamy: Stamen and stigma mature at different times
Protandry = stigma ripens first
Protogyny = stigma ripens first
Explain double fertilisation
- When a compatible pollen grain lands on the stigma it germinates in the sucrose solution secreted by the stigma and produce a pollen tube
- Pollen tuble grows out of gap in cell wall of pollen grain
- PG travells down the style up a concentration gradient of chemattractants from ovule (digesting its way down style)
- Pollen tube nucleus is at tip of the with the 2 male nuclei behind
- Pollen tube grows through gap in interguments into embryo sac
- PTN disintigrates after completing it’s function - the growth of PT
- Tip of PT opens 2 male gametes released into embryo sac
- M + F gametes fuse to form a diploid zygote
- Other male gamete fuses with the diploid polar nucleus to form triploid nucleus
Definition of fruit
Develops from the fertilised ovary
-Contains one or more seeds
Definition of seed
Develops from the fertilised ovule
-contains embryonic plant and a food store
Explain what’s a broad bean
- Dicotyledon (2 leaves)
- Non-endospermic seed - endosperm is absorbed into the cotyledons
Explain whats maize
- Monocotyledon
- Endospermic seed - endosperm remains as the food store
What’s a radicle?
Developing root
What’s the plumule
Developing shoot
What’s a testa
Out side coat of seed
Germination defination
the biochemical and physiological processes through which a seed becomes a photosynthesising plant
What are the 3 main requirements for germination?
- Temperature
- Water
- Oxygen
When do seeds germinate?
When conditions are optimum - they remain dormant (inactive) till this
What does water do during germination?
- Seed absorbs water through micropyle
- This mobilises enzymes
- Increases cell size through formation of vaculoes causing testa to split
- Transports materials into seed
What does temperature do during germination?
Optimum temp for enzyme activity
What does oxygen do during germination?
for aerobic respiration - releases energy, fueling metabolism and growth
Name a group of plant hormones responsible for growth and development
Gibberellin
Explain the steps of germination of endospermic seeds
- Water is absorbed through the micropyle
- Gibberellins in the cotyledons are mobilised and carried into the outer layer of endosperm (aleurone)
- This causes DNA to be transcripted into mRNA which is then translated into hydrolytic enzymes (e.g protease and amylase)
- Protease hydrolyse protein in the aleurone layer to amino acids to make amylase and maltase
- Amylase diffuses out of a;eurone layer and hydrolyses the starch stroed in the endosperm to maltoes and then gluscose
- Glucose diffuses to embryo where radicle and plumule use it for respiration + growth
