Life cycle of a flower plant

Question 1

In the Ovary…

Answer 1

• An ovule is formed
• In the ovule is a diploid megaspore mother cell that undergoes meiosis to produce 4 haploid megaspore cells
• Only one of the 4 cells survives and undergoes 3 mitotic divisions to produce 8 haploid nuclei
  –> Multi-nucleated cell is called the embryonic sac
  –> cell walls begin to form around the nuclies
• 3 cells form near the micropyle opening of ovule
  –> 2 of those cells are synergids that help to direct pollen to the egg cell, and the other cell is the egg cell
  –> 3 cells form across micrpoyle opening of ovule called the anitpodal cells that provide nutrients to devolping embryo
• One cell has 2 nuclie called the polar nuclie that fuses with the sperm to create a 3n cell that will divide to form the endosperm
  –> endosperm provides essential nutreints for the devolping embryo

Question 2

In the anther

Answer 2

• A microspore mother cell divides to form 4 haploid microspore cells
• Microspore cell develops into a pollen grain
  A pollen grain consists of
• Tube cell
• Generative cell
• Thick protective cell wall

Question 3

Double fertilization

Answer 3

• Pollen lands on the stigma
• Tube cell in pollen grain begins to elongate to direct the pollen from the stigma to the ovule (where the egg cell is)
• As this is happening, the generative cell undergoes mitsosis to produce 2 sperm cells
• One sperm cell will fertizlie the egg cell to form the zygote
• other sperm cell with fuse with the polar nuclie to form a 3n cell that will divide to form the endosperm
  –> endosperm will provide essential nutreints for devolping embryo

Question 4

seed devolpment

Answer 4

zygote will divide to form the embryo with one or two cotyledons (depending if monocot or dicot)
–> Cotyledon is an embryonic leaf, part of the embryo within the seed of the plant
- Embryonic stem is the hypocotyl. First part to emerge from the soil up to over overground and will later become the lower part of stem
–> in monocots stays in the ground
- Embryonic root is the radicle
–> first part of the seed that emerges and grows down in the soil and later develops into roots
- As the endosperm matures, the ovule walls become harder, forming the seed coat, which protects the seed and ensures safe dispersal
- In monocots, the nutrients is stored in endosperm, in dicots stored in cotyledon

Question 5

Fruit devolpemnt

Answer 5

• fruit devolps when walls of ovary become hard
• Protect and disperses dormant seeds

Question 6

simple fruits

Answer 6

form from single ovary

Question 7

aggertae fruits

Answer 7

form from single flower with many ovaries

Question 8

Multiple fruits

Answer 8

form many flowers

Question 9

seed germination

Answer 9

seeds can grow if planted in soil with sufficient soil, oxygen and warmth levels; otherwise, they go to dormancy
- dormancy stops when gibberellin (hormone) is released into the seed and initiates germination
- Different seeds have different requirements to be woken up from dormancy
- Germination: when a seed grows into a seedling
- Nutrients in the endosperm or cotyledon break down
- The seed absorbs water, swells, and breaks open the seed coat
- oxygen diffuses in and cellular respiration occurs to provide energy for the embryo’s growth

Question 10

seed dispered

Answer 10

• animal eats fruit and disperses seed through waiste
• attaches to animals fur
• water or wind
• buried in the soil