The document summarizes the parts of a flower and the process of sexual reproduction in flowering plants. It describes the key parts of a flower including the pistil (female) containing the stigma, style, and ovary, and the stamen (male) containing the filament and anther. It explains that the ovary houses the ovules containing egg cells, and the anther produces pollen. The document also summarizes the processes of megasporogenesis and megagametogenesis that produce the egg in the ovule, and microsporogenesis and microgametogenesis that produce pollen grains in the anther. Fertilization occurs when pollen lands on the stigma and a pollen tube delivers
4. Two Types of Reproduction
Sexual – involves sex cells (egg, sperm)
Asexual – does not involve sex cells
5. Refer to p.125
In asexual
reproduction, the
parent cell is SINGLE
AND DIVIDING.
(ex. amoeba, hydra,
fungi, bacteria, etc.)
6. Refer to p.125
In sexual reproduction,
the offspring are
genetically identical
(exact clones) to their
parents.
(ex. humans,
elephants, dogs, fishes,
plants, etc.)
7.
8. Sexual Reproduction
Involves union of gametes
Gametes = sperm (male) +
egg (female)
Trivia: The egg is the largest
cell in the human body
while the sperm is the
smallest.
9. Sexual Reproduction
Sperm – mobile and small
Egg – immobile and large
During fertilization, they
unite (n + n) to form a
diploid (2n) zygote
(fertilized egg)
11. Flowering Plants
Comprises 90% of plant species
Classified as either:
1. Angiosperms – have seeds enclosed in
ovary
2. Anthophytes – plants that produce flowers.
They have an ovary that’s part of the
flower
24. Pistil or carpel
The female reproductive
organ
Collectively called
gynoecium (collective noun)
Composed of three parts:
1. Stigma
2. Style
3. Ovary
25. Stigma
Swollen tip of the
pistil
Function:
Covered by sticky
substance for
pollen grains to
adhere (stick) to
stigma Pollen grains
(purple dots)
26. Style
Function: Long,
slender tube that
connects the
stigma to the
ovary
Acts as a
conveyor (carrier
from one place to
another) of pollen
grains
style
32. Ovary
Ovary core –
solid structure
at the center
Placenta – the
edge of the
core; nourishes
the egg
core (yellow);
placenta (green)
Visual representation
core
placenta
placenta
core
37. Cross-section of an ovule
The ovule has the following parts:
1. Integument - 2 layer protective coat
2. Nucellus – mass of tissue consisting of
meristematic (dividing) cells
3. Funiculus
4. Embryo sac – contains the egg
39. Development of Gametophytes
(Egg) Two Stages
1. Megasporogenesis (genesis = beginning/creation) –
creation of megaspores
2. Megagametogenesis – creation of the gametes (egg)
40. Development of Gametophytes
(Egg)
1. Megasporogenesis
A. Ovule produces megaspore
mother cell (2n).
B. Megaspore mother cell
(2n) produces 4
megaspores (n) via a two-
time meiosis.
C. 3 megaspores die and only
one is left to continue.
2n
n n
meiosis
n n
meiosis
n n
meiosis
41. Development of Gametophytes
(Egg)
1. Megagametogenesis
A. The surviving
megaspore divides
via mitosis 3 times,
forming 8 haploid
(n) cells)
n megaspore
n n
n n n n
nnnnnnnn
mitosis
mitosis mitosis
mitosismitosismitosismitosis
8 haploid (n) cells
42. Egg Development in Ovule
B. Among the eight cells:
3 cells migrate near the micropyle.
The one at the center becomes the
egg while the other two becomes
the synergid cells.
The other 3 migrate on the opposite
pole and become antipodal cells.
The remaining 2 cells are naked (no
membrane) and remains at the
center to become the polar nuclei.
micropyle
egg
synergidsynergid
antipodal
polar nuclei
43.
44. Egg Development in Ovule
C. These 8 cells form
the inside of the
embryo sac and are
ready to be
fertilized by a
pollen (from the
male).
45.
46. Pollen Development in the
Anther (Male)
Like egg development, pollen
development undergoes meiosis and
mitosis to produce pollen grains.
The product is 2 pollen grains.
1. Microsporogenesis – creation of
microspore
2. Microgametosgenesis – creation
of male gametes (pollen)