Catégories : Tous - spores - camp

par Jenny Doriot Il y a 16 années

384

Slime Molds

Slime molds exhibit fascinating life cycles with distinct behaviors and structural transformations. Plasmoidal slime molds consist of a mass of protoplasm containing many nuclei, moving as a single giant amoeba to consume debris and bacteria.

Slime Molds

Slime Molds

Plasmoidal Slime Molds

10. develop into multinucleated plasmodium
9. fuse to form diploid cells
8. spores germinate when conditions right
7. spores released
6. nuclei undergo meiosis and form uninucleate haploid cells
5. spores develop
4. each group forms a stalked sporangium
3. when food in short supply, plasmodium separates into many groups of protoplasm
2. cytoplasmic streaming: protoplasm moves w/in and changes both direction and speed so the oxygen and nutrients are distributed evenly
1. entire plasmodium moves as giant amoeba eating debris and bacteria
mass of protoplasm with many nuclei

Cellular Slime Molds

Life Cycle
9. germinate to form single amoebas
8. spores are released
7. most form into spores
6. some form stalk, some form spore cap
5. a few hours later, slug stops and forms different structures
4. structure is enclosed in slimy sheath = slug. Slug migrates toward light
3. aggregation occurs b/c some amoebas produce cAMP which attracts other amoeba
2. large #s of these cells aggregate to form one single structure
1. amoebid cells ingest fungi by phagocytosis
eukaryotic cells that resemble amoebas