Fertilization Flashcards
1
Q
Mechanisms to promote cross-fertilization
A
- Asynchronous dev. of antheridia & archegonia - egg & sperm mature @ different times
- Development of unisexual gametophytes
2
Q
Triggers
A
- H2O
2. Chemical Gradient
3
Q
H2O Roles
A
a. Causes cap cell to pop off the mature antheridium - sperm are released
b. Activates the sperm
c. Medium for sperm to swim
d. H2O causes canal cells to degenerate
4
Q
Chemical Gradient roles
A
a. Release of viscous goo
b. Malic acid in goo attracts sperm
c. Chemotaxis lead sperm to egg
d. Goo traps sperm in area of archegonium
5
Q
Process
A
- Sperm travels up canal
- Tiny hole on egg cell wall only allows 1 sperm through (block to polyspermy)
- Egg cytoplasm & P.M. rise to meet sperm, actin polymerizes = MFs to help engulf sperm
- Egg secretes ECM to block hole
- Egg & Sperm nuclei fuse –> Zygote (2N)
6
Q
4 Cell division
A
1st division - vertical
2nd division - horizontal
7
Q
Foot
A
Top right cell: found in embryonic sporophyte, anchors sporophyte into the gametophyte & absorbs nutrients from gametophyte
8
Q
RAM
A
Bottom right cell: root apical meristem
9
Q
SAM
A
Top left cell: shot apical meristem
10
Q
1st Leaf of Sporophyte
A
Bottom left cell in 4-cell stage
