Sexual Reproduction In Plants Flashcards
(32 cards)
Petals
Wind -… & … or none at all. Flowers are … the leaves & produce in early … to give max advantage from wind … without interference from …
Insect - … & brightly …, often with guidelines to the … to attract insect …
Small & green
Above
Spring
Currents
Leaves
Large & coloured
Nectaries
Pollinators
Stigma
Wind - l… & f… and hang … the flower to catch airborne … in wind currents
Insect - … to trap … grains and is … the flower, where insects … against it causing pollen deposit
Large
Feathery
Outside
Pollen
Sticky
Pollen
Inside
Rub
Anthers
Wind - … & suspended … the flower to release .. grains into wind …
Insect - on rigid …, … the flower where insects must rub against - increase chance of pollen deposit on insect …
Large
Outside
Pollen
Currents
Filaments
Inside
Body
Pollen
Wind - vast amount of …, …, …-walled pollen grains that are easily … by wind
Insects - … with … walls to … to insect bodies
Small, light, smooth
Carried
Large
Spiky
Stick
Stomium (point of dehiscence)
When pollen grains are mature, outer layers of the anther … out;
… in the l… g… causes dehiscence - … of the anther pull apart releasing pollen …
Dry
Tension
Lateral groove
Walls
Grains
Development of an Ovule
- Ovule contains the … surrounding by 2 protective …, the ovule is carried on a short stalk called the …, one cell within the nucellus develops into the m… m… cells (2n)
- … of the mother cells produces 4 … mega spores (n)
- 3 of the haploid mega spores … & 1 develops into the e… s…
- 3 … divisions occur forming … haploid nuclei (n)
- 2 nuclei move to centre forming … nuclei (n), remaining nuclei develop … around the, & separate by cell …
- 3 … cells opposite the … play no further role, cell nearest micropyle develops … gametes - 2 other form … that … after …
- Nucellus, integuments, funicle, megastore mother
- Meiosis, haploid,
- Degenerate, embryo sac
- Mitotic, 8
- Polar, cytoplasm, walls
- Antipodal, micropyle, female, synergids, degenerate, fertilisation
Self-pollination
Transfer of … from the … to the … of genetically … flowers on the same … (i…)
… genetic variation
Greater chance of 2 potentially harmful … alleles combining
Successful … are preserved - advantage in … environment but a disadvantage if environment … suddenly
Pollen
Anther
Stigma
Identical
Plant
Inbreeding
Less
Recessive
Genomes
Stable
Changes
Cross-pollination
Transfer of … from the … of one plant to the … of a … on a … plant of the … species (o…)
… genetic variation
… chance of producing harmful … of …
Advantageous (in terms of evolution) bcuz if environment changes suddenly it is more likely that there are individuals within populations with … of … that will allow species to …
Pollen
Anther
Stigma
Flower
Different
Same
Outbreeding
More
Less
Suddenly
Combination of alleles
Survive
Adaptions of flowers to promote cross-pollination
- chemical … - … from ame parent plant are unable to … to from a … (if zygote forms, it fails to develop)
- d… - anthers & stigmas mature at … times
- … flower … - e.g. primrose
Self-incompatibility
Gametes
Fuse
Zygote
Dichogamy
Different
Irregular
Structure
Fertilisation process
- Pollen grain lands on …, if compatible, pollen tube g…
- Pollen … grows down th … due to … enzymatic digestion (under control of pollen tube …) which provides a …
- The … nucleus (n) divides by … to form 2 … nuclei (g…)
- Growth of pollen tube towards … secreted by e… s… (chemo trophic response)
- Pollen tubes grows through the … and passes into e… s… which disintegrate the pollen tube …
- Double fertilisation: - one male gamete fuses with the female gamete to form a d… z… (2n), - other male gamete fuses with 2 haploid … nuclei to form a t… e… (3n)
- After fertilisation, a… cells & the s… play no further role
Stigma
Germinates
Tube
Style
Hydrlase
Nucleus
Pathway
Generative
Mitosis
Male (gametes)
Chemicals
Embryo sac
Micropyle
Embryo sac
Nucleus
Diploid zygote
Polar
Triploid endosperm
Antipodal
Synergids
Formation of Seeds
Following fertilisation:
1. D… z… divides by … to form d… e… which differentiates into a young shoot (p…), young root (r…) & one/two seed leaves (…)
2. T… e… divides by … to form e… t… which acts as a …source/store for the developing …
diploid zygote
Mitosis
Diploid embryo
plumule
Radicle
Cotyledons
Tripled endosperm
Mitosis
Endosperm tissue
Food
Embryo
Endosperm
Acts as a … source/store for the growing …
Food
Embryo
Development of fruit
Before vs After fertilisation
Ovule - s…
Integuments - t… (seed coat)
Micropyle- p…
Ovary wall - p… (fruit wall)
Content of ovary - f…
Attachment point of funicle to ovary - h…
Seed
Testa
Pore
Pericarp
Fruit
Hilum
Germination
= … onset of … activity & g… of a seedling until the plant can … and become independent of the food … contained in the e…
Rapid
Biochemical
Growth
Photosynthesise
Stores
Endosperm
Seed germination requirements
… content of seeds is low - prevents germination & keeps seeds …
3 requirements for seed to germinate:
- w… - activates hydrolytic …
- … - … respiration
- suitable … - … enzyme activity
Water
Dormant
Water
Enzymes
Oxygen
Aerobic
Temp
Optimum
Mobilisation of food reserves during germination
- … of starch to sugar in the …
- Dry mass of endosperm … - CO2 is lost when sugar used in …, sugars are sent to …
- Mass of embryo … after receiving sugars from …
- Total mass: decreases at first as … is lost in … respiration, then increases as … produced (p…) begin …
Hydrolysis
Endosperm
Decreases
Respiration
Embryo
Increases
Endosperm
CO2
Aerobic
Leaves
Plumule
Photosynthesising
Germination of Non-endospermic seeds (e.g. Broad Bean)
- … is imbibed through the …
- The … swell and the … splits allowing entry of more w… & o… for … respiration
- S… & p… reserves in the c… are h…
- Products of hydrolysis used as: source of … for r…, g… of the p… & r…
Water
Micropyle
Cotyledons
Testa
Water
Oxygen
Aerobic
Starch & protein
Cotyledons
Hydrolysed
Energy
Respiration
Growth
Plumule
Radicle
Germination of Endospermic seeds (e.g. maize)
- Water is imbibed, … acid is released by …
- Gibberellin … to the a… layer (outer layer of endosperm) which contains …
3.Gibberellin induces production of … enzymes (e.g. amylase) - The hydrolytic enzymes diffuse into the … layer of endosperm & catalyse the break down of … nutrients
- Products (e.g. glucose) diffuse into the … - used for … respiration & g…
Gibberellin
Embryo
Diffuses
Aleurone
Protein
Hydrolytic
Inner
Stored
Embryo
Aerobic
Growth
What is produces at the receptacle?
…
Nectar
Function of nectar
… insects
Attracts
Pollination by insects
Pollen deposited on … (from mature …);
Pollen transferred to …
Insect
Anthers
Stigma
How are self-pollinated flowers adapted to ensure effective pollen transferred between 2 flowers of the same species?
… & … touch same part of bee
Anthers & stigma
How is self-pollination avoided?
Anthers & stigma … at … times
Mature
Different
