1. Chapter 38: Angiosperm Reproduction and Biotechnology
38.1
Admit Slip
3. List 3 words you think of when you look at the picture/diagram
2. Write 2 ideas you have based on the picture and your words. If possible, use your words as you write your ideas.
1. Write 1 question you have.

2. Angiosperm Life Cycle Remember the 3 F’s Flowers Fruits
And double Fertilization

3. Pollen
In the microsporangia (pollen sacs) of an anther, diploid cells undergo meiosis
Produces haploid microspores
Each microspore develops into male gametophyte (pollen grain)

4. Pollen Pollen grains have 2 haploid nuclei:
Tube nucleus: produces the pollen tube, long cellular extension that delivers sperm to the female gametophyte, and eventually to the egg
Generative nucleus- divides to yield 2 sperm cells which remain inside the pollen tube

5. In the Ovary
Ovules form with a diploid cell that undergoes meiosis to produce 4 haploid megaspores.
Only 1 survives and divides by mitosis 3 times to form 8 haploid nuclei
3 of these are important
1 haploid nucleus is the egg
2 haploid nuclei are the polar nuclei and fuse with a sperm to make a 3n endosperm

6. Female gametophyte (embryo sac)
Development of a male
gametophyte (in pollen grain)
(b)
Development of a female
gametophyte (embryo sac)
Microsporangium
(pollen sac)
Megasporangium (2n)
Microsporocyte (2n)
Ovule
Megasporocyte (2n)
MEIOSIS
Integuments (2n)
Micropyle
4 microspores (n)
Surviving
megaspore (n)
Each of 4
microspores (n)
MITOSIS
Ovule
Generative cell (n)
Male
gametophyte
3 antipodal cells (n)
Female gametophyte
(embryo sac)
2 polar nuclei (n)
1 egg (n)
Nucleus of
tube cell (n)
Integuments (2n)
2 synergids (n)
20 µm
Ragweed
pollen
grain
Embryo
sac
75 µm
100 µm

7. Pollination The transfer of pollen from an anther to stigma
if successful, a pollen tube forms-grows down into the ovary

8. Pollination
When the pollen tube reaches the ovary, 2 fertilization events (double fertilization) occur;
One sperm fertilizes the egg forming the zygote (develops into the embryo and eventually sporophyte)
One sperm combines with 2 polar nuclei forming a 3n nucleus=endosperm (food-storing tissue in the seed)

9. After Fertilization The ovule develops into a seed
Ovary develops into a fruit
The fruit protects the enclosed seed and aides in dispersal
The endosperm is used to make cotyledons
The seed coat protects the embryo and endosperm

12. Seed Maturation Seed enters dormancy
Low metabolic rate
Growth and development are suspended
The seed will resume growth when there are suitable environmental conditions for germination