Angiosperm Review Sheet

What is an angiosperm?

•A plant that has flowers and produces seeds enclosed within a carpel

Structure and Function

Sepal: Protects flower bud before it opens

Petal: Usually the most colourful parts of the flower, it attracts pollinators

Stamen: Male reproductive parts of a flower

Carpel: Female reproductive parts of a flower

Anther: Made up of lobes containing pollen that attach to the filament

Filament: Stalk that holds the anther

Ovary: Protects ovule after fertilization and becomes the fruit

Ovule (inside the ovary): Structure developing in the ovary and contains the gamete which develops into the seed.

Receptacle: Thickened part of the stem where the flower organs are attached

Vascular tissue

-xylem: transports water and nutrients from the roots to the leaves

- phloem: transports sugars everywhere throughout the plant

Cuticle:Waxy layer on top of the leaves that helps leaves to retain water

Roots:Absorb water and nutrients

Leaves: Convert the sun’s energy into food for the plant

Stem: Supports the leaves, flowers, and fruits by connecting them to the root and conducts water, nutrients, and products of photosynthesis to and from roots and leaves

Reproduction Cycle

Pollen development

  1. In the anther there is a microspore mother cell
  2. The microspore mother cell goes through meiosis producing microspores which are haploid
  3. The microspores go through mitosis producing pollen grains (male gametophytes)

Inside the male gametophyte there are two distinct cells

- generative cell- generates sperm cells

- tube cell- makes a tube to the style to the ovary

Egg development

  1. In the ovary, in every ovule there is a megaspore mother cell.
  1. It goes though meiosis creating 4 haploid megaspores.
  2. Usually, three of the megaspores die off so there is one left.
  3. This megaspore goes through mitosis 3 times producing 8 nuclei.
  4. With the 8 nuclei, we end up with 5 synergids (each n), one egg cell (n), and polar nuclei(n+n).

Fertilization

  1. The tube cell creates a tube to go through the style and into the ovary. The generative cell creates two sperm cells that travel down the tube.
  2. One of the sperm cells combine with the endosperm mother cell which makes it triploid and the other cell combines with the egg to make a zygote (2n). This is called double fertilization. At this point the synergidsaren’t there anymore.
  3. The zygote divides by mitosis and turns into the embryo as the endosperm surrounds and provides food for the embryo.
  4. The embryo matures the ovule and ovule separates from the wall of the ovary.
  5. The outer covering thickens and hardens into a seed coat, forming a seed.
  6. With the seed inside the ovary, the ovary swells and the flower parts fall off producing the fruit.

Examples

Lilies, magnolias, tomato plants, etc

Test Questions

What makes angiosperms different from gymnosperms?

After the megaspore goes through mitosis 3 times, what happens to the 8 nuclei?

Why are fruits so important to plants?