Labs will be: Tues 58, Wed 36, Thurs 14.
March 78: Harvard Forest (REQUIRED)
April 5 or April 6 : Arnold Arboretum (REQUIRED)
Ponkapoag Bog: April 26 (optional)
Garden in the Woods: May 6 (optional)
Biology of Plants, Evert and Eichhorn (seventh, sixth, or eighth)
Botany of Desire: A Plant’s Eye View of the World. Michael Pollan
Differences between plants and animals
Composed of many types of macromolecules, primarily cellulose (polymer of glucose)
Rosettes (enzymatic complexes), cellulose fibrils. As cell grows, lays down new cell walls on the
inside, cells united by middle lamella.
Can be flexible in some spots and rigid in others to produce complex structures.
Endosymbiotic event – both plants and animals took in the prokaryote mitochondria, but only plants
took in the plastids.
The last common ancestor of plants and animals was unicellular, and multicellularity evolved
independently in each
(All of these are interrelated)
Vacuoles (membrane bound organelle)
Important for plant growth – involved in storage. Different solutes can be pumped into vacuole –
creates an osmotic gradient. Higher concentratin of molecules inside vacuole, so water enters
vacuole and causes it to swell. Vacuole blows up like balloon, pushes against cell wall, creates
turgor pressure, creates rigidity that helps plant stand up and not wilt.
Plasmodesmata Highly regulated tubes connecting one cell to another, so proteins, nucleic acids, etc can move cell
to cell – not just open, it’s regulated. Symplast – entire cytoplasmic space of a plant. Highly
connected. The entire space of cell wall is called apoplast.
Cytokinesis with phragmoplast
Can’t just pinch off cells to build new cells – need to build new cell wall. Phragmoplast is a complex
cytoskeletal structure that builds new cell between nuclei that have mitosed. Once you’ve created a
cell wall, very difficult to get rid of it. So, make very conscious decisions on where