Sexual Reproduction in Plants - finished Flashcards
What is the function of a petal in an insect pollinated flower?
Bright and Colourful to attract insects
Landing pads
What is the function of the stigma?
Sticky - Where pollen lands
What is the function of the anther?
Produce pollen
What is the function of the filament?
To hold the anther in place
What is the collective term for the filament and the anther?
Stamen
What is the function of the ovary?
Site of ovule formation
What is the receptacle
Swollen stem to support the flower
What is the function of the sepal?
Protects the flower in bud
What are the differences in a wind pollinated plant?
Large Surface Area of stigma - To catch pollen
Anther and Stigma outside the body of the flower - to allow pollen to catch the breeze/ catch pollen in the wind
NO petals/Nectary - No attraction of insects
What is a nectary?
Buds of nectar used to attract insects/birds
Where is pollen made?
in the anther
Cells of the tapetum divide meiotically to produce the pollen. When the anther matures the pollen sacs burst open and the anther turns itself inside out.
how does pollen prevent dehydration?
It has 2 walls
What adaptations does wind pollen have?
Large S.A./Wings
Small/Smooth
What adaptations does insect pollen have?
Hooks to attach itself to the insect/
Which type of pollen is produced in larger quantities?
Wind pollen
What is the definition of pollination?
Transferal of pollen from the anther to the stigma
What is cross pollination?
Pollen from the anther of a different flower lands on the stigma
What is self pollination?
Pollen from the anther lands on the stigma of the same flower.
What is the best type of pollination?
Cross Pollination
Give an advantage and Disadvantage of Self pollination?
Advantage - Short distance for pollen to travel
Disadvantage - limited variability
Give an advantage and disadvantage of cross pollination?
Advantage - Better Genetic variability
Disadvantage - Less chance of pollination if isolated
How do you ensure cross pollination/ prevent self pollination?
- Relative positions of anther and stigma inside the flower (short stigma/high anthers)(high stigma/low anthers)
- Prevent pollen grains germinating/growing if self pollination occurs
- Have male/female structures maturing at different times
- single sex flowers
What happens during pollenation?
The pollen grain contains two nuclei . one of which is the gamete, the other secretes enzymes which digest cells to create a path through the carpel to the micropyle. The micropyle degenerates and the female and male gamete fuse.
What happens to the ovule after fetilization?
it becomes a seed.
Integuments become testa (seed coat) - to protect the seed in the ground
The zygote becomes an embryonic plant which splits into the Plumule (shoot) and the Radicle (root)
What is a cotyledon?
A food store inside a seed.
Give an example of a dicotyledon seed (a seed with with 2 cotyledon) and a single cotyledon seed
Dicotyledon seed - Broad bean
one cotyledon seed - Maize.
What is an endosperm?
A secondary food supply in a seed.
What do seeds need before germination can happen?
Water
Oxygen
Suitable temperate for enzymes to work
What happens if a seed if dry?
it is dormant
What happens during germination?
Water enters the micropyle, the seed swells up and the testa splits.
hydrolysis of stored foos.
Starch is broken down by amylase into maltose which is transported to the embryo and then broken down by maltase into alpha glucose.
The alpha glucose can be used to make lipids and proteins that make enzymes, it can be used in respiration and can also be converted to beta glucose and used to produce cellulose
