Use LEFT and RIGHT arrow keys to navigate between flashcards;
Use UP and DOWN arrow keys to flip the card;
H to show hint;
A reads text to speech;
27 Cards in this Set
- Front
- Back
|
Receptacle |
4-node stem |
|
|
What does the receptacle support? |
4 whorls of modified leaves |
|
|
What are the 4 whorls of modified leaves supported by the receptacle? |
1. Calyx (sepals) 2. Corolla (petals) 3. Androecium (stamens) 4. Gynoecium (carpels) |
|
|
Microsporangium |
Sporangium in the anther where the male gametophyte is formed |
|
|
Megasporangium |
Sporangium in the ovary where the female gametophyte is formed |
|
|
How do diploid microspore and megaspore mother cells divide? |
Through meiosis |
|
|
What forms as a result of meiosis division of microspore and megaspore mother cells? |
4 haploid spores |
|
|
What initiates gametophyte phase? |
The microspore and megaspore mother cells that are formed through meiosis. |
|
|
After ___ male and ___ female mitotic divisions, micro- and megagametophytes have been formed. |
After 2 male and 3 female mitotic divisions, micro- and megagametophytes have been formed. |
|
|
What 3 things are in the carpel (vertical cross section)? |
1. Ovary 2. Locule (interior chamber) 3. Ovule within locule |
|
|
What 3 chambers are fused into the carpel (horizontal cross section)? |
1. Sepal 2. Petal 3. Anther |
|
|
Microsporgenesis |
Development of male gametophyte with anther |
|
|
6 Steps to Microsporogenesis (2-celled) |
1. Pollen mother cell in anther goes through meiosis 2. Pollen tetrad 3. Microsporocytes fall apart 4. Microsporocytes swell and form wall 5. First pollen division (1 vegetative cell and 1 generative cell in each cytoplasm) - One of cells rounds up and floats in cytoplasm 6. Pollen germinates on stigma |
|
|
8 Steps to Microsporogenesis (3-celled) |
1. Pollen mother cell in anther goes through meiosis 2. Pollen tetrad 3. Microsporocytes fall apart 4. Microsporocytes swell and form wall 5. First pollen division (1 vegetative cell and 1 generative cell in each cytoplasm) - One of cells rounds up and floats in cytoplasm 6. Second division in generative cell (1 vegetative cell and 2 sperm cells) 7. Pollen shed at 3-celled stage 8. Pollen germinates on stigma |
|
|
2 Potential Results of Microsporogenesis |
1. Male gametophyte that is a two-celled pollen grain (vegetative and generative cells) where the generative cell will later undergo another mitotic division to produce 2 sperm cells. 2. Following mitosis of the generative cell and shown to the left of the box, a 3-celled pollen grain with a vegetative (or tube) cell plus two sperm cells. |
|
|
Megasporogenesis |
Development of female gametophyte |
|
|
Steps to Megasporogenesis |
1. Integument tissue from ovule wall forms diploid megaspore mother cells. 2. A megaspore mother cell undergoes meiosis and forms four megaspores. 3. 3/4 spores formed through meiotic division disintegrate (labeled with the X's) 4. The surviving cell undergoes 3 mitotic divisions to form 8 cells within the ovule in an embryo sac, which form the female gametophyte. 5. 6 nuclei are surrounded by their own cell membrane. 2 remaining nuclei are surrounded by one membrane (polar) - contribute to endosperm through combining with other sperm nucleus. |
|
|
Pollen Tube |
Extension of cell membrane and wall of the pollen grain. It is a long skinny cell with 2-3 nuclei (1 vegetative and 1 generative OR 2 sperm depending when mitosis occurs). |
|
|
Where does the pollen tube grow down to? |
The style through intercellular spaces between cells. |
|
|
What type of cell is important for providing nutrients to the pollen tube and providing directional guidance to growth? |
Style Cells
|
|
|
Generative Nucleus |
Undergoes mitosis while in pollen tube to form 2 sperm cells. |
|
|
Steps to Fertilization |
1. Generative nucleus undergoes mitosis to form 2 sperm cells (can happen during development before pollen is shed). 1 vegetative cell is also present (it is black in the diagram) 3. Tube unites with embryo sac. |
|
|
Location of cells in female gametophyte |
TOP: 3 Antipodal cells MID: 2 Polar nuclei BOTTOM: 2 Synergid cells |
|
|
Double Fertilization |
One sperm nucleus fuses with egg nucleus to form 2n zygote. The other sperm nucleus fuses with 2 polar nuclei to form 3n endosperm. |
|
|
In double fertilization, what becomes endosperm? |
Polar nuclei |
|
|
When is embryo development initiated? |
When the zygote divides once mitotically to form an apical and basal cell. |
|
|
4 Steps to Embryo Development |
1. Basal cell undergoes mitotic divisions to form suspensor anchoring apical cell to nucleus to seed coat. 2. Apical cell divides mitotically to form embryo. 3. Embryo goes through phases (definitive shapes). 4. Lobes in embryo become cotyledons. Between lobes is stem or shoot apical meristem. At the base is the root apical meristem. |
