Fertilization

Question 1

Mechanisms to promote cross-fertilization

Answer 1

1. Asynchronous dev. of antheridia & archegonia - egg & sperm mature @ different times
2. Development of unisexual gametophytes

Question 2

Triggers

Answer 2

1. H2O

2. Chemical Gradient

Question 3

H2O Roles

Answer 3

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

Question 4

Chemical Gradient roles

Answer 4

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

Question 5

Process

Answer 5

1. Sperm travels up canal
2. Tiny hole on egg cell wall only allows 1 sperm through (block to polyspermy)
3. Egg cytoplasm & P.M. rise to meet sperm, actin polymerizes = MFs to help engulf sperm
4. Egg secretes ECM to block hole
5. Egg & Sperm nuclei fuse –> Zygote (2N)

Question 6

4 Cell division

Answer 6

1st division - vertical

2nd division - horizontal

Question 7

Foot

Answer 7

Top right cell: found in embryonic sporophyte, anchors sporophyte into the gametophyte & absorbs nutrients from gametophyte

Question 8

RAM

Answer 8

Bottom right cell: root apical meristem

Question 9

SAM

Answer 9

Top left cell: shot apical meristem

Question 10

1st Leaf of Sporophyte

Answer 10

Bottom left cell in 4-cell stage